{"id":2987,"date":"2010-10-14T07:01:49","date_gmt":"2010-10-14T14:01:49","guid":{"rendered":"http:\/\/www.todayifoundout.com\/?p=2987"},"modified":"2013-08-02T23:00:49","modified_gmt":"2013-08-03T06:00:49","slug":"why-the-hottest-part-of-the-summer-is-called-the-dog-days","status":"publish","type":"post","link":"http:\/\/www.todayifoundout.com\/index.php\/2010\/10\/why-the-hottest-part-of-the-summer-is-called-the-dog-days\/","title":{"rendered":"Why the Hottest Part of the Summer is Called the \u201cDog Days\u201d"},"content":{"rendered":"<div class=\"pf-content\"><p><a href=\"http:\/\/www.todayifoundout.com\/wp-content\/uploads\/2010\/10\/Sirius.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-2999\" title=\"Sirius\" alt=\"Sirius\" src=\"http:\/\/www.todayifoundout.com\/wp-content\/uploads\/2010\/10\/Sirius-e1287059120229.jpg\" width=\"340\" height=\"246\" \/><\/a><a href='http:\/\/www.todayifoundout.com' title='Interesting Facts'>Today I found out<\/a> why the hottest part of the summer is called the &#8220;Dog Days&#8221;.<\/p>\n<p>The earliest reference to some aspect of this expression goes all the way back to the Ancient Egyptians.\u00a0 They noted that the heliacal rising of the star Sirius heralded the hottest part of the summer.\u00a0 However, it isn&#8217;t exactly known why the ancient Egyptians associated this star with a dog (the star&#8217;s hieroglyph is a dog).\u00a0 Sirius would appear in Egypt, after about a 70 day absence, just before the season where the Nile typically floods.\u00a0 So it is thought the star&#8217;s hieroglyphic symbol being a dog symbolized a &#8220;watchdog&#8221;.<\/p>\n<p>On the other hand, it&#8217;s very possible it was for the same reason the Ancient Greeks and Ancient Romans would also eventually associate this star with a dog.\u00a0 Namely, that it is the brightest star in what is now known as the Canis Major (Latin for &#8220;Greater Dog&#8221; or &#8220;Big Dog&#8221;) constellation.\u00a0 This constellation simply looks a little bit like a dog and Sirius is the brightest star in the constellation, so the star got named the &#8220;Dog Star&#8221; and it&#8217;s heliacal rising marked the start of the hottest part of the year, which then became the &#8220;Dog Days&#8221;.<\/p>\n<p>The Roman&#8217;s expression for Dog Days was di\u0113s canicul\u0101r\u0113s (Latin for &#8220;Dog Days&#8221;).\u00a0 The Greeks also had a similar expression that literally translated to &#8220;Dog Days&#8221;.\u00a0 They both believed that, when Sirius rose around the same time as the Sun, this contributed to that time of year becoming hotter.\u00a0 As such, they would often make sacrifices to Sirius, including sacrificing dogs, to appease Sirius with the hope that this would result in a mild summer and would protect their crops from scorching.<\/p>\n<p>If you liked this article, you might also enjoy our new popular podcast, The BrainFood Show (<a href=\"https:\/\/itunes.apple.com\/us\/podcast\/the-brainfoodshow\/id1350586459\" rel=\"nofollow\" target=\"_blank\">iTunes<\/a>, <a href=\"https:\/\/open.spotify.com\/show\/36xpXQMPVXhWJzMoCHPJKd\" target=\"_blank\">Spotify<\/a>, <a href=\"https:\/\/playmusic.app.goo.gl\/?ibi=com.google.PlayMusic&#038;isi=691797987&#038;ius=googleplaymusic&#038;apn=com.google.android.music&#038;link=https:\/\/play.google.com\/music\/m\/Insimdi4g6puyyr4qbt6tup5b6m?t%3DThe_BrainFood_Show%26pcampaignid%3DMKT-na-all-co-pr-mu-pod-16\" rel=\"nofollow\" target=\"_blank\">Google Play Music<\/a>, <a href=\"http:\/\/www.todayifoundout.com\/index.php\/feed\/brainfood\/\" target=\"_blank\">Feed<\/a>), as