Earth Definition and 1000 Threads

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It may not display this or other websites correctly.<br />You should upgrade or use an <a href="https://www.google.com/chrome/" target="_blank" rel="noopener">alternative browser</a>.</div> <div class="p-body-main "> <div class="p-body-contentCol"></div> <div class="p-body-content"> <div class="p-body-pageContent"> <div class="p-breadcrumbs--parent "> <ul class="p-breadcrumbs " itemscope itemtype="https://schema.org/BreadcrumbList"> <li itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem"> <a href="https://www.physicsforums.com/" itemprop="item"> <span itemprop="name">Forums</span> </a> <meta itemprop="position" content="1" /> </li> <li itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem"> <a href="/tags/" itemprop="item"> <span itemprop="name">Tags</span> </a> <meta itemprop="position" content="2" /> </li> </ul> </div> <div class="p-body-header"> <div class="p-title "> <h1 class="p-title-value">Earth Definition and 1000 Threads</h1> </div> </div> <div class="tabs tabs--standalone"> <div class="hScroller" data-xf-init="h-scroller"> <span class="hScroller-scroll"> <a class="tabs-tab is-active" href="/tags/earth/">Recent contents</a> <a class="tabs-tab " href="/tags/earth/wiki">View information</a> <a class="tabs-tab " href="/tags/earth/top-users">Top users</a> </span> </div> </div> <div class="block" data-xf-init="" data-type="" data-href="/inline-mod/"> <div class="block-container"> <ol class="block-body"> <li class="block-row block-row--separated js-inlineModContainer" data-author="synch"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/synch.587434/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="587434" data-xf-init="member-tooltip" style="background-color: #3b2b2b; color: #9d7b7b"> <span class="avatar-u587434-s" role="img" aria-label="synch">S</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/power-from-global-loop-power-cable.1078634/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Power from global loop power cable ?</a> </h3> <div class="contentRow-snippet">Just a thought ... Given that the earths magnetic field has a stream of small changes, would a power transmission line forming a loop around the equator generate useful power ? Not exactly economic of course. Maybe just circumnavigating the arctic circle would be enough ?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/synch.587434/" class="username " dir="auto" data-user-id="587434" data-xf-init="member-tooltip">synch</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2025-02-17T19:53:00-0600" data-time="1739843580" data-date-string="Feb 17, 2025" data-time-string="7:53 PM" title="Feb 17, 2025 at 7:53 PM">Monday, 7:53 PM</time></li> <li> <dl class="tagList tagList--thread-1078634 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/field/" data-xf-init="preview-tooltip" data-preview-url="/tags/field/preview" class="tagItem tagItem--tag_field" dir="auto"> Field </a> <a href="/tags/magnetic/" data-xf-init="preview-tooltip" data-preview-url="/tags/magnetic/preview" class="tagItem tagItem--tag_magnetic" dir="auto"> Magnetic </a> </span> </dd> </dl> </li> <li>Replies: 1</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="zasvitim"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/zasvitim.701623/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="701623" data-xf-init="member-tooltip" style="background-color: #7a5c1f; color: #dbb870"> <span class="avatar-u701623-s" role="img" aria-label="zasvitim">Z</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/can-we-measure-absolute-motion-of-earth-and-sun.1068113/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Can we measure absolute motion of Earth and Sun?</a> </h3> <div class="contentRow-snippet">Slow particles (solar wind) should come from a direction that is different than the direction photons come from: it takes slow particles more time to reach the Earth, therefore slow particles should be emitted earlier. Some calculations: - Sun diameter is about 1400000 km - solar wind speed is...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/zasvitim.701623/" class="username " dir="auto" data-user-id="701623" data-xf-init="member-tooltip">zasvitim</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2025-01-14T04:23:08-0600" data-time="1736850188" data-date-string="Jan 14, 2025" data-time-string="4:23 AM" title="Jan 14, 2025 at 4:23 AM">Jan 14, 2025</time></li> <li> <dl class="tagList tagList--thread-1068113 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/solar-wind/" data-xf-init="preview-tooltip" data-preview-url="/tags/solar-wind/preview" class="tagItem tagItem--tag_solar-wind" dir="auto"> Solar wind </a> </span> </dd> </dl> </li> <li>Replies: 57</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="D H"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/d-h.42688/" class="avatar avatar--s" data-user-id="42688" data-xf-init="member-tooltip"> <img src="/data/avatars/s/42/42688.jpg?1431189024" srcset="/data/avatars/m/42/42688.jpg?1431189024 2x" alt="D H" class="avatar-u42688-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/beyond-the-tidal-bulge.1067812/"><span class="prefix insight" dir="auto">Insights</span><span class="label-append"> </span>Beyond the Tidal Bulge</a> </h3> <div class="contentRow-snippet">[url="https://www.physicsforums.com/insights/there-is-no-tidal-bulge-2/"]Continue reading...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/d-h.42688/" class="username " dir="auto" data-user-id="42688" data-xf-init="member-tooltip">D H</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-12-31T08:23:01-0600" data-time="1735654981" data-date-string="Dec 31, 2024" data-time-string="8:23 AM" title="Dec 31, 2024 at 8:23 AM">Dec 31, 2024</time></li> <li> <dl class="tagList tagList--thread-1067812 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/tidal/" data-xf-init="preview-tooltip" data-preview-url="/tags/tidal/preview" class="tagItem tagItem--tag_tidal" dir="auto"> Tidal </a> </span> </dd> </dl> </li> <li>Replies: 22</li> <li>Forum: <a href="/forums/earth-sciences.84/">Earth Sciences</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="mcastillo356"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/mcastillo356.506793/" class="avatar avatar--s" data-user-id="506793" data-xf-init="member-tooltip"> <img src="/data/avatars/s/506/506793.jpg?1605370403" srcset="/data/avatars/m/506/506793.jpg?1605370403 2x" alt="mcastillo356" class="avatar-u506793-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/wasnt-parker-solar-probe-about-to-resume-communication-with-earth.1067709/"><span class="prefix gray" dir="auto">News</span><span class="label-append"> </span>Wasn't Parker Solar Probe about to resume communication with Earth?</a> </h3> <div class="contentRow-snippet">Hi, Physics Forums https://en.wikipedia.org/wiki/Parker_Solar_Probe I haven't found any clue on Wiki, though this website is updated to two hours ago. I suppose this is not good news. Does anybody know anything? Love and Peace Marcos</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/mcastillo356.506793/" class="username " dir="auto" data-user-id="506793" data-xf-init="member-tooltip">mcastillo356</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-12-26T06:21:45-0600" data-time="1735215705" data-date-string="Dec 26, 2024" data-time-string="6:21 AM" title="Dec 26, 2024 at 6:21 AM">Dec 26, 2024</time></li> <li> <dl class="tagList tagList--thread-1067709 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/communication/" data-xf-init="preview-tooltip" data-preview-url="/tags/communication/preview" class="tagItem tagItem--tag_communication" dir="auto"> Communication </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/probe/" data-xf-init="preview-tooltip" data-preview-url="/tags/probe/preview" class="tagItem tagItem--tag_probe" dir="auto"> Probe </a> </span> </dd> </dl> </li> <li>Replies: 5</li> <li>Forum: <a href="/forums/general-discussion.14/">General Discussion</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="achap01"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/achap01.754576/" class="avatar avatar--s" data-user-id="754576" data-xf-init="member-tooltip"> <img src="/data/avatars/s/754/754576.jpg?1730951106" srcset="/data/avatars/m/754/754576.jpg?1730951106 2x" alt="achap01" class="avatar-u754576-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/freefall-chord-through-the-earth-calculus-proof.1066771/">Freefall chord through the Earth -- calculus proof</a> </h3> <div class="contentRow-snippet">I haven't really attempted anything worth showing on the calculus side</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/achap01.754576/" class="username " dir="auto" data-user-id="754576" data-xf-init="member-tooltip">achap01</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-11-06T22:00:51-0600" data-time="1730952051" data-date-string="Nov 6, 2024" data-time-string="10:00 PM" title="Nov 6, 2024 at 10:00 PM">Nov 6, 2024</time></li> <li> <dl class="tagList tagList--thread-1066771 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/chord/" data-xf-init="preview-tooltip" data-preview-url="/tags/chord/preview" class="tagItem tagItem--tag_chord" dir="auto"> Chord </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/freefall/" data-xf-init="preview-tooltip" data-preview-url="/tags/freefall/preview" class="tagItem tagItem--tag_freefall" dir="auto"> Freefall </a> </span> </dd> </dl> </li> <li>Replies: 41</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="johnbbahm"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/johnbbahm.335656/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="335656" data-xf-init="member-tooltip" style="background-color: #adebcc; color: #2eb873"> <span class="avatar-u335656-s" role="img" aria-label="johnbbahm">J</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/what-is-going-on-with-earths-longwave-energy-imbalance.1066738/">What is going on with Earth's longwave energy imbalance?</a> </h3> <div class="contentRow-snippet">Observational Assessment of Changes in Earth’s Energy Imbalance Since 2000: 2024 Added greenhouse gases are supposed to be decreasing the OLR.</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/johnbbahm.335656/" class="username " dir="auto" data-user-id="335656" data-xf-init="member-tooltip">johnbbahm</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-11-05T09:24:13-0600" data-time="1730820253" data-date-string="Nov 5, 2024" data-time-string="9:24 AM" title="Nov 5, 2024 at 9:24 AM">Nov 5, 2024</time></li> <li> <dl class="tagList tagList--thread-1066738 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/energy/" data-xf-init="preview-tooltip" data-preview-url="/tags/energy/preview" class="tagItem tagItem--tag_energy" dir="auto"> Energy </a> </span> </dd> </dl> </li> <li>Replies: 0</li> <li>Forum: <a href="/forums/earth-sciences.84/">Earth Sciences</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="hraghav"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/hraghav.745637/" class="avatar avatar--s" data-user-id="745637" data-xf-init="member-tooltip"> <img src="/data/avatars/s/745/745637.jpg?1708153991" srcset="/data/avatars/m/745/745637.jpg?1708153991 2x" alt="hraghav" class="avatar-u745637-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/show-that-the-radius-of-the-exoplanet-is-about-1-2-of-earths-radius.1065838/">Show that the radius of the exoplanet is about 1/2 of Earth’s radius</a> </h3> <div class="contentRow-snippet">TL;DR Summary: For a transiting exoplanet, we find it takes 4.3 days from the start of the transit for the host star to reach a minimum brightness, which lasts for 10 days. Show that the radius of the exoplanet is about 1/2 of Earth’s radius if its orbital radial velocity is 17 m/s. I am...