Vísindavefurinn

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class="cat-teal"> <a href="/vegna_thess.php?id=43"> <img src="/design/i_vv/icon-neurology.svg" alt=""> <span style="color:#00457C"> Vísindavefur </span> <img class="arrow-icon" src="/design/i_vv/arrow_right.svg"> </a> </li> <li class="cat-teal"> <a href="/vegna_thess.php?id=202"> <img src="/design/i_vv/icon-account-balance.svg" alt=""> <span style="color:#00457C"> Þverfræðilegt efni </span> <img class="arrow-icon" src="/design/i_vv/arrow_right.svg"> </a> </li> </ul> </nav> <div class="header-desktop"> <nav class="desktop-nav" role="navigation"> <ul> <li><a href="/svar.php?id=73555">Tölfræði</a></li> <li><a href="/svar.php?id=70789">Um vefinn</a></li> <li><a href="/svar.php?id=70790">Þjónusta</a></li> <li class="search"> <form class="searchbar" action="/search/" method="GET"> <input type="search" name="q" class="d-search" placeholder="Sláðu inn leitarorð og ýttu á „enter“" /> <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none"> <mask 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class="data-item"> <img src="/design/i_vv/icon-flood.svg" alt="Flóð"> Flóð <strong>Árdegis: 07:09 • Síðdegis: 19:28</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-tide.svg" alt="Fjaran"> Fjara <strong>Árdegis: 01:05 • Síðdegis: 13:22</strong> <span>í Reykjavík</span> </div> </div> </div> </div> <div class="header-data"> <div class="data-item"> <img src="/design/i_vv/icon-sun.svg" alt="Sólin"> Sólin <strong>Rís 07:45 • sest 19:29</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-moon.svg" alt="Tunglið"> Tunglið <strong>Rís 21:35 • Sest 07:49</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-flood.svg" alt="Flóð"> Flóð <strong>Árdegis: 07:09 • Síðdegis: 19:28</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-tide.svg" alt="Fjaran"> Fjara <strong>Árdegis: 01:05 • Síðdegis: 13:22</strong> <span>í Reykjavík</span> </div> </div> </header> <div class="poppin md-send"> <a class="instructions" href="#">Leiðbeiningar<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-help-circle"><circle cx="12" cy="12" r="10"></circle><path d="M9.09 9a3 3 0 0 1 5.83 1c0 2-3 3-3 3"></path><line x1="12" y1="17" x2="12.01" y2="17"></line></svg></a><a class="instructions-close" href="#">Til baka <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-arrow-left"><line x1="19" y1="12" x2="5" y2="12"></line><polyline points="12 19 5 12 12 5"></polyline></svg></a> <h2>Sendu inn spurningu </h2> <div class="instructions-more"> <p class="first">Hér getur þú sent okkur nýjar spurningar um vísindaleg efni.</p> <p>Hafðu spurninguna stutta og hnitmiðaða og sendu aðeins eina í einu. Einlægar og vandaðar spurningar um mikilvæg efni eru líklegastar til að kalla fram vönduð og greið svör. Ekki er víst að tími vinnist til að svara öllum spurningum.</p> <p>Persónulegar upplýsingar um spyrjendur eru eingöngu notaðar í starfsemi vefsins, til dæmis til að svör verði við hæfi spyrjenda. Spurningum er ekki sinnt ef spyrjandi villir á sér heimildir eða segir ekki nægileg deili á sér.</p> <p>Spurningum sem eru ekki á verksviði vefsins er eytt.</p> <p>Að öðru leyti er hægt að spyrja Vísindavefinn um allt milli himins og jarðar!