well as:<\/p>\n<ul>\n<li><a href=\"http:\/\/www.todayifoundout.com\/index.php\/2013\/02\/why-we-call-the-seasons-summer-autumn-winter-and-spring\/\" target=\"_blank\">Why We Call the Seasons Summer, Autumn, Winter, and Spring<\/a><\/li>\n<li><a href=\"http:\/\/www.todayifoundout.com\/index.php\/2012\/12\/why-do-people-seem-to-get-more-colds-in-the-winter\/\" target=\"_blank\">Why People Seem to Get More Colds in the Winter<\/a><\/li>\n<li><a href=\"http:\/\/www.todayifoundout.com\/index.php\/2012\/06\/what-causes-dew\/\" target=\"_blank\">What Causes Dew<\/a><\/li>\n<li><a href=\"http:\/\/www.todayifoundout.com\/index.php\/2013\/05\/1816-the-year-that-had-no-summer\/\" target=\"_blank\">The Year That Had No Summer<\/a><\/li>\n<li><a href=\"http:\/\/www.todayifoundout.com\/index.php\/2011\/09\/why-leaves-change-color-in-the-fall\/\" target=\"_blank\">Why Leaves Change Color in the Fall<\/a><\/li>\n<\/ul>\n<p><span id=\"bonusfacts\">Bonus<\/span> Facts:<\/p>\n<ul>\n<li>Canis Major is listed in Ptolemy&#8217;s 48 constellations all the way back in the 2nd century.\u00a0\u00a0 The name Sirius itself means &#8220;scorching star&#8221; or &#8220;scorcher&#8221; and comes from the Ancient Greek \u03a3\u03b5\u03af\u03c1\u03b9\u03bf\u03c2 Seirios.<\/li>\n<li>Sirius-A is the brightest star visible to the naked eye from Earth, being almost twice as bright as Canopus.\u00a0 Sirius-A and Sirius-B combine to form a binary system and appear as one star to the naked eye, though the vast majority of luminosity to the naked eye comes from Sirius-A, Sirius-B being a white dwarf which is only around 30 AU (astronomical units) away from Sirius-A.\u00a0 It is also theorized that there is a Sirius-C; but to date, this has not been proven.\u00a0 Sirius A and B (and possibly C) combine to form a bright point known as Sirius.<\/li>\n<li>For those who don&#8217;t know, one astronomical unit is the average distance between the Earth and the Sun.\u00a0 A white dwarf is a former star that is nearing the end of its life-cycle, with no further nuclear fusion going on at its core.\u00a0 Once most stars have used up the fuel at their core, they go into a red-giant or red super-giant phase and expand to incredible sizes.\u00a0 At the end of this phase, when the star has used up all its fuel that it can use via nuclear fusion, if it has enough mass, it will extremely rapidly collapse and create one of the most powerful explosions in the universe, the supernova.\u00a0 The burst of energy from a single supernova can briefly out-shine an entirely galaxy full of billions of stars.\u00a0 If the red giant doesn&#8217;t have enough mass, it will simply collapse into a white dwarf and spend a couple billion years slowly dimming as it gives off its stored energy.<\/li>\n<li>Some star remnants are too small to begin with and so don&#8217;t ever go into a red giant phase.\u00a0 When they do go into their &#8220;red&#8221; phase, they are called &#8220;red dwarfs&#8221;.\u00a0 However, the lifespan of these stars is longer than the universe has existed.\u00a0 Thus, every star that will eventually become a red dwarf is still around today and has not reached the red dwarf phase.\u00a0 As a general rule with stars, the bigger and brighter it is, the faster it burns out.\u00a0 The smaller it is, the longer it lives.<\/li>\n<li>Our Sun will eventually become a red giant (and would engulf the Earth, if the Earth was still at its present orbit 5 billion years from now or so when that will happen).