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/hraghav.745637/" class="username " dir="auto" data-user-id="745637" data-xf-init="member-tooltip">hraghav</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-09-22T01:11:49-0500" data-time="1726985509" data-date-string="Sep 22, 2024" data-time-string="1:11 AM" title="Sep 22, 2024 at 1:11 AM">Sep 22, 2024</time></li> <li> <dl class="tagList tagList--thread-1065838 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/exoplanet/" data-xf-init="preview-tooltip" data-preview-url="/tags/exoplanet/preview" class="tagItem tagItem--tag_exoplanet" dir="auto"> Exoplanet </a> <a href="/tags/radius/" data-xf-init="preview-tooltip" data-preview-url="/tags/radius/preview" class="tagItem tagItem--tag_radius" dir="auto"> Radius </a> </span> </dd> </dl> </li> <li>Replies: 2</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Frabjous"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/frabjous.499279/" class="avatar avatar--s" data-user-id="499279" data-xf-init="member-tooltip"> <img src="/data/avatars/s/499/499279.jpg?1683326156" srcset="/data/avatars/m/499/499279.jpg?1683326156 2x" alt="Frabjous" class="avatar-u499279-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/the-earth-is-upgrading-with-a-second-moon.1065798/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>The Earth is upgrading with a second moon</a> </h3> <div class="contentRow-snippet">At least for a little while https://www.sciencealert.com/earth-welcomes-a-new-mini-moon-later-this-month</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/frabjous.499279/" class="username " dir="auto" data-user-id="499279" data-xf-init="member-tooltip">Frabjous</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-09-20T05:33:29-0500" data-time="1726828409" data-date-string="Sep 20, 2024" data-time-string="5:33 AM" title="Sep 20, 2024 at 5:33 AM">Sep 20, 2024</time></li> <li> <dl class="tagList tagList--thread-1065798 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/asteroid/" data-xf-init="preview-tooltip" data-preview-url="/tags/asteroid/preview" class="tagItem tagItem--tag_asteroid" dir="auto"> Asteroid </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/moon/" data-xf-init="preview-tooltip" data-preview-url="/tags/moon/preview" class="tagItem tagItem--tag_moon" dir="auto"> Moon </a> </span> </dd> </dl> </li> <li>Replies: 13</li> <li>Forum: <a href="/forums/astronomy-and-astrophysics.71/">Astronomy and Astrophysics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Jaime Rudas"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/jaime-rudas.662470/" class="avatar avatar--s" data-user-id="662470" data-xf-init="member-tooltip"> <img src="/data/avatars/s/662/662470.jpg?1558717220" srcset="/data/avatars/m/662/662470.jpg?1558717220 2x" alt="Jaime Rudas" class="avatar-u662470-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/what-is-the-radius-of-curvature-of-space-on-earths-surface-due-to-its-mass.1064492/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>What Is the Radius of Curvature of Space on Earth's Surface Due to Its Mass?</a> </h3> <div class="contentRow-snippet">"Matter tells spacetime how to curve, and curved spacetime tells matter how to move" Taking the above into account, the space on the Earth's surface is slightly curved. What is the radius of curvature of space on the Earth's surface due to its mass?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/jaime-rudas.662470/" class="username " dir="auto" data-user-id="662470" data-xf-init="member-tooltip">Jaime Rudas</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-07-21T08:52:09-0500" data-time="1721569929" data-date-string="Jul 21, 2024" data-time-string="8:52 AM" title="Jul 21, 2024 at 8:52 AM">Jul 21, 2024</time></li> <li> <dl class="tagList tagList--thread-1064492 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/curvature/" data-xf-init="preview-tooltip" data-preview-url="/tags/curvature/preview" class="tagItem tagItem--tag_curvature" dir="auto"> Curvature </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/radius/" data-xf-init="preview-tooltip" data-preview-url="/tags/radius/preview" class="tagItem tagItem--tag_radius" dir="auto"> Radius </a> </span> </dd> </dl> </li> <li>Replies: 37</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="ActaPhysica"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/actaphysica.750562/" class="avatar avatar--s" data-user-id="750562" data-xf-init="member-tooltip"> <img src="/data/avatars/s/750/750562.jpg?1720051388" srcset="/data/avatars/m/750/750562.jpg?1720051388 2x" alt="ActaPhysica" class="avatar-u750562-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/return-to-the-center-of-the-earth.1064094/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Return to the center of the Earth</a> </h3> <div class="contentRow-snippet">The usual approach for solving for the time it takes to fall to the center of the earth neglects air resistance & uses Hooke's Law. But if you solve it "the hard way"... Gme*m/r^2 = ma me = 4/3 rho pi r^3 G * 4/3 rho pi r = a separate variables, integrate twice r*Ln(r) - r = 2/3 G rho pi t^2 The...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/actaphysica.750562/" class="username " dir="auto" data-user-id="750562" data-xf-init="member-tooltip">ActaPhysica</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-07-03T19:27:50-0500" data-time="1720052870" data-date-string="Jul 3, 2024" data-time-string="7:27 PM" title="Jul 3, 2024 at 7:27 PM">Jul 3, 2024</time></li> <li> <dl class="tagList tagList--thread-1064094 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/center/" data-xf-init="preview-tooltip" data-preview-url="/tags/center/preview" class="tagItem tagItem--tag_center" dir="auto"> Center </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/falling/" data-xf-init="preview-tooltip" data-preview-url="/tags/falling/preview" class="tagItem tagItem--tag_falling" dir="auto"> Falling </a> </span> </dd> </dl> </li> <li>Replies: 10</li> <li>Forum: <a href="/forums/mechanics.299/">Mechanics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="felizgu"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/felizgu.748577/" class="avatar avatar--s" data-user-id="748577" data-xf-init="member-tooltip"> <img src="/data/avatars/s/748/748577.jpg?1714611279" srcset="/data/avatars/m/748/748577.jpg?1714611279 2x" alt="felizgu" class="avatar-u748577-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-long-for-a-beam-of-light-to-reach-earth.1062322/">How Long for a Beam of Light to Reach Earth?</a> </h3> <div class="contentRow-snippet">TL;DR Summary: This is an astronomy application. Mentor note: Moved from a technical forum section, so the homework template is missing. How long does it take a beam of light to reach Earth from the Sun when the Sun is 93,000,000 miles from Earth? Express your answer in seconds, using...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/felizgu.748577/" class="username " dir="auto" data-user-id="748577" data-xf-init="member-tooltip">felizgu</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-05-01T21:26:01-0500" data-time="1714616761" data-date-string="May 1, 2024" data-time-string="9:26 PM" title="May 1, 2024 at 9:26 PM">May 1, 2024</time></li> <li> <dl class="tagList tagList--thread-1062322 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> Light </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 21</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Hornbein"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/hornbein.489043/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="489043" data-xf-init="member-tooltip" style="background-color: #8585e0; color: #24248f"> <span class="avatar-u489043-s" role="img" aria-label="Hornbein">H</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/quasi-moons.1062218/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Quasi-Moons</a> </h3> <div class="contentRow-snippet">A quasi-moon of Earth is a rock to that orbits both the Earth and Sun with the same solar orbital period as Earth.</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/hornbein.489043/" class="username " dir="auto" data-user-id="489043" data-xf-init="member-tooltip">Hornbein</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-04-28T08:15:11-0500" data-time="1714310111" data-date-string="Apr 28, 2024" data-time-string="8:15 AM" title="Apr 28, 2024 at 8:15 AM">Apr 28, 2024</time></li> <li> <dl class="tagList tagList--thread-1062218 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/sun/" data-xf-init="preview-tooltip" data-preview-url="/tags/sun/preview" class="tagItem tagItem--tag_sun" dir="auto"> Sun </a> </span> </dd> </dl> </li> <li>Replies: 0</li> <li>Forum: <a href="/forums/astronomy-and-astrophysics.71/">Astronomy and Astrophysics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="applied-physics"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/applied-physics.748077/" class="avatar avatar--s" data-user-id="748077" data-xf-init="member-tooltip"> <img src="/data/avatars/s/748/748077.jpg?1713457724" srcset="/data/avatars/m/748/748077.jpg?1713457724 2x" alt="applied-physics" class="avatar-u748077-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/sun-shade-on-earth-ground-is-it-a-straight-line-or-a-curved-line.1061931/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Sun shade on Earth ground, is it a straight line or a curved line?</a> </h3> <div class="contentRow-snippet">How did you find PF?: via Google search Hi, I wonder if the shade from the sun on the ground, on a sunny day, is it a straight line or a curved line?? and if it is curved, how curvature can be calculated ?? Let´s say I have a pole or building, and I can follow up the shade of its top on the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/applied-physics.748077/" class="username " dir="auto" data-user-id="748077" data-xf-init="member-tooltip">applied-physics</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-04-18T11:20:38-0500" data-time="1713457238" data-date-string="Apr 18, 2024" data-time-string="11:20 AM" title="Apr 18, 2024 at 11:20 AM">Apr 18, 2024</time></li> <li> <dl class="tagList tagList--thread-1061931 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/line/" data-xf-init="preview-tooltip" data-preview-url="/tags/line/preview" class="tagItem tagItem--tag_line" dir="auto"> Line </a> <a href="/tags/sun/" data-xf-init="preview-tooltip" data-preview-url="/tags/sun/preview" class="tagItem tagItem--tag_sun" dir="auto"> Sun </a> </span> </dd> </dl> </li> <li>Replies: 3</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="adhd_wonderer"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/adhd_wonderer.746944/" class="avatar avatar--s" data-user-id="746944" data-xf-init="member-tooltip"> <img src="/data/avatars/s/746/746944.jpg?1710951871" srcset="/data/avatars/m/746/746944.jpg?1710951871 2x" alt="adhd_wonderer" class="avatar-u746944-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/can-earth-or-any-spherical-object-in-space-act-as-a-particle-collider.1061067/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Can Earth or any spherical object in space act as a particle collider?