</p> <div class="content-left-sep"></div> </div> <form action="/hvers_vegna.php?id=" method="POST" name="question_send"> <div class="md-fields"> <input type="hidden" name="step" value="4"> <div class="md-input"> <label for="s-fname">Nafn</label> <input type="text" name="f_name" class="send-input" id="s-fname" required="required" value=""> <input type="hidden" name="l_name" class="send-input" id="s-sname" value=""> </div> <div class="md-input"> <label for="s-email">Netfang</label> <input type="email" name="email" class="send-input" id="s-email" required="required" value=""> </div> <div class="md-input"> <label for="s-byear">Fæðingarár</label> <input type="number" name="birthyear" class="send-input" id="s-byear" maxlength="4" required="required" value=""> </div> <div class="md-input"> <label for="s-math">Ruslpóstvörn</label> <input type="hidden" name="vv_math_problem_hash_id" class="vv_math_problem_hash_id" id="vv_math_problem_hash_id" value=""> <input type="text" name="vv_math_problem_answer" id="vv_math_problem_answer" class="send-input" valuesize="2" maxlength="2" required="required" style="width: 30%;"> <span class="s-math-container"> = <span class="math_problem_num1_txt"></span> <img class="math_problem_math_icon" src="" /> <span class="math_problem_num2_txt"></span> </span> </div> <div class="md-input"> <label for="s-question">Spurning</label> <textarea type="text" name="question" class="send-input i-question" id="s-question" rows="6" required="required"></textarea> </div> </div> <div class="md-actions"> <button type="button" value="" class="btn btn-white"><i data-feather="x"></i> Hætta við</button> <button type="submit" value="Senda" class="btn send-button"><i data-feather="check"></i> Senda</button> </div> </form> </div> <section class="layout"> <div class="main-content"> <section class="layout-item"> <div class="article-wrapper"> <article class="default-article"> <div class="article-header"> <h1> <a href="/svar.php?id=86451" > Lifir einhver dýrategund á Íslandi sem finnst hvergi annars staðar? </a> </h1> </div> <div class="article-meta"> <div class="publish-date" style="display: block;"> <h4>Útgáfudagur:</h4> <p>14.03.2025</p> </div> <div class="publisher" style="display: none;"> <h4>Spyrjandi:</h4> <p>Örn </p> </div> <div class="author"> <h4>Höfundur:</h4> <p>Jón Már Halldórsson</p> </div> </div> <div class="article-text"> <p> Upprunalega spurningin hljóðaði svona: Er hægt að tiltaka einhverja dýrategund sem séríslenska? Í þessu svari er gengið út frá því átt sé við tegundir sem eru einlendar (e. endemic) hér á landi. Í líffræði er talað um að tegund lífveru sé einl ... </p> <a href="/svar.php?id=86451" class="btn btn-brand">Sjá nánar <svg width="24" height="24" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg"> <g id="Icon"> <path id="arrow_forward" d="M12 20L10.575 18.6L16.175 13H4V11H16.175L10.575 5.4L12 4L20 12L12 20Z" fill="#1C1C1C"/> </g> </svg> </a> </div> </article> <div class="article-hero"> <a href="/svar.php?id=86451"> <img src="/myndir/thumbs/crymostygius_thingvallensis2_100325_thumb_600w.jpg" alt="Lifir einhver dýrategund á Íslandi sem finnst hvergi annars staðar?" /> </a> </div> </div> </section>  <section class="layout-item"> <div class="sp-top-img" style="text-align: center;" > <a href="http://www.hhi.is" target="_blank"><img src="/auglysingar/hhi_visindavefur_2025.gif" alt="HHÍ - febrúar 2025 auglýsing" /></a> </div> </section>  <section class="backdrop-blue"> <div class="recent-answers layout-item"> <h2 class="section-title">Nýjustu svörin</h2> <a class="arrow-btn" href="/vegna_thess.php?id=138">Skoða öll nýjustu svörin <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-arrow-right"><line x1="5" y1="12" x2="19" y2="12"></line><polyline points="12 5 19 12 12 19"></polyline></svg></a></h2> <div class="recent-answers-wrapper"> <article class="recent-article"> <a href="/svar.php?id=87643" class="recent-article-wrapper"> <div class="recent-category" style="border-color: #c0a14b" > Sagnfræði: Íslandssaga </div> <h4>Hefur íslenskt samfélag einhvern tíma verið stéttlaust?