\u00a0 Once the red giant phase is over, it will then contract into a white dwarf as it doesn&#8217;t have enough mass to go supernova.<\/li>\n<li>Even though our sun may not engulf the Earth, due to the Earth&#8217;s orbit increasing, because of the increased energy coming from the sun as it expands, in about 3 billion years, all water will be burned off the Earth.\u00a0 So sometime between now and 3 billion years from now, we need to find another home or figure out how to move the entire Earth.<\/li>\n<li>For reference to the amazing scale of our Sun&#8217;s size now vs. as a red giant vs. as a white dwarf, our Sun could hold about 1.3 million Earths right now at its present size.\u00a0 When it reaches the peak of its red giant phase, it will expand to about 1.3 AU, meaning it could hold about 28 trillion Earths.\u00a0 Once it contracts down to a white dwarf, it will be about the same size as Earth.<\/li>\n<li>Sirius-A is a white main sequence star (A1V) that is about twice the size of our Sun.\u00a0 This isn&#8217;t very massive, relatively speaking.\u00a0 The extreme brightness from our point of view then comes not so much because it is a particularly bright star, but rather because it is only 8.6 light years away (2.6 parsecs).\u00a0 That&#8217;s a really long ways away by standards of distance we normally deal with, but by galactic standards, that&#8217;s just next door and, indeed, it is one of our nearest neighbors.<\/li>\n<li>The French term &#8220;canicule&#8221; meaning &#8220;little dog&#8221; is used to refer to heat waves and this period of the summer known as &#8220;dog days&#8221; in English.<\/li>\n<li>In Ancient Rome, the Dog Days went from July 24th through August 24.\u00a0 According to the old Farmer&#8217;s Almanac, the Dog Days go from July 3rd to August 11th.\u00a0 It is during this period that rainfall is at its lowest in the Northern Hemisphere.<\/li>\n<li>The Egyptians also based their calendar on the heliacal rising of Sirius when it would first become visible before sunrise after a 70 day absence from the skies.<\/li>\n<li>People from the Greek island of Ceos in the Aegean Sea offered regular sacrifices to Sirius and Zeus in hopes that this would bring about cooling breezes during the Dog Days.\u00a0 When the star would first rise, if it would rise looking misty or faint, they would expect pestilence to follow.\u00a0 If it arose clear, they would expect good fortune that year.<\/li>\n<li>The Ancient Romans also sacrificed a dog upon the setting of Sirius around April 25th.\u00a0 They sacrificed this dog along with other animals, to the goddess Robigo, in the hopes of having good wheat crops in the coming summer.<\/li>\n<li>A feast day is celebrated on August 16th, in honor of Saint Roch, the patron saint of dogs.<\/li>\n<li>Sirius Black, in Harry Potter, is thought to have been named after the white dwarf, Sirius B.\u00a0 The relationship is further extended by the fact the character Sirius Black was an animagus that could change into a dog.<\/li>\n<li>The dog days are mentioned in Dickens&#8217; A Christmas Carol (passage referring to Scrooge): &#8220;A frosty rime was on his head, and on his eyebrows, and his wiry chin. He carried his own low temperature always about with him; he iced his office in the dogdays; and didn&#8217;t thaw it one degree at Christmas.&#8221;<\/li>\n<li>It is also mentioned in Homer&#8217;s <em>Iliad<\/em>:\u00a0 Sirius rises late in the dark, liquid sky.\u00a0 On summer nights, star of stars, Orion&#8217;s Dog they call it, brightest Of all, but an evil portent, bringing heat And fevers to suffering humanity.