</a> </h3> <div class="contentRow-snippet">This is most probably a dumb idea as I'm far from deep physics knowledge but I was thinking. What if Earth is hot inside not because of the pressure and the radioactivity but because it's mass attracts particles (similarly to gravitational lensing) and they collide right in the Earth's center?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/adhd_wonderer.746944/" class="username " dir="auto" data-user-id="746944" data-xf-init="member-tooltip">adhd_wonderer</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-03-20T11:38:34-0500" data-time="1710952714" data-date-string="Mar 20, 2024" data-time-string="11:38 AM" title="Mar 20, 2024 at 11:38 AM">Mar 20, 2024</time></li> <li> <dl class="tagList tagList--thread-1061067 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/object/" data-xf-init="preview-tooltip" data-preview-url="/tags/object/preview" class="tagItem tagItem--tag_object" dir="auto"> object </a> <a href="/tags/spherical/" data-xf-init="preview-tooltip" data-preview-url="/tags/spherical/preview" class="tagItem tagItem--tag_spherical" dir="auto"> Spherical </a> </span> </dd> </dl> </li> <li>Replies: 6</li> <li>Forum: <a href="/forums/other-physics-topics.111/">Other Physics Topics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="marc873a"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/marc873a.745534/" class="avatar avatar--s" data-user-id="745534" data-xf-init="member-tooltip"> <img src="/data/avatars/s/745/745534.jpg?1707827888" srcset="/data/avatars/m/745/745534.jpg?1707827888 2x" alt="marc873a" class="avatar-u745534-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-did-cavendish-find-the-density-of-the-earth.1060833/">How did Cavendish find the density of the Earth?</a> </h3> <div class="contentRow-snippet">I'm trying to find how Cavendish got the density of the earth to 5,48 times the density of water. In all of the YouTube videos and webpages I have seen, they mention different formulas where the mass of the earth or the gravitational constant, G, is included. But as far as I understand, these...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/marc873a.745534/" class="username " dir="auto" data-user-id="745534" data-xf-init="member-tooltip">marc873a</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-03-12T12:03:02-0500" data-time="1710262982" data-date-string="Mar 12, 2024" data-time-string="12:03 PM" title="Mar 12, 2024 at 12:03 PM">Mar 12, 2024</time></li> <li> <dl class="tagList tagList--thread-1060833 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/density/" data-xf-init="preview-tooltip" data-preview-url="/tags/density/preview" class="tagItem tagItem--tag_density" dir="auto"> Density </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> </span> </dd> </dl> </li> <li>Replies: 24</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Trazyn"> <div class="contentRow "> <span class="contentRow-figure"> <span class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="0" style="background-color: #99cc66; color: #406020" title="Trazyn"> <span class="avatar-u0-s" role="img" aria-label="Trazyn">T</span> </span> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/is-the-pastafarian-greeting-rooted-in-earthly-origins.1060095/">Is the Pastafarian Greeting Rooted in Earthly Origins?</a> </h3> <div class="contentRow-snippet">I stretch my tendrils to say hello.</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><span class="username " dir="auto" data-user-id="0">Trazyn</span></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-02-17T08:36:36-0600" data-time="1708180596" data-date-string="Feb 17, 2024" data-time-string="8:36 AM" title="Feb 17, 2024 at 8:36 AM">Feb 17, 2024</time></li> <li> <dl class="tagList tagList--thread-1060095 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/introduction/" data-xf-init="preview-tooltip" data-preview-url="/tags/introduction/preview" class="tagItem tagItem--tag_introduction" dir="auto"> Introduction </a> <a href="/tags/new-member/" data-xf-init="preview-tooltip" data-preview-url="/tags/new-member/preview" class="tagItem tagItem--tag_new-member" dir="auto"> new member </a> </span> </dd> </dl> </li> <li>Replies: 1</li> <li>Forum: <a href="/forums/new-member-introductions.240/">New Member Introductions</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="graphking"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/graphking.686126/" class="avatar avatar--s" data-user-id="686126" data-xf-init="member-tooltip"> <img src="/data/avatars/s/686/686126.jpg?1617421258" srcset="/data/avatars/m/686/686126.jpg?1617421258 2x" alt="graphking" class="avatar-u686126-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/a-strict-proof-of-why-the-earth-is-a-ball.1058413/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>A strict proof of "why the Earth is a ball"</a> </h3> <div class="contentRow-snippet">"bubbles are ball" is called isoperimetric problem in serious mathematic. In this topic, many essay were written. Here's my serious essay about "why earth ball", which has been rejected by arxiv and my mentors...... I would want to know if physicists are interest? I really think that is...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/graphking.686126/" class="username " dir="auto" data-user-id="686126" data-xf-init="member-tooltip">graphking</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-12-21T06:27:57-0600" data-time="1703161677" data-date-string="Dec 21, 2023" data-time-string="6:27 AM" title="Dec 21, 2023 at 6:27 AM">Dec 21, 2023</time></li> <li> <dl class="tagList tagList--thread-1058413 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/ball/" data-xf-init="preview-tooltip" data-preview-url="/tags/ball/preview" class="tagItem tagItem--tag_ball" dir="auto"> Ball </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/proof/" data-xf-init="preview-tooltip" data-preview-url="/tags/proof/preview" class="tagItem tagItem--tag_proof" dir="auto"> Proof </a> </span> </dd> </dl> </li> <li>Replies: 23</li> <li>Forum: <a href="/forums/mechanics.299/">Mechanics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="happyhacker"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/happyhacker.625225/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="625225" data-xf-init="member-tooltip" style="background-color: #7a3d1f; color: #db9470"> <span class="avatar-u625225-s" role="img" aria-label="happyhacker">H</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/consequences-of-a-1-tesla-magnetic-field-coming-into-the-proximity-of-earth.1058077/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Consequences of a 1 Tesla magnetic field coming into the proximity of Earth?</a> </h3> <div class="contentRow-snippet">What would be the consequence if a powerful (1 Tesla) magnetic field came into proximity of Earth? Options open concerning size of generating body and distance. Thank You.</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/happyhacker.625225/" class="username " dir="auto" data-user-id="625225" data-xf-init="member-tooltip">happyhacker</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-12-08T11:08:41-0600" data-time="1702055321" data-date-string="Dec 8, 2023" data-time-string="11:08 AM" title="Dec 8, 2023 at 11:08 AM">Dec 8, 2023</time></li> <li> <dl class="tagList tagList--thread-1058077 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/magnetic-field/" data-xf-init="preview-tooltip" data-preview-url="/tags/magnetic-field/preview" class="tagItem tagItem--tag_magnetic-field" dir="auto"> Magnetic field </a> </span> </dd> </dl> </li> <li>Replies: 11</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="BillTre"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/billtre.581757/" class="avatar avatar--s" data-user-id="581757" data-xf-init="member-tooltip"> <img src="/data/avatars/s/581/581757.jpg?1483504779" srcset="/data/avatars/m/581/581757.jpg?1483504779 2x" alt="BillTre" class="avatar-u581757-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-many-living-cells-on-earth.1057879/">How many living cells on Earth?</a> </h3> <div class="contentRow-snippet">A NY Times article "Exactly How Much Life is on Earth?" (research article here, behind a paywall) says that there are about 1030 cells currently on earth and the total numbers of cells that will be on earth through its future lifespan is about 1041 cells. That is: It was implied in the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/billtre.581757/" class="username " dir="auto" data-user-id="581757" data-xf-init="member-tooltip">BillTre</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-12-02T14:27:30-0600" data-time="1701548850" data-date-string="Dec 2, 2023" data-time-string="2:27 PM" title="Dec 2, 2023 at 2:27 PM">Dec 2, 2023</time></li> <li> <dl class="tagList tagList--thread-1057879 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/biology/" data-xf-init="preview-tooltip" data-preview-url="/tags/biology/preview" class="tagItem tagItem--tag_biology" dir="auto"> Biology </a> <a href="/tags/cells/" data-xf-init="preview-tooltip" data-preview-url="/tags/cells/preview" class="tagItem tagItem--tag_cells" dir="auto"> Cells </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> </span> </dd> </dl> </li> <li>Replies: 1</li> <li>Forum: <a href="/forums/biology-and-medical.82/">Biology and Medical</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="LuisBabboni"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/luisbabboni.682535/" class="avatar avatar--s" data-user-id="682535" data-xf-init="member-tooltip"> <img src="https://secure.gravatar.com/avatar/92f6db795e68c645ff3eaccbe96650b8?s=48" srcset="https://secure.gravatar.com/avatar/92f6db795e68c645ff3eaccbe96650b8?s=96 2x" alt="LuisBabboni" class="avatar-u682535-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/kepler-s-2nd-law-do-any-two-planets-sweep-out-equal-area-in-equal-time.1057516/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Kepler´s 2nd law -- Do any two planets sweep out equal area in equal time?</a> </h3> <div class="contentRow-snippet">I mean. For example, Earth in one month sweep the same area* than Jupiter in one month? *The line joining the Earth with the Sun than the line joining Jupiter with the Sun. I think yes, but is not what 2nd law says. I think in the fact that the aceleration just depends on the distance to the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/luisbabboni.682535/" class="username " dir="auto" data-user-id="682535" data-xf-init="member-tooltip">LuisBabboni</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-11-21T08:01:41-0600" data-time="1700575301" data-date-string="Nov 21, 2023" data-time-string="8:01 AM" title="Nov 21, 2023 at 8:01 AM">Nov 21, 2023</time></li> <li> <dl class="tagList tagList--thread-1057516 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/kepler/" data-xf-init="preview-tooltip" data-preview-url="/tags/kepler/preview" class="tagItem tagItem--tag_kepler" dir="auto"> Kepler </a> <a href="/tags/second-law/" data-xf-init="preview-tooltip" data-preview-url="/tags/second-law/preview" class="tagItem tagItem--tag_second-law" dir="auto"> Second law </a> </span> </dd> </dl> </li> <li>Replies: 11</li> <li>Forum: <a href="/forums/mechanics.299/">Mechanics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="billjohnson"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/billjohnson.740146/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="740146" data-xf-init="member-tooltip" style="background-color: #663333; color: #c38888"> <span class="avatar-u740146-s" role="img" aria-label="billjohnson">B</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-do-we-derive-the-earths-yearly-mean-temperature.1055371/">How do we derive the Earth's yearly mean temperature?