{"id":2832,"date":"2015-02-22T11:09:21","date_gmt":"2015-02-22T11:09:21","guid":{"rendered":"http:\/\/revoscience.com\/en\/?p=2832"},"modified":"2015-02-22T11:09:21","modified_gmt":"2015-02-22T11:09:21","slug":"venus-the-brightest-planet","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/venus-the-brightest-planet\/","title":{"rendered":"Venus: The brightest planet"},"content":{"rendered":"
\"Venus<\/a>
Venus and the moon by EarthSky<\/figcaption><\/figure>\n

Venus is\u00a0<\/span>much\u00a0brighter than any other planet viewed in Earth\u2019s sky. It\u2019s the third-brightest object in the sky, after the sun and moon.<\/span><\/span><\/p>\n

Why is Venus so bright?\u00a0<\/strong><\/span><\/p>\n

As the planet next-inward from Earth in orbit around the sun, Venus is relatively nearby. But it\u2019s nearness isn’t the only reason Venus is bright. Consider that Mars orbits one step outward from Earth. And Mars waxes and wanes in brightness in our sky. It\u2019s only exceptionally bright around the time Earth passes between Mars and the sun, when the Red Planet is at its closest to us.<\/span><\/p>\n

With Venus, something else is going on. Astronomers use the term\u00a0albedo\u00a0to describe how bright a planet is in absolute terms. When sunlight strikes a planet, some of the light is absorbed by the planet\u2019s surface or atmosphere \u2013 and some is reflected. Albedo is a comparison between how much light strikes an object \u2013 and how much is reflected.<\/span><\/p>\n

Venus has the highest albedo of any major planet in our solar system. Its albedo is close to .7, meaning it reflects about 70 percent of the sunlight striking it. When the moon is close to full in Earth\u2019s sky, it can look a lot brighter than Venus, but the moon reflects only about 10 percent of the light that hits it. The moon\u2019s low albedo is due to the fact that our companion world is made of dark volcanic rock. It appears bright to us only because of its nearness to Earth. It\u2019s only about a light-second away, in contrast for several light-minutes for Venus.<\/span><\/p>\n

Venus is so bright (it has a high albedo) because it\u2019s blanketed by highly reflective clouds. The clouds in the atmosphere of Venus contain droplets of sulfuric acid, as well as acidic crystals suspended in a mixture of gases. Light bounces easily off the smooth surfaces of these spheres and crystals. Sunlight bouncing from these clouds is a big part of the reason that Venus is so bright.<\/span><\/p>\n

By the way, Venus isn\u2019t the most reflective body in our solar system. That honor goes to Enceladus, a moon of Saturn. Its icy surface reflects some 90% of the sunlight striking it.<\/span><\/p>\n

When will Venus be at its brightest for 2015?<\/strong><\/span><\/p>\n

Mars is brightest when Earth passes between the Red Planet and the sun. At such times, Mars is closest to us, and so it appears brightest in our sky. A similar situation occurs for Venus: the planet is brightest\u00a0around\u00a0the time Venus passes between us and the sun, but not exactly\u00a0at<\/em>\u00a0that time.<\/span><\/p>\n

Because Venus orbits the sun inside Earth\u2019s orbit, when it goes between us and the sun it\u2019s lighted hemisphere, or day side, is facing away from us. At such times, it\u2019s difficult or impossible to see Venus at all.<\/span><\/p>\n

Because it\u2019s an inner planet, as Venus approaches its time of passing between the Earth and sun, we see the planet exhibit phases, like a tiny moon. As Venus draws up behind Earth in orbit \u2013 and prepares to \u201clap\u201d us in the race of the planets \u2013 observers on Earth can watch as the phase of Venus wanes. Meanwhile, as the crescent Venus in waning in phase, the overall size of the disk of Venus gets larger in Earth\u2019s sky, as Venus draws closer to us and prepares to go between us and the sun.<\/span><\/p>\n

Venus is brightest when those two factors combine \u2013 waning crescent, plus largest overall size of Venus\u2019 disk \u2013 so that the\u00a0greatest amount of surface area of Venus\u00a0shows in our sky. Astronomers call this\u00a0greatest <\/em>illuminated extent.<\/span><\/p>\n

Source: Earthsky<\/p>\n","protected":false},"excerpt":{"rendered":"

Venus is\u00a0much\u00a0brighter than any other planet viewed in Earth\u2019s sky. It\u2019s the third-brightest object in the sky, after the sun and moon. Why is Venus so bright?\u00a0 As the planet next-inward from Earth in orbit around the sun, Venus is relatively nearby. But it\u2019s nearness isn’t the only reason Venus is bright. Consider that Mars […]<\/p>\n","protected":false},"author":6,"featured_media":2833,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-2832","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"featured_image_urls":{"full":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",800,595,false],"thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon-150x150.jpg",150,150,true],"medium":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon-300x223.jpg",300,223,true],"medium_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",750,558,false],"large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",750,558,false],"1536x1536":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",800,595,false],"2048x2048":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",800,595,false],"ultp_layout_landscape_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",800,595,false],"ultp_layout_landscape":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",766,570,false],"ultp_layout_portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",600,446,false],"ultp_layout_square":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",600,446,false],"newspaper-x-single-post":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",659,490,false],"newspaper-x-recent-post-big":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",484,360,false],"newspaper-x-recent-post-list-image":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",87,65,false],"web-stories-poster-portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",640,476,false],"web-stories-publisher-logo":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",96,71,false],"web-stories-thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2015\/02\/venus_moon.jpg",150,112,false]},"author_info":{"info":["Amrita Tuladhar"]},"category_info":"News<\/a>","tag_info":"News","comment_count":"0","_links":{"self":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/2832","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/comments?post=2832"}],"version-history":[{"count":0,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/2832\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media\/2833"}],"wp:attachment":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media?parent=2832"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/categories?post=2832"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/tags?post=2832"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}