<\/li>\n<\/ul>\n<span class=\"collapseomatic \" id=\"id69e146ab45d5c\"  tabindex=\"0\" title=\"Expand for References:\"    >Expand for References:<\/span><div id=\"target-id69e146ab45d5c\" class=\"collapseomatic_content \">\n<ul>\n<li><a title=\"Etymology of Dog Days\" href=\"http:\/\/www.etymonline.com\/index.php?term=dog+days\" target=\"_blank\">Etymology: Dog Days<\/a><\/li>\n<li><a title=\"Dog Days\" href=\"http:\/\/en.wikipedia.org\/wiki\/Dog_Days\" target=\"_blank\">Dog Days<\/a><\/li>\n<li><a title=\"Canicule\" href=\"http:\/\/www.thefreedictionary.com\/Canicule\" target=\"_blank\">Canicule<\/a><\/li>\n<li><a title=\"Sirius\" href=\"http:\/\/en.wikipedia.org\/wiki\/Sirius\" target=\"_blank\">Sirius<\/a><\/li>\n<li><a title=\"Canis Major\" href=\"http:\/\/en.wikipedia.org\/wiki\/Canis_Major\" target=\"_blank\">Canis Major<\/a><\/li>\n<li><a title=\"A Christmas Carol\" href=\"http:\/\/www.amazon.com\/gp\/product\/0517229277?ie=UTF8&amp;tag=vicastingcom-20&amp;linkCode=as2&amp;camp=1789&amp;creative=390957&amp;creativeASIN=0517229277\" target=\"_blank\">A Christmas Carol<\/a><\/li>\n<li><a title=\"The Iliad\" href=\"http:\/\/www.amazon.com\/gp\/product\/1435110439?ie=UTF8&amp;tag=vicastingcom-20&amp;linkCode=as2&amp;camp=1789&amp;creative=390957&amp;creativeASIN=1435110439\" target=\"_blank\">The Iliad<\/a><\/li>\n<li><a title=\"Distant Future of the Sun and Earth Revisited\" href=\"http:\/\/arxiv.org\/abs\/0801.4031\" target=\"_blank\">Distant Future of the Sun and Earth Revisited<\/a><\/li>\n<li><a title=\"Red Giant\" href=\"http:\/\/en.wikipedia.org\/wiki\/Red_giant\" target=\"_blank\">Red Giant<\/a><\/li>\n<li><a title=\"White Dwarf\" href=\"http:\/\/en.wikipedia.org\/wiki\/White_dwarf\" target=\"_blank\">White Dwarf<\/a><\/li>\n<li><a title=\"Earth and Sun Size\" href=\"http:\/\/imagine.gsfc.nasa.gov\/docs\/ask_astro\/answers\/970518a.html\" target=\"_blank\">Earth and Sun Size<\/a><\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p><a href='http:\/\/www.todayifoundout.com' title='Interesting Facts'>Today I found out<\/a> why the hottest part of the summer is called the &#8220;Dog Days&#8221;. The earliest reference to some aspect of this expression goes all the way back to the Ancient Egyptians.\u00a0 They noted that the heliacal rising of the star Sirius heralded the hottest part of the summer.\u00a0 However, it isn&#8217;t exactly known why the ancient Egyptians [&#8230;]<\/p>\n","protected":false},"author":2,"featured_media":2999,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,7],"tags":[328,137,221,131,615],"class_list":["post-2987","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-today-i-found-out","category-language","tag-astronomy","tag-etymology","tag-history-2","tag-language-2","tag-summer"],"_links":{"self":[{"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/posts\/2987","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/comments?post=2987"}],"version-history":[{"count":11,"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/posts\/2987\/revisions"}],"predecessor-version":[{"id":2998,"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/posts\/2987\/revisions\/2998"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/media\/2999"}],"wp:attachment":[{"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/media?parent=2987"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/categories?post=2987"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.todayifoundout.com\/index.php\/wp-json\/wp\/v2\/tags?post=2987"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}