</a> </h3> <div class="contentRow-snippet">I'm new to this. I would like to know how we derive the earth's yearly mean temp. I assume there are thermometers all over...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/billjohnson.740146/" class="username " dir="auto" data-user-id="740146" data-xf-init="member-tooltip">billjohnson</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-09-01T16:23:51-0500" data-time="1693603431" data-date-string="Sep 1, 2023" data-time-string="4:23 PM" title="Sep 1, 2023 at 4:23 PM">Sep 1, 2023</time></li> <li> <dl class="tagList tagList--thread-1055371 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/derivation/" data-xf-init="preview-tooltip" data-preview-url="/tags/derivation/preview" class="tagItem tagItem--tag_derivation" dir="auto"> Derivation </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/temperature/" data-xf-init="preview-tooltip" data-preview-url="/tags/temperature/preview" class="tagItem tagItem--tag_temperature" dir="auto"> Temperature </a> </span> </dd> </dl> </li> <li>Replies: 10</li> <li>Forum: <a href="/forums/earth-sciences.84/">Earth Sciences</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="pforeman"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/pforeman.489505/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="489505" data-xf-init="member-tooltip" style="background-color: #5cb8d6; color: #1a5366"> <span class="avatar-u489505-s" role="img" aria-label="pforeman">P</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/supernova-ejection-how-large-are-the-chunks.1054620/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Supernova Ejection: How Large Are the Chunks?</a> </h3> <div class="contentRow-snippet">when a star goes supernova, does it eject out earth, mercury and mars sized chunks. Surely the asteroids that are even the size of Texas won't have enough gravity to compact hard enough to become one chunk. What is the current belief on how large of chunks are ejected from a supernova. Thanks</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/pforeman.489505/" class="username " dir="auto" data-user-id="489505" data-xf-init="member-tooltip">pforeman</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-08-03T18:21:19-0500" data-time="1691104879" data-date-string="Aug 3, 2023" data-time-string="6:21 PM" title="Aug 3, 2023 at 6:21 PM">Aug 3, 2023</time></li> <li> <dl class="tagList tagList--thread-1054620 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/star/" data-xf-init="preview-tooltip" data-preview-url="/tags/star/preview" class="tagItem tagItem--tag_star" dir="auto"> Star </a> </span> </dd> </dl> </li> <li>Replies: 14</li> <li>Forum: <a href="/forums/astronomy-and-astrophysics.71/">Astronomy and Astrophysics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="samm"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/samm.739032/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="739032" data-xf-init="member-tooltip" style="background-color: #66cccc; color: #206060"> <span class="avatar-u739032-s" role="img" aria-label="samm">S</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/is-the-earths-gravitational-pull-constant.1054347/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Is the Earth's gravitational pull constant?</a> </h3> <div class="contentRow-snippet">In the first part, I'm asking about acceleration of freefalling objects with different masses. In the second part I'm asking about acceleration of one object with decreasing distance. Please explain where am I getting it wrong. Thank You!</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/samm.739032/" class="username " dir="auto" data-user-id="739032" data-xf-init="member-tooltip">samm</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-07-26T00:58:42-0500" data-time="1690351122" data-date-string="Jul 26, 2023" data-time-string="12:58 AM" title="Jul 26, 2023 at 12:58 AM">Jul 26, 2023</time></li> <li> <dl class="tagList tagList--thread-1054347 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/constant/" data-xf-init="preview-tooltip" data-preview-url="/tags/constant/preview" class="tagItem tagItem--tag_constant" dir="auto"> Constant </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> </span> </dd> </dl> </li> <li>Replies: 7</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="earthlingjeff"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/earthlingjeff.738334/" class="avatar avatar--s" data-user-id="738334" data-xf-init="member-tooltip"> <img src="/data/avatars/s/738/738334.jpg?1688606491" srcset="/data/avatars/m/738/738334.jpg?1688606491 2x" alt="earthlingjeff" class="avatar-u738334-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/would-earth-not-be-seen-flashing-from-space-like-a-lighthouse.1053827/">Would Earth not be seen flashing from space like a lighthouse?</a> </h3> <div class="contentRow-snippet">Can anyone tell me if this would be correct? Would Earth not be seen flashing from space like a lighthouse to a distant planet when it reflects oceans and then DMS as the sons reflection per perspective travels across land then back to Ocean then back to land? I'm sure it probably says that...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/earthlingjeff.738334/" class="username " dir="auto" data-user-id="738334" data-xf-init="member-tooltip">earthlingjeff</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-07-05T20:21:34-0500" data-time="1688606494" data-date-string="Jul 5, 2023" data-time-string="8:21 PM" title="Jul 5, 2023 at 8:21 PM">Jul 5, 2023</time></li> <li> <dl class="tagList tagList--thread-1053827 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/space/" data-xf-init="preview-tooltip" data-preview-url="/tags/space/preview" class="tagItem tagItem--tag_space" dir="auto"> Space </a> </span> </dd> </dl> </li> <li>Replies: 9</li> <li>Forum: <a href="/forums/aerospace-engineering.288/">Aerospace Engineering</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Lotto"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/lotto.730412/" class="avatar avatar--s" data-user-id="730412" data-xf-init="member-tooltip"> <img src="/data/avatars/s/730/730412.jpg?1678812283" srcset="/data/avatars/m/730/730412.jpg?1678812283 2x" alt="Lotto" class="avatar-u730412-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/what-is-the-total-kinetic-energy-of-the-earth-relative-to-the-sun.1053754/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>What is the total kinetic energy of the Earth relative to the Sun?</a> </h3> <div class="contentRow-snippet">Because it rotates around its axis, then it has a rotational kinetic energy. But when it orbits the Sun, then it has an another rotational energy too. Would it be ##E_\mathrm{rot} = \frac 12 (\frac 25 MR^2+ Md^2) {\omega}^2 ##, where ##d## is the distance between the Sun and the Earth. I...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/lotto.730412/" class="username " dir="auto" data-user-id="730412" data-xf-init="member-tooltip">Lotto</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-07-03T15:45:07-0500" data-time="1688417107" data-date-string="Jul 3, 2023" data-time-string="3:45 PM" title="Jul 3, 2023 at 3:45 PM">Jul 3, 2023</time></li> <li> <dl class="tagList tagList--thread-1053754 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/rotational-energy/" data-xf-init="preview-tooltip" data-preview-url="/tags/rotational-energy/preview" class="tagItem tagItem--tag_rotational-energy" dir="auto"> Rotational energy </a> <a href="/tags/rotational-motion/" data-xf-init="preview-tooltip" data-preview-url="/tags/rotational-motion/preview" class="tagItem tagItem--tag_rotational-motion" dir="auto"> Rotational motion </a> </span> </dd> </dl> </li> <li>Replies: 40</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Hornbein"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/hornbein.489043/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="489043" data-xf-init="member-tooltip" style="background-color: #8585e0; color: #24248f"> <span class="avatar-u489043-s" role="img" aria-label="Hornbein">H</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/a-4d-hyperearth-1000x-more-space-for-real-estate.1052374/">A 4D HyperEarth: 1000x More Space for Real Estate</a> </h3> <div class="contentRow-snippet">Let’s dubiously assume that these 4D atoms would have the same radius as 3D atoms. Let’s further dubiously assume that a 4D HyperEarth has the same number of atoms as 3D Earth. Then the diameter of HyperEarth would be less than a kilometer. Four dimensional Earth is much more compact. Wouldn’t...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/hornbein.489043/" class="username " dir="auto" data-user-id="489043" data-xf-init="member-tooltip">Hornbein</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-05-11T23:21:49-0500" data-time="1683865309" data-date-string="May 11, 2023" data-time-string="11:21 PM" title="May 11, 2023 at 11:21 PM">May 11, 2023</time></li> <li> <dl class="tagList tagList--thread-1052374 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/4d/" data-xf-init="preview-tooltip" data-preview-url="/tags/4d/preview" class="tagItem tagItem--tag_4d" dir="auto"> 4d </a> <a href="/tags/atoms/" data-xf-init="preview-tooltip" data-preview-url="/tags/atoms/preview" class="tagItem tagItem--tag_atoms" dir="auto"> Atoms </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> </span> </dd> </dl> </li> <li>Replies: 11</li> <li>Forum: <a href="/forums/sci-fi-writing-and-world-building.220/">Sci-Fi Writing and World Building</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="syfry"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/syfry.735430/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="735430" data-xf-init="member-tooltip" style="background-color: #cc3366; color: #f0c2d1"> <span class="avatar-u735430-s" role="img" aria-label="syfry">S</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/does-the-inverse-square-law-equalize-gravity-at-different-spots.1052318/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Does the inverse square law equalize gravity at different spots?