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Vísindavefurinn
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src="/design/i_vv/icon-category.svg" alt=""> <span>Allir flokkar</span> <img class="arrow-icon" src="/design/i_vv/arrow_right.svg"> </a> </li> <li class="cat-teal"> <a href="/vegna_thess.php?id=3"> <img src="/design/i_vv/icon-diversity.svg" alt=""> <span style="color:#719500"> Félagsvísindi </span> <img class="arrow-icon" src="/design/i_vv/arrow_right.svg"> </a> </li> <li class="cat-teal"> <a href="/vegna_thess.php?id=11"> <img src="/design/i_vv/icon-spa.svg" alt=""> <span style="color:#0098AA"> Heilbrigðisvísindi </span> <img class="arrow-icon" src="/design/i_vv/arrow_right.svg"> </a> </li> <li class="cat-teal"> <a href="/vegna_thess.php?id=2"> <img src="/design/i_vv/icon-neurology.svg" alt=""> <span style="color:#c0a14b"> Hugvísindi </span> <img class="arrow-icon" src="/design/i_vv/arrow_right.svg"> </a> </li> <li class="cat-teal"> <a href="/vegna_thess.php?id=152"> <img src="/design/i_vv/icon-school.svg" alt=""> <span style="color:#AC1A2F"> Menntavísindi </span> <img 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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 id="mask0_853_7542" style="mask-type:alpha" maskUnits="userSpaceOnUse" x="0" y="0" width="24" height="24"> <rect width="24" height="24" fill="#D9D9D9"/> </mask> <g mask="url(#mask0_853_7542)"> <path d="M19.6 21L13.3 14.7C12.8 15.1 12.225 15.4167 11.575 15.65C10.925 15.8833 10.2333 16 9.5 16C7.68333 16 6.146 15.371 4.888 14.113C3.62933 12.8543 3 11.3167 3 9.5C3 7.68333 3.62933 6.14567 4.888 4.887C6.146 3.629 7.68333 3 9.5 3C11.3167 3 12.8543 3.629 14.113 4.887C15.371 6.14567 16 7.68333 16 9.5C16 10.2333 15.8833 10.925 15.65 11.575C15.4167 12.225 15.1 12.8 14.7 13.3L21 19.6L19.6 21ZM9.5 14C10.75 14 11.8127 13.5627 12.688 12.688C13.5627 11.8127 14 10.75 14 9.5C14 8.25 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class="data-item"> <img src="/design/i_vv/icon-sun.svg" alt="Sólin"> Sólin <strong>Rís 06:23 • sest 20:38</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-moon.svg" alt="Tunglið"> Tunglið <strong>Rís 12:47 • Sest 06:50</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-flood.svg" alt="Flóð"> Flóð <strong>Árdegis: 02:27 • Síðdegis: 15:26</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-tide.svg" alt="Fjaran"> Fjara <strong>Árdegis: 09:09 • Síðdegis: 21:29</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 06:23 • sest 20:38</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-moon.svg" alt="Tunglið"> Tunglið <strong>Rís 12:47 • Sest 06:50</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-flood.svg" alt="Flóð"> Flóð <strong>Árdegis: 02:27 • Síðdegis: 15:26</strong> <span>í Reykjavík</span> </div> <div class="data-item"> <img src="/design/i_vv/icon-tide.svg" alt="Fjaran"> Fjara <strong>Árdegis: 09:09 • Síðdegis: 21:29</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=87630" > Er eitthvað til í því að reginrisinn Betelgás verði brátt sprengistjarna? </a> </h1> </div> <div class="article-meta"> <div class="publish-date" style="display: block;"> <h4>Útgáfudagur:</h4> <p>07.04.2025</p> </div> <div class="publisher" style="display: none;"> <h4>Spyrjandi:</h4> <p>María, Þorvaldur</p> </div> <div class="author"> <h4>Höfundur:</h4> <p>Gunnlaugur Björnsson</p> </div> </div> <div class="article-text"> <p> Sprengistjörnur blossa upp í vetrarbrautinni okkar að jafnaði á fimmtíu til hundrað ára fresti. Þær geta orðið svo bjartar að þær sjáist vel berum augum og jafnvel að degi til. Síðast sást svo björt sprengistjarna árið 1604 og er hún kennd við Jóhann ... </p> <a href="/svar.php?id=87630" 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=87630"> <img src="/myndir/thumbs/betelgas_reginrisi_190325_thumb_600w.jpg" alt="Er eitthvað til í því að reginrisinn Betelgás verði brátt sprengistjarna?" /> </a> </div> </div> </section> <!-- ads begin --> <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> <!-- ads end --> <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=87451" class="recent-article-wrapper"> <div class="recent-category" style="border-color: #EB7125" > Stærðfræði </div> <h4>Er ennþá verið að finna upp á nýjum formúlum og jöfnum í stærðfræði?</h4> </a> </article> <article class="recent-article"> <a href="/svar.php?id=87555" class="recent-article-wrapper"> <div class="recent-category" style="border-color: #c0a14b" > Málvísindi: íslensk </div> <h4>Hversu gamalt er orðið gerpla í málinu og hvað þýðir það? </h4> </a> </article> <article class="recent-article"> <a href="/svar.php?id=87458" class="recent-article-wrapper"> <div class="recent-category" style="border-color: #0098AA" > Læknisfræði </div> <h4>Er eitthvað vitað um langtímaafleiðingar rafrettureykinga?</h4> </a> </article> </div> </div> </section> <section class="layout-item"> <div class="science-calendar"> <h2 class="section-title">Vísindadagatal 7. apríl</h2> <div class=""> <a href="/svar.php?id=59052" class="science-calendar-wrapper" id="science-calendar-story" > <div class="science-item-hero"> <img src="/myndir/sciday_popper.jpg" alt="Karl R. Popper"> </div> <div class="science-item-content"> <p class="section-title">Vísindasagan</p> <h1>Karl R. Popper</h1> <h2>1902-1994</h2> <p>Austurrísk-breskur heimspekingur, m.a. þekktur fyrir rit um söguhyggju og opið samfélag, um aðferðir vísinda, afmörkun þeirra og hrekjanleika í vísindum.</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=70309" class="science-calendar-wrapper" id="science-calendar-informed" > <div class="science-item-hero"> <img src="/myndir/sciday_2016_97.jpg" alt=" Hirðfífl"> </div> <div class="science-item-content"> <p class="section-title">Dagatal hinna upplýstu</p> <h1> Hirðfífl</h1> <h2></h2> <p>Elstu þekktu heimildir um hirðfífl eru frá Fornegyptum. Þar gegndu dvergvaxnir blökkumenn hlutverki trúða. Efnaðir Rómverjar höfðu sumir trúða og við hirðir í Evrópu á miðöldum voru yfirleitt hirðfífl. Þau áttu að haga sér fíflalega eins og heimskingjar en gátu einnig sagt höfðingjum óbeint til syndanna eða leiðbeint þeim. Hirðfífl eru þekktar persónur í bókmenntum, t.d. í leikritum Shakespeares.</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=75615" class="science-calendar-wrapper" id="science-calendar-icelandic" > <div class="science-item-hero"> <img src="/myndir/pall_einarsson_050418.png" alt="Páll Einarsson"> </div> <div class="science-item-content"> <p class="section-title">Íslenskir vísindamenn</p> <h1>Páll Einarsson</h1> <h2>1947</h2> <p>Páll Einarsson er prófessor emeritus við jarðvísindadeild Háskóla Íslands og hefur rannsóknaraðstöðu við Jarðvísindastofnun Háskólans. 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