</h4> </a> </article> <article class="recent-article"> <a href="/svar.php?id=87598" class="recent-article-wrapper"> <div class="recent-category" style="border-color: #EB7125" > Stærðfræði </div> <h4>Er stærðfræði tungumál? </h4> </a> </article> <article class="recent-article"> <a href="/svar.php?id=86880" class="recent-article-wrapper"> <div class="recent-category" style="border-color: #c0a14b" > Málvísindi: íslensk </div> <h4>Hvað merkir orðið „blá“ í samhenginu „mýrar og blár“ og „engjar og blár“?</h4> </a> </article> </div> </div> </section> <section class="layout-item"> <div class="science-calendar"> <h2 class="section-title">Vísindadagatal 15. mars</h2> <div class=""> <a class="science-calendar-wrapper" id="science-calendar-story" > <div class="science-item-hero"> <img src="/myndir/sciday_uhlenbeck.jpg" alt="Karen Uhlenbeck"> </div> <div class="science-item-content"> <p class="section-title">Vísindasagan</p> <h1>Karen Uhlenbeck</h1> <h2>1942</h2> <p>Bandarískur stærðfræðingur, hefur m.a. unnið að rannsóknum á hlutafleiðujöfnum, hnikareikningi, kvarðafræði, ólínulegum bylgjum og Schrödinger-jöfnum.</p> </div> </a> <a href="/svar.php?id=19920" class="science-calendar-wrapper" id="science-calendar-informed" > <div class="science-item-hero"> <img src="/myndir/sciday_2016_74.jpg" alt=" Steinöld"> </div> <div class="science-item-content"> <p class="section-title">Dagatal hinna upplýstu</p> <h1> Steinöld</h1> <h2></h2> <p>Hugtakið steinöld kemur frá danska fornleifafræðingnum Christian Jürgensen Thomsen (1788–1865) sem setti fram svonefnda þriggja alda kenningu þar sem forsögu Norðurlanda var skipt í þrjár aldir: steinöld, bronsöld og járnöld. Steinöld hófst fyrir rúmum 2 milljónum ára og er skipt í þrjú tímabil. Okkar tegund manna kom fram á síðari hluta fornsteinaldar, föst búseta kemur fram á miðsteinöld en landbúnaður þróaðist á nýsteinöld.</p> <div class="btn">Nánar <svg width="24" height="24" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg"><g id="Icon"><path id="arrow_forward" d="M12 20L10.575 18.6L16.175 13H4V11H16.175L10.575 5.4L12 4L20 12L12 20Z" fill="#1C1C1C"></path></g></svg> </div> </div> </a> <a href="/svar.php?id=75482" class="science-calendar-wrapper" id="science-calendar-icelandic" > <div class="science-item-hero"> <img src="/myndir/kristin_briem_dagatal_smamynd_140318.jpg" alt="Kristín Briem"> </div> <div class="science-item-content"> <p class="section-title">Íslenskir vísindamenn</p> <h1>Kristín Briem</h1> <h2>1964</h2> <p>Kristín Briem er prófessor við námsbraut í sjúkraþjálfun á Heilbrigðisvísindasviði Háskóla Íslands. Rannsóknasvið hennar tengist hreyfivísindum og þá sérstaklega hlutlægri greiningu á hreyfingu og athafnagetu mannsins.</p> <div class="btn">Nánar <svg width="24" height="24" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg"><g id="Icon"><path id="arrow_forward" d="M12 20L10.575 18.6L16.175 13H4V11H16.175L10.575 5.4L12 4L20 12L12 20Z" fill="#1C1C1C"></path></g></svg> </div> </div> </a> </div> </div> </section> <section class="backdrop-blue"> <div class="recent-answers tab-answers layout-item">  <h2 class="section-title">Vinsæl svör <div class="tab-nav"> <a href="#vinsaelsvor-day" class="--active" > Í dag </a> <a href="#vinsaelsvor-week" > Í vikunni  </a> </div> </h2> <div class="tabs"> <div class="recent-answers-wrapper tab --active" id="vinsaelsvor-day"> <article class="recent-article"> <a href="/svar.php?id=84708" class="recent-article-wrapper"> <div class="recent-category" style="border-color: #c0a14b" > Sagnfræði: mannkynssaga </div> <h4>Hverjar eru ástæður 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