</a> </h3> <div class="contentRow-snippet">Inverse square law would reduce the gravity from the parts of Earth that are farthest from our feet. It'll also reduce the gravity from Earth's center by a lesser amount, but would that be lesser enough so the gravity 20 kilometers under our feet is stronger than the core's gravity or even the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/syfry.735430/" class="username " dir="auto" data-user-id="735430" data-xf-init="member-tooltip">syfry</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-05-10T02:16:36-0500" data-time="1683702996" data-date-string="May 10, 2023" data-time-string="2:16 AM" title="May 10, 2023 at 2:16 AM">May 10, 2023</time></li> <li> <dl class="tagList tagList--thread-1052318 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/center-of-mass/" data-xf-init="preview-tooltip" data-preview-url="/tags/center-of-mass/preview" class="tagItem tagItem--tag_center-of-mass" dir="auto"> Center of mass </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/gravity/" data-xf-init="preview-tooltip" data-preview-url="/tags/gravity/preview" class="tagItem tagItem--tag_gravity" dir="auto"> Gravity </a> <a href="/tags/inverse/" data-xf-init="preview-tooltip" data-preview-url="/tags/inverse/preview" class="tagItem tagItem--tag_inverse" dir="auto"> Inverse </a> <a href="/tags/inverse-square-law/" data-xf-init="preview-tooltip" data-preview-url="/tags/inverse-square-law/preview" class="tagItem tagItem--tag_inverse-square-law" dir="auto"> Inverse square law </a> <a href="/tags/law/" data-xf-init="preview-tooltip" data-preview-url="/tags/law/preview" class="tagItem tagItem--tag_law" dir="auto"> Law </a> <a href="/tags/square/" data-xf-init="preview-tooltip" data-preview-url="/tags/square/preview" class="tagItem tagItem--tag_square" dir="auto"> Square </a> </span> </dd> </dl> </li> <li>Replies: 8</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Asem"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/asem.734186/" class="avatar avatar--s" data-user-id="734186" data-xf-init="member-tooltip"> <img src="/data/avatars/s/734/734186.jpg?1678982979" srcset="/data/avatars/m/734/734186.jpg?1678982979 2x" alt="Asem" class="avatar-u734186-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/angular-velocity-of-a-large-pendulum-on-earth-as-seen-from-the-stars.1052263/">Angular Velocity of a Large Pendulum on Earth as seen from the stars</a> </h3> <div class="contentRow-snippet">I don't understand the question. how am I supposed to find the magnitudes and directions of the velocity from the figure?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/asem.734186/" class="username " dir="auto" data-user-id="734186" data-xf-init="member-tooltip">Asem</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-05-07T13:33:42-0500" data-time="1683484422" data-date-string="May 7, 2023" data-time-string="1:33 PM" title="May 7, 2023 at 1:33 PM">May 7, 2023</time></li> <li> <dl class="tagList tagList--thread-1052263 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/angular/" data-xf-init="preview-tooltip" data-preview-url="/tags/angular/preview" class="tagItem tagItem--tag_angular" dir="auto"> Angular </a> <a href="/tags/angular-velocity/" data-xf-init="preview-tooltip" data-preview-url="/tags/angular-velocity/preview" class="tagItem tagItem--tag_angular-velocity" dir="auto"> Angular velocity </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/pendulum/" data-xf-init="preview-tooltip" data-preview-url="/tags/pendulum/preview" class="tagItem tagItem--tag_pendulum" dir="auto"> Pendulum </a> <a href="/tags/stars/" data-xf-init="preview-tooltip" data-preview-url="/tags/stars/preview" class="tagItem tagItem--tag_stars" dir="auto"> Stars </a> <a href="/tags/velocity/" data-xf-init="preview-tooltip" data-preview-url="/tags/velocity/preview" class="tagItem tagItem--tag_velocity" dir="auto"> Velocity </a> </span> </dd> </dl> </li> <li>Replies: 11</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Lotto"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/lotto.730412/" class="avatar avatar--s" data-user-id="730412" data-xf-init="member-tooltip"> <img src="/data/avatars/s/730/730412.jpg?1678812283" srcset="/data/avatars/m/730/730412.jpg?1678812283 2x" alt="Lotto" class="avatar-u730412-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/what-is-meant-by-upper-limit-of-work-done-on-earth.1051698/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>What is meant by "upper limit of work done on Earth"?</a> </h3> <div class="contentRow-snippet">I think that the work is meant to be work done for instance in power stations. Or is it similar to work I do on a body when I lift it for example? But how can we then do that work on our Earth? I just need to understand the task, otherwise I want to solve it myself. The problem involves...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/lotto.730412/" class="username " dir="auto" data-user-id="730412" data-xf-init="member-tooltip">Lotto</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-04-16T14:29:17-0500" data-time="1681673357" data-date-string="Apr 16, 2023" data-time-string="2:29 PM" title="Apr 16, 2023 at 2:29 PM">Apr 16, 2023</time></li> <li> <dl class="tagList tagList--thread-1051698 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/limit/" data-xf-init="preview-tooltip" data-preview-url="/tags/limit/preview" class="tagItem tagItem--tag_limit" dir="auto"> Limit </a> <a href="/tags/termodynamics/" data-xf-init="preview-tooltip" data-preview-url="/tags/termodynamics/preview" class="tagItem tagItem--tag_termodynamics" dir="auto"> Termodynamics </a> <a href="/tags/work/" data-xf-init="preview-tooltip" data-preview-url="/tags/work/preview" class="tagItem tagItem--tag_work" dir="auto"> Work </a> <a href="/tags/work-and-energy/" data-xf-init="preview-tooltip" data-preview-url="/tags/work-and-energy/preview" class="tagItem tagItem--tag_work-and-energy" dir="auto"> Work and energy </a> <a href="/tags/work-done/" data-xf-init="preview-tooltip" data-preview-url="/tags/work-done/preview" class="tagItem tagItem--tag_work-done" dir="auto"> Work done </a> </span> </dd> </dl> </li> <li>Replies: 7</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="emily-"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/emily.733484/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="733484" data-xf-init="member-tooltip" style="background-color: #cc66cc; color: #602060"> <span class="avatar-u733484-s" role="img" aria-label="emily-">E</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-to-calculate-earth-speed-of-the-moon-induced-orbit.1050909/">How to calculate Earth speed of the Moon induced orbit?</a> </h3> <div class="contentRow-snippet">It didn't work and I don't know how to do it.</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/emily.733484/" class="username " dir="auto" data-user-id="733484" data-xf-init="member-tooltip">emily-</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-03-18T17:09:54-0500" data-time="1679177394" data-date-string="Mar 18, 2023" data-time-string="5:09 PM" title="Mar 18, 2023 at 5:09 PM">Mar 18, 2023</time></li> <li> <dl class="tagList tagList--thread-1050909 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/gravity/" data-xf-init="preview-tooltip" data-preview-url="/tags/gravity/preview" class="tagItem tagItem--tag_gravity" dir="auto"> Gravity </a> <a href="/tags/induced/" data-xf-init="preview-tooltip" data-preview-url="/tags/induced/preview" class="tagItem tagItem--tag_induced" dir="auto"> Induced </a> <a href="/tags/moon/" data-xf-init="preview-tooltip" data-preview-url="/tags/moon/preview" class="tagItem tagItem--tag_moon" dir="auto"> Moon </a> <a href="/tags/orbit/" data-xf-init="preview-tooltip" data-preview-url="/tags/orbit/preview" class="tagItem tagItem--tag_orbit" dir="auto"> Orbit </a> <a href="/tags/physcis/" data-xf-init="preview-tooltip" data-preview-url="/tags/physcis/preview" class="tagItem tagItem--tag_physcis" dir="auto"> Physcis </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> <a href="/tags/velocity/" data-xf-init="preview-tooltip" data-preview-url="/tags/velocity/preview" class="tagItem tagItem--tag_velocity" dir="auto"> Velocity </a> </span> </dd> </dl> </li> <li>Replies: 4</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="tonyeveland"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/tonyeveland.734121/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="734121" data-xf-init="member-tooltip" style="background-color: #e08585; color: #8f2424"> <span class="avatar-u734121-s" role="img" aria-label="tonyeveland">T</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/does-anyone-have-a-table-of-earth-mean-temperatures.1050589/">Does anyone have a table of Earth mean temperatures?</a> </h3> <div class="contentRow-snippet">I would like a table of Earth mean temperatures going back as far as available. Where can I find that?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/tonyeveland.734121/" class="username " dir="auto" data-user-id="734121" data-xf-init="member-tooltip">tonyeveland</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-03-08T01:20:30-0600" data-time="1678260030" data-date-string="Mar 8, 2023" data-time-string="1:20 AM" title="Mar 8, 2023 at 1:20 AM">Mar 8, 2023</time></li> <li> <dl class="tagList tagList--thread-1050589 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/mean/" data-xf-init="preview-tooltip" data-preview-url="/tags/mean/preview" class="tagItem tagItem--tag_mean" dir="auto"> Mean </a> <a href="/tags/table/" data-xf-init="preview-tooltip" data-preview-url="/tags/table/preview" class="tagItem tagItem--tag_table" dir="auto"> Table </a> </span> </dd> </dl> </li> <li>Replies: 8</li> <li>Forum: <a href="/forums/earth-sciences.84/">Earth Sciences</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Neitrino"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/neitrino.28556/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="28556" data-xf-init="member-tooltip" style="background-color: #cc33cc; color: #3d0f3d"> <span class="avatar-u28556-s" role="img" aria-label="Neitrino">N</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/earth-ground-meter-vs-multimeter.1049943/">Earth ground meter Vs Multimeter</a> </h3> <div class="contentRow-snippet">Dear forum please help me with the following understanding: There is (are) such equipment Earth ground testers (https://www.fluke.com/en/products/electrical-testi...) - it is used to measure grounded electrical systems or to measure. Such equipment is having multiple poles that are attached to...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/neitrino.28556/" class="username " dir="auto" data-user-id="28556" data-xf-init="member-tooltip">Neitrino</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-02-13T11:14:01-0600" data-time="1676308441" data-date-string="Feb 13, 2023" data-time-string="11:14 AM" title="Feb 13, 2023 at 11:14 AM">Feb 13, 2023</time></li> <li> <dl class="tagList tagList--thread-1049943 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/ground/" data-xf-init="preview-tooltip" data-preview-url="/tags/ground/preview" class="tagItem tagItem--tag_ground" dir="auto"> Ground </a> <a href="/tags/meter/" data-xf-init="preview-tooltip" data-preview-url="/tags/meter/preview" class="tagItem tagItem--tag_meter" dir="auto"> Meter </a> <a href="/tags/multimeter/" data-xf-init="preview-tooltip" data-preview-url="/tags/multimeter/preview" class="tagItem tagItem--tag_multimeter" dir="auto"> Multimeter </a> </span> </dd> </dl> </li> <li>Replies: 1</li> <li>Forum: <a href="/forums/electrical-engineering.102/">Electrical Engineering</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="EclogiteFacies"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/eclogitefacies.685612/" class="avatar avatar--s" data-user-id="685612" data-xf-init="member-tooltip"> <img src="/data/avatars/s/685/685612.jpg?1609173875" srcset="/data/avatars/m/685/685612.jpg?1609173875 2x" alt="EclogiteFacies" class="avatar-u685612-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-meaningful-is-the-notion-of-now-here-on-earth.1049545/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>How meaningful is the notion of now here on Earth?</a> </h3> <div class="contentRow-snippet">So, not looking for anything over complicated. Just been picking up some special relativity. How meaningful is the notion of now here on Earth? Is special relativity worth even considering for day to day interactions with others?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/eclogitefacies.685612/" class="username " dir="auto" data-user-id="685612" data-xf-init="member-tooltip">EclogiteFacies</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-01-30T09:11:36-0600" data-time="1675091496" data-date-string="Jan 30, 2023" data-time-string="9:11 AM" title="Jan 30, 2023 at 9:11 AM">Jan 30, 2023</time></li> <li> <dl class="tagList tagList--thread-1049545 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> </span> </dd> </dl> </li> <li>Replies: 1</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="DANIELWR1998"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/danielwr1998.732746/" class="avatar avatar--s" data-user-id="732746" data-xf-init="member-tooltip"> <img src="/data/avatars/s/732/732746.jpg?1674480837" srcset="/data/avatars/m/732/732746.jpg?1674480837 2x" alt="DANIELWR1998" class="avatar-u732746-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-do-i-find-way-of-comparing-the-density-of-the-earth-and-the-moon.1049348/">How do I find way of comparing the density of the Earth and the Moon?</a> </h3> <div class="contentRow-snippet">Surface acceleration is proportional to density and radius of planet (as 2 powers of R cancel with the volume) g(moon)/g(earth) = density(moon)*radius(moon)/density (earth)*radius(earth) = (1/4)*density(moon)/density(earth)</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/danielwr1998.732746/" class="username " dir="auto" data-user-id="732746" data-xf-init="member-tooltip">DANIELWR1998</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-01-24T12:46:39-0600" data-time="1674585999" data-date-string="Jan 24, 2023" data-time-string="12:46 PM" title="Jan 24, 2023 at 12:46 PM">Jan 24, 2023</time></li> <li> <dl class="tagList tagList--thread-1049348 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/centripetal/" data-xf-init="preview-tooltip" data-preview-url="/tags/centripetal/preview" class="tagItem tagItem--tag_centripetal" dir="auto"> Centripetal </a> <a href="/tags/density/" data-xf-init="preview-tooltip" data-preview-url="/tags/density/preview" class="tagItem tagItem--tag_density" dir="auto"> Density </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/gravity/" data-xf-init="preview-tooltip" data-preview-url="/tags/gravity/preview" class="tagItem tagItem--tag_gravity" dir="auto"> Gravity </a> <a href="/tags/moon/" data-xf-init="preview-tooltip" data-preview-url="/tags/moon/preview" class="tagItem tagItem--tag_moon" dir="auto"> Moon </a> <a href="/tags/orbital-period/" data-xf-init="preview-tooltip" data-preview-url="/tags/orbital-period/preview" class="tagItem tagItem--tag_orbital-period" dir="auto"> Orbital period </a> </span> </dd> </dl> </li> <li>Replies: 9</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="James1238765"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/james1238765.731900/" class="avatar avatar--s" data-user-id="731900" data-xf-init="member-tooltip"> <img src="/data/avatars/s/731/731900.jpg?1671747161" srcset="/data/avatars/m/731/731900.jpg?1671747161 2x" alt="James1238765" class="avatar-u731900-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/modeling-the-earth-and-sun-2-body-orbits-using-general-relativity.1049299/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Modeling the Earth and Sun (2 body orbits) using general relativity?</a> </h3> <div class="contentRow-snippet">Modeling the time evolution of the sun and earth orbiting each other using ##F = \frac{GMm}{r^2}## is straightforward. However, it appears that modeling the time evolution of the same 2 body system using general relativity seems to be a hard/intractable problem? There was in depth discussion by...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/james1238765.731900/" class="username " dir="auto" data-user-id="731900" data-xf-init="member-tooltip">James1238765</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-01-23T05:24:14-0600" data-time="1674473054" data-date-string="Jan 23, 2023" data-time-string="5:24 AM" title="Jan 23, 2023 at 5:24 AM">Jan 23, 2023</time></li> <li> <dl class="tagList tagList--thread-1049299 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/body/" data-xf-init="preview-tooltip" data-preview-url="/tags/body/preview" class="tagItem tagItem--tag_body" dir="auto"> Body </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/general/" data-xf-init="preview-tooltip" data-preview-url="/tags/general/preview" class="tagItem tagItem--tag_general" dir="auto"> General </a> <a href="/tags/general-relativity/" data-xf-init="preview-tooltip" data-preview-url="/tags/general-relativity/preview" class="tagItem tagItem--tag_general-relativity" dir="auto"> General relativity </a> <a href="/tags/modeling/" data-xf-init="preview-tooltip" data-preview-url="/tags/modeling/preview" class="tagItem tagItem--tag_modeling" dir="auto"> Modeling </a> <a href="/tags/multibody/" data-xf-init="preview-tooltip" data-preview-url="/tags/multibody/preview" class="tagItem tagItem--tag_multibody" dir="auto"> multibody </a> <a href="/tags/orbit/" data-xf-init="preview-tooltip" data-preview-url="/tags/orbit/preview" class="tagItem tagItem--tag_orbit" dir="auto"> Orbit </a> <a href="/tags/orbits/" data-xf-init="preview-tooltip" data-preview-url="/tags/orbits/preview" class="tagItem tagItem--tag_orbits" dir="auto"> Orbits </a> <a href="/tags/relativity/" data-xf-init="preview-tooltip" data-preview-url="/tags/relativity/preview" class="tagItem tagItem--tag_relativity" dir="auto"> Relativity </a> <a href="/tags/sun/" data-xf-init="preview-tooltip" data-preview-url="/tags/sun/preview" class="tagItem tagItem--tag_sun" dir="auto"> Sun </a> </span> </dd> </dl> </li> <li>Replies: 62</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Shirish"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/shirish.647247/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="647247" data-xf-init="member-tooltip" style="background-color: #669933; color: #0d1306"> <span class="avatar-u647247-s" role="img" aria-label="Shirish">S</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/calc-excess-rad-on-earth-in-curved-3d-space-feynman-lectures-6-2.1049185/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Calc Excess Rad on Earth in Curved 3D Space | Feynman Lectures 6-2</a> </h3> <div class="contentRow-snippet">I'm reading the Feynman lectures chapter on "Curved Space", section 6-2. Say we're trying to figure out a way to measure average curvature on Earth. We know that 3d space is curved if Euclidean geometry rules don't work - e.g. the ratio of circumference and radius of a circle isn't ##2\pi##, or...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/shirish.647247/" class="username " dir="auto" data-user-id="647247" data-xf-init="member-tooltip">Shirish</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2023-01-19T08:19:59-0600" data-time="1674137999" data-date-string="Jan 19, 2023" data-time-string="8:19 AM" title="Jan 19, 2023 at 8:19 AM">Jan 19, 2023</time></li> <li> <dl class="tagList tagList--thread-1049185 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/3d/" data-xf-init="preview-tooltip" data-preview-url="/tags/3d/preview" class="tagItem tagItem--tag_3d" dir="auto"> 3d </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/radius/" data-xf-init="preview-tooltip" data-preview-url="/tags/radius/preview" class="tagItem tagItem--tag_radius" dir="auto"> Radius </a> <a href="/tags/space/" data-xf-init="preview-tooltip" data-preview-url="/tags/space/preview" class="tagItem tagItem--tag_space" dir="auto"> Space </a> </span> </dd> </dl> </li> <li>Replies: 29</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Astronuc"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/astronuc.15685/" class="avatar avatar--s" data-user-id="15685" data-xf-init="member-tooltip"> <img src="/data/avatars/s/15/15685.jpg?1431188715" alt="Astronuc" class="avatar-u15685-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/coldest-place-on-earth-in-antarctica-of-course.1048346/">Coldest Place on Earth - in Antarctica, of course</a> </h3> <div class="contentRow-snippet">What’s the coldest spot on Earth? NASA has pinpointed it — and the nights are deadly https://www.yahoo.com/news/coldest-spot-earth-nasa-pinpointed-125903009.html</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/astronuc.15685/" class="username " dir="auto" data-user-id="15685" data-xf-init="member-tooltip">Astronuc</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-12-19T11:10:49-0600" data-time="1671469849" data-date-string="Dec 19, 2022" data-time-string="11:10 AM" title="Dec 19, 2022 at 11:10 AM">Dec 19, 2022</time></li> <li> <dl class="tagList tagList--thread-1048346 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/course/" data-xf-init="preview-tooltip" data-preview-url="/tags/course/preview" class="tagItem tagItem--tag_course" dir="auto"> Course </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> </span> </dd> </dl> </li> <li>Replies: 5</li> <li>Forum: <a href="/forums/earth-sciences.84/">Earth Sciences</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Gaylan Larson"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/gaylan-larson.731545/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="731545" data-xf-init="member-tooltip" style="background-color: #5cd6b8; color: #1a6653"> <span class="avatar-u731545-s" role="img" aria-label="Gaylan Larson">G</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-did-earth-get-so-far-away-from-other-galaxies.1048042/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>How did Earth get so far away from other galaxies?</a> </h3> <div class="contentRow-snippet">If the Big Bang happened 13.6 billion years ago how can the James Webb telescope now see galaxies 13.3 billion light years away? 13.3 billion years ago the universe was 0.3 billion years old. How large was the universe at that time? If physical mater traveled in all directions from the point...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/gaylan-larson.731545/" class="username " dir="auto" data-user-id="731545" data-xf-init="member-tooltip">Gaylan Larson</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-12-10T14:56:34-0600" data-time="1670705794" data-date-string="Dec 10, 2022" data-time-string="2:56 PM" title="Dec 10, 2022 at 2:56 PM">Dec 10, 2022</time></li> <li> <dl class="tagList tagList--thread-1048042 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/galaxies/" data-xf-init="preview-tooltip" data-preview-url="/tags/galaxies/preview" class="tagItem tagItem--tag_galaxies" dir="auto"> Galaxies </a> </span> </dd> </dl> </li> <li>Replies: 12</li> <li>Forum: <a href="/forums/astronomy-and-astrophysics.71/">Astronomy and Astrophysics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Zoubayr"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/zoubayr.731314/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="731314" data-xf-init="member-tooltip" style="background-color: #cc5233; color: #3d180f"> <span class="avatar-u731314-s" role="img" aria-label="Zoubayr">Z</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/angular-deceleration-of-the-earth.1047866/">Angular deceleration of the Earth</a> </h3> <div class="contentRow-snippet">365 rotations - 365 days 365 days - 31536000 s apart from that I do not know how to continue the question</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/zoubayr.731314/" class="username " dir="auto" data-user-id="731314" data-xf-init="member-tooltip">Zoubayr</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-12-05T10:15:03-0600" data-time="1670256903" data-date-string="Dec 5, 2022" data-time-string="10:15 AM" title="Dec 5, 2022 at 10:15 AM">Dec 5, 2022</time></li> <li> <dl class="tagList tagList--thread-1047866 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/angular/" data-xf-init="preview-tooltip" data-preview-url="/tags/angular/preview" class="tagItem tagItem--tag_angular" dir="auto"> Angular </a> <a href="/tags/deceleration/" data-xf-init="preview-tooltip" data-preview-url="/tags/deceleration/preview" class="tagItem tagItem--tag_deceleration" dir="auto"> Deceleration </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> </span> </dd> </dl> </li> <li>Replies: 52</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="DaveC426913"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/davec426913.15808/" class="avatar avatar--s" data-user-id="15808" data-xf-init="member-tooltip"> <img src="/data/avatars/s/15/15808.jpg?1431188719" alt="DaveC426913" class="avatar-u15808-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-much-time-passes-on-earth.1047670/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>How much time passes on Earth?</a> </h3> <div class="contentRow-snippet">The recent threads about relativity and the (ersatz) twin paradox got me flummoxed (again). I referenced a story (A World Out of Time) where the man character came back to an Earth that was 3 million years older than when he left. The reason is that he journeyed to the galactic centre and back...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/davec426913.15808/" class="username " dir="auto" data-user-id="15808" data-xf-init="member-tooltip">DaveC426913</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-11-29T12:42:48-0600" data-time="1669747368" data-date-string="Nov 29, 2022" data-time-string="12:42 PM" title="Nov 29, 2022 at 12:42 PM">Nov 29, 2022</time></li> <li> <dl class="tagList tagList--thread-1047670 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/time/" data-xf-init="preview-tooltip" data-preview-url="/tags/time/preview" class="tagItem tagItem--tag_time" dir="auto"> Time </a> </span> </dd> </dl> </li> <li>Replies: 9</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Lotto"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/lotto.730412/" class="avatar avatar--s" data-user-id="730412" data-xf-init="member-tooltip"> <img src="/data/avatars/s/730/730412.jpg?1678812283" srcset="/data/avatars/m/730/730412.jpg?1678812283 2x" alt="Lotto" class="avatar-u730412-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/time-dilation-what-is-the-time-on-the-earth.1047649/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Time dilation - what is the time on the Earth?</a> </h3> <div class="contentRow-snippet">If I understand it well, 10 s did really passed in the rocket, it is according to the observer on the Earth, but if the man in the rocket measured the time, he would measure 10 s. But when we say that the man in the rocket is in an inertial frame of reference as well, he can claim that because...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/lotto.730412/" class="username " dir="auto" data-user-id="730412" data-xf-init="member-tooltip">Lotto</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-11-28T15:38:49-0600" data-time="1669671529" data-date-string="Nov 28, 2022" data-time-string="3:38 PM" title="Nov 28, 2022 at 3:38 PM">Nov 28, 2022</time></li> <li> <dl class="tagList tagList--thread-1047649 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/dilation/" data-xf-init="preview-tooltip" data-preview-url="/tags/dilation/preview" class="tagItem tagItem--tag_dilation" dir="auto"> Dilation </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/time/" data-xf-init="preview-tooltip" data-preview-url="/tags/time/preview" class="tagItem tagItem--tag_time" dir="auto"> Time </a> <a href="/tags/time-dilation/" data-xf-init="preview-tooltip" data-preview-url="/tags/time-dilation/preview" class="tagItem tagItem--tag_time-dilation" dir="auto"> Time dilation </a> </span> </dd> </dl> </li> <li>Replies: 32</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="babaliaris"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/babaliaris.649256/" class="avatar avatar--s" data-user-id="649256" data-xf-init="member-tooltip"> <img src="/data/avatars/s/649/649256.jpg?1533626800" srcset="/data/avatars/m/649/649256.jpg?1533626800 2x" alt="babaliaris" class="avatar-u649256-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-does-earth-ground-absorb-electric-current.1047300/">How does Earth Ground "absorb" electric current?</a> </h3> <div class="contentRow-snippet">This is a topic that almost no one can actually explain from what I found on the internet. This answer https://physics.stackexchange.com/questions/74625/does-alternating-current-ac-require-a-complete-circuit/74999#74999 is the closest I found so far. The idea is how the grounded neutral...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/babaliaris.649256/" class="username " dir="auto" data-user-id="649256" data-xf-init="member-tooltip">babaliaris</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-11-16T08:02:20-0600" data-time="1668607340" data-date-string="Nov 16, 2022" data-time-string="8:02 AM" title="Nov 16, 2022 at 8:02 AM">Nov 16, 2022</time></li> <li> <dl class="tagList tagList--thread-1047300 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/current/" data-xf-init="preview-tooltip" data-preview-url="/tags/current/preview" class="tagItem tagItem--tag_current" dir="auto"> Current </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/electric/" data-xf-init="preview-tooltip" data-preview-url="/tags/electric/preview" class="tagItem tagItem--tag_electric" dir="auto"> Electric </a> <a href="/tags/electric-current/" data-xf-init="preview-tooltip" data-preview-url="/tags/electric-current/preview" class="tagItem tagItem--tag_electric-current" dir="auto"> Electric current </a> <a href="/tags/ground/" data-xf-init="preview-tooltip" data-preview-url="/tags/ground/preview" class="tagItem tagItem--tag_ground" dir="auto"> Ground </a> </span> </dd> </dl> </li> <li>Replies: 12</li> <li>Forum: <a href="/forums/electrical-engineering.102/">Electrical Engineering</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="accdd"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/accdd.700245/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="700245" data-xf-init="member-tooltip" style="background-color: #145233; color: #47d18c"> <span class="avatar-u700245-s" role="img" aria-label="accdd">A</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/what-color-do-mirrors-on-earth-appear-from-space.1046738/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>What Color Do Mirrors on Earth Appear from Space?</a> </h3> <div class="contentRow-snippet">If I place a mirror on the ground facing upward, what color will those who observe it from space see?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/accdd.700245/" class="username " dir="auto" data-user-id="700245" data-xf-init="member-tooltip">accdd</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-10-26T13:50:57-0500" data-time="1666810257" data-date-string="Oct 26, 2022" data-time-string="1:50 PM" title="Oct 26, 2022 at 1:50 PM">Oct 26, 2022</time></li> <li> <dl class="tagList tagList--thread-1046738 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/color/" data-xf-init="preview-tooltip" data-preview-url="/tags/color/preview" class="tagItem tagItem--tag_color" dir="auto"> Color </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/mirror/" data-xf-init="preview-tooltip" data-preview-url="/tags/mirror/preview" class="tagItem tagItem--tag_mirror" dir="auto"> Mirror </a> </span> </dd> </dl> </li> <li>Replies: 35</li> <li>Forum: <a href="/forums/other-physics-topics.111/">Other Physics Topics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Gear300"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/gear300.81703/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="81703" data-xf-init="member-tooltip" style="background-color: #9999cc; color: #3c3c77"> <span class="avatar-u81703-s" role="img" aria-label="Gear300">G</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/where-is-general-relativity-applied-and-when-does-the-oblate-earth-matter.1046063/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Where is General Relativity Applied and When Does the Oblate Earth Matter?</a> </h3> <div class="contentRow-snippet">This is actually two questions. They are In which courses or field work is general relativity taught as method and not philosophy? At which altitudes does the oblate Earth approximation matter? At stealth bomber altitudes? Somewhere between Earth and Moon (in perhaps inertial gyroscope...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/gear300.81703/" class="username " dir="auto" data-user-id="81703" data-xf-init="member-tooltip">Gear300</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-10-02T07:54:32-0500" data-time="1664715272" data-date-string="Oct 2, 2022" data-time-string="7:54 AM" title="Oct 2, 2022 at 7:54 AM">Oct 2, 2022</time></li> <li> <dl class="tagList tagList--thread-1046063 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> </span> </dd> </dl> </li> <li>Replies: 5</li> <li>Forum: <a href="/forums/astronomy-and-astrophysics.71/">Astronomy and Astrophysics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Sciencemaster"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/sciencemaster.684428/" class="avatar avatar--s" data-user-id="684428" data-xf-init="member-tooltip"> <img src="/data/avatars/s/684/684428.jpg?1606704931" srcset="/data/avatars/m/684/684428.jpg?1606704931 2x" alt="Sciencemaster" class="avatar-u684428-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/database-of-binary-star-data-info-within-10-pc-of-earth.1045848/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Database of binary star data info within 10 PC of Earth</a> </h3> <div class="contentRow-snippet">I'm looking for a database of binary stars within 10 PC of Earth, including information such as eccentricity of orbits, their distance from one another, etc. I'm hoping to find a list with this information, or just a collection of pages with this information. I've tried Simbad but I can't find...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/sciencemaster.684428/" class="username " dir="auto" data-user-id="684428" data-xf-init="member-tooltip">Sciencemaster</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-09-24T17:53:01-0500" data-time="1664059981" data-date-string="Sep 24, 2022" data-time-string="5:53 PM" title="Sep 24, 2022 at 5:53 PM">Sep 24, 2022</time></li> <li> <dl class="tagList tagList--thread-1045848 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/binary/" data-xf-init="preview-tooltip" data-preview-url="/tags/binary/preview" class="tagItem tagItem--tag_binary" dir="auto"> Binary </a> <a href="/tags/binary-star/" data-xf-init="preview-tooltip" data-preview-url="/tags/binary-star/preview" class="tagItem tagItem--tag_binary-star" dir="auto"> Binary star </a> <a href="/tags/data/" data-xf-init="preview-tooltip" data-preview-url="/tags/data/preview" class="tagItem tagItem--tag_data" dir="auto"> Data </a> <a href="/tags/database/" data-xf-init="preview-tooltip" data-preview-url="/tags/database/preview" class="tagItem tagItem--tag_database" dir="auto"> Database </a> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/eccentricity/" data-xf-init="preview-tooltip" data-preview-url="/tags/eccentricity/preview" class="tagItem tagItem--tag_eccentricity" dir="auto"> Eccentricity </a> <a href="/tags/orbit/" data-xf-init="preview-tooltip" data-preview-url="/tags/orbit/preview" class="tagItem tagItem--tag_orbit" dir="auto"> Orbit </a> <a href="/tags/pc/" data-xf-init="preview-tooltip" data-preview-url="/tags/pc/preview" class="tagItem tagItem--tag_pc" dir="auto"> pc </a> <a href="/tags/star/" data-xf-init="preview-tooltip" data-preview-url="/tags/star/preview" class="tagItem tagItem--tag_star" dir="auto"> Star </a> <a href="/tags/stars/" data-xf-init="preview-tooltip" data-preview-url="/tags/stars/preview" class="tagItem tagItem--tag_stars" dir="auto"> Stars </a> </span> </dd> </dl> </li> <li>Replies: 5</li> <li>Forum: <a href="/forums/astronomy-and-astrophysics.71/">Astronomy and Astrophysics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="vcsharp2003"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/vcsharp2003.618199/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="618199" data-xf-init="member-tooltip" style="background-color: #3d0f3d; color: #cc33cc"> <span class="avatar-u618199-s" role="img" aria-label="vcsharp2003">V</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-does-the-electroscope-lose-electrons-to-the-earth.1045721/">How does the electroscope lose electrons to the Earth?</a> </h3> <div class="contentRow-snippet">I get step 1, in which due to electrostatic induction the top part of electroscope gets positively charged while the leaves of electroscope become negatively charged. Now if we Earth the positively charged end of electroscope as shown in step 2, then electrons must flow from Earth to...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/vcsharp2003.618199/" class="username " dir="auto" data-user-id="618199" data-xf-init="member-tooltip">vcsharp2003</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-09-20T02:59:32-0500" data-time="1663660772" data-date-string="Sep 20, 2022" data-time-string="2:59 AM" title="Sep 20, 2022 at 2:59 AM">Sep 20, 2022</time></li> <li> <dl class="tagList tagList--thread-1045721 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/earthing/" data-xf-init="preview-tooltip" data-preview-url="/tags/earthing/preview" class="tagItem tagItem--tag_earthing" dir="auto"> <em class="textHighlight">Earth</em>ing </a> <a href="/tags/electrons/" data-xf-init="preview-tooltip" data-preview-url="/tags/electrons/preview" class="tagItem tagItem--tag_electrons" dir="auto"> Electrons </a> <a href="/tags/electroscope/" data-xf-init="preview-tooltip" data-preview-url="/tags/electroscope/preview" class="tagItem tagItem--tag_electroscope" dir="auto"> Electroscope </a> <a href="/tags/electrostatic/" data-xf-init="preview-tooltip" data-preview-url="/tags/electrostatic/preview" class="tagItem tagItem--tag_electrostatic" dir="auto"> Electrostatic </a> <a href="/tags/electrostatic-induction/" data-xf-init="preview-tooltip" data-preview-url="/tags/electrostatic-induction/preview" class="tagItem tagItem--tag_electrostatic-induction" dir="auto"> Electrostatic induction </a> </span> </dd> </dl> </li> <li>Replies: 5</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="yohananregal"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/yohananregal.728636/" class="avatar avatar--s" data-user-id="728636" data-xf-init="member-tooltip"> <img src="/data/avatars/s/728/728636.jpg?1662670053" srcset="/data/avatars/m/728/728636.jpg?1662670053 2x" alt="yohananregal" class="avatar-u728636-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/hows-it-possible-that-70-of-earth-receives-sunlight-simultaneously.1045437/">How's it possible that 70% of Earth receives sunlight simultaneously</a> </h3> <div class="contentRow-snippet">How did you find PF?: Google Hello, I am new here. I am wondering, how is it possible for nearly 70% of the spherical Earth to be illuminated by the sun every July 8th? How can a sphere be illuminated beyond 50% with a single light source. How do we explain this?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/yohananregal.728636/" class="username " dir="auto" data-user-id="728636" data-xf-init="member-tooltip">yohananregal</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-09-08T15:43:42-0500" data-time="1662669822" data-date-string="Sep 8, 2022" data-time-string="3:43 PM" title="Sep 8, 2022 at 3:43 PM">Sep 8, 2022</time></li> <li> <dl class="tagList tagList--thread-1045437 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/sun/" data-xf-init="preview-tooltip" data-preview-url="/tags/sun/preview" class="tagItem tagItem--tag_sun" dir="auto"> Sun </a> <a href="/tags/sunlight/" data-xf-init="preview-tooltip" data-preview-url="/tags/sunlight/preview" class="tagItem tagItem--tag_sunlight" dir="auto"> Sunlight </a> </span> </dd> </dl> </li> <li>Replies: 37</li> <li>Forum: <a href="/forums/astronomy-and-astrophysics.71/">Astronomy and Astrophysics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Astronuc"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/astronuc.15685/" class="avatar avatar--s" data-user-id="15685" data-xf-init="member-tooltip"> <img src="/data/avatars/s/15/15685.jpg?1431188715" alt="Astronuc" class="avatar-u15685-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/measuring-earth-and-its-mountains.1016746/">Measuring Earth and its Mountains</a> </h3> <div class="contentRow-snippet">Earlier this year PBS NOVA broadcast a documentary on measuring mountains. It covered Everest (Nepali: सगरमाथा, romanized: Sagarmāthā; Tibetan: Chomolungma ཇོ་མོ་གླང་མ) and K2. The history behind measuring mountains and the elevations of Earth's surface is fascinating. The old way involved...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/astronuc.15685/" class="username " dir="auto" data-user-id="15685" data-xf-init="member-tooltip">Astronuc</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-07-10T22:17:34-0500" data-time="1657509454" data-date-string="Jul 10, 2022" data-time-string="10:17 PM" title="Jul 10, 2022 at 10:17 PM">Jul 10, 2022</time></li> <li> <dl class="tagList tagList--thread-1016746 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/measuring/" data-xf-init="preview-tooltip" data-preview-url="/tags/measuring/preview" class="tagItem tagItem--tag_measuring" dir="auto"> Measuring </a> </span> </dd> </dl> </li> <li>Replies: 6</li> <li>Forum: <a href="/forums/earth-sciences.84/">Earth Sciences</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Graham87"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/graham87.702025/" class="avatar avatar--s" data-user-id="702025" data-xf-init="member-tooltip"> <img src="/data/avatars/s/702/702025.jpg?1654698159" srcset="/data/avatars/m/702/702025.jpg?1654698159 2x" alt="Graham87" class="avatar-u702025-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/orbit-of-the-earth-numerical-methods-leapfrog.1016671/"><span class="prefix grass" dir="auto">Comp Sci</span><span class="label-append"> </span>Orbit of the Earth - numerical methods leapfrog</a> </h3> <div class="contentRow-snippet">I am attempting this homework exercise part b). I've modified my code but I get error overflow message. My goal is to modify my code so it returns kinetic and potential energy of Earth's orbit. I made a new f(z,t) and modified the rows 99 and 100 with dz[2]=-G*M*m/r, and dz[3]=0.5*m*y**2 but...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/graham87.702025/" class="username " dir="auto" data-user-id="702025" data-xf-init="member-tooltip">Graham87</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-07-07T06:36:55-0500" data-time="1657193815" data-date-string="Jul 7, 2022" data-time-string="6:36 AM" title="Jul 7, 2022 at 6:36 AM">Jul 7, 2022</time></li> <li> <dl class="tagList tagList--thread-1016671 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/numerical/" data-xf-init="preview-tooltip" data-preview-url="/tags/numerical/preview" class="tagItem tagItem--tag_numerical" dir="auto"> Numerical </a> <a href="/tags/numerical-methods/" data-xf-init="preview-tooltip" data-preview-url="/tags/numerical-methods/preview" class="tagItem tagItem--tag_numerical-methods" dir="auto"> Numerical methods </a> <a href="/tags/orbit/" data-xf-init="preview-tooltip" data-preview-url="/tags/orbit/preview" class="tagItem tagItem--tag_orbit" dir="auto"> Orbit </a> <a href="/tags/python/" data-xf-init="preview-tooltip" data-preview-url="/tags/python/preview" class="tagItem tagItem--tag_python" dir="auto"> Python </a> </span> </dd> </dl> </li> <li>Replies: 3</li> <li>Forum: <a href="/forums/engineering-and-comp-sci-homework-help.158/">Engineering and Comp Sci Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Graham87"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/graham87.702025/" class="avatar avatar--s" data-user-id="702025" data-xf-init="member-tooltip"> <img src="/data/avatars/s/702/702025.jpg?1654698159" srcset="/data/avatars/m/702/702025.jpg?1654698159 2x" alt="Graham87" class="avatar-u702025-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/orbit-of-earth-plotting-trajectory.1016646/"><span class="prefix grass" dir="auto">Comp Sci</span><span class="label-append"> </span>Orbit of Earth: Plotting Trajectory</a> </h3> <div class="contentRow-snippet">I am attempting this homework exercise but my plot does not show the whole trajectory. I don't know if it is something wrong with my equations or if it is a plotting matter. Cheers!This is my code:import matplotlib.pyplot as plt import numpy as np import scipy.integrate as spi G =...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/graham87.702025/" class="username " dir="auto" data-user-id="702025" data-xf-init="member-tooltip">Graham87</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2022-07-06T06:25:49-0500" data-time="1657106749" data-date-string="Jul 6, 2022" data-time-string="6:25 AM" title="Jul 6, 2022 at 6:25 AM">Jul 6, 2022</time></li> <li> <dl class="tagList tagList--thread-1016646 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> <em class="textHighlight">Earth</em> </a> <a href="/tags/numerical-methods/" data-xf-init="preview-tooltip" data-preview-url="/tags/numerical-methods/preview" class="tagItem tagItem--tag_numerical-methods" dir="auto"> Numerical methods </a> <a href="/tags/orbit/" data-xf-init="preview-tooltip" data-preview-url="/tags/orbit/preview" class="tagItem tagItem--tag_orbit" dir="auto"> Orbit </a> <a href="/tags/python/" data-xf-init="preview-tooltip" data-preview-url="/tags/python/preview" class="tagItem tagItem--tag_python" dir="auto"> Python </a> </span> </dd> </dl> </li> <li>Replies: 6</li> <li>Forum: <a href="/forums/engineering-and-comp-sci-homework-help.158/">Engineering and Comp Sci Homework Help</a></li> </ul> </div> </div> </div> </li> </ol> </div> <div class="block-outer block-outer--after"> <div class="block-outer-main"> <nav class="pageNavWrapper pageNavWrapper--logarithmic pageNavWrapper--full " data-block-size="3" data-last-page="20"> <div class="pageNav"> <ul class="pageNav-main"> <li class="pageNav-page 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