{"id":42873,"date":"2023-03-15T14:24:44","date_gmt":"2023-03-15T14:24:44","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=117098"},"modified":"2023-03-15T15:32:31","modified_gmt":"2023-03-15T15:32:31","slug":"how-long-does-it-take-for-light-from-the-sun-to-reach-earth","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/how-long-does-it-take-for-light-from-the-sun-to-reach-earth\/","title":{"rendered":"How long does it take for light from the Sun to reach Earth?"},"content":{"rendered":"

The answer is either 8 minutes 20 seconds or thousands of years, depending on how you look at it! <\/p>

By Russell Deeks\n \t\t<\/p>

Published: Wednesday, 15 March 2023 at 12:00 am<\/p>

\n\n

It takes light from the Sun 8 minutes and 20 seconds to reach us on Earth \u2013 on average.<\/p>\n

That\u2019s the simple, straightforward answer \u2013 but whatever the razor-toting Mr Occam<\/a> may tell you, the simple, straightforward answer seldom tells you the whole truth.<\/p>\n

In this case, there are two factors that complicate the picture.<\/p>\n

Firstly, the answers that it takes light from the Sun 8m 20s to reach Earth is derived by dividing the distance from the Sun to Earth \u2013 around 150 million kilometres \u2013 by the speed of light<\/a>, which is around 300,000 km\/s (kilometres per second).<\/p>\n

That\u2019ll give you a journey time of some 500 seconds, or eight minutes 20 seconds.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
When we bask in sunlight, it\u2019s taken that light 8 minutes 20 seconds to travel to our planet from the centre of the Solar System. Credit: Peter Cade \/ Getty Images<\/span><\/figcaption><\/div>\n

However, as Earth\u2019s orbit around the Sun<\/a> is slightly elliptical rather than perfectly circular, the actual distance between our planet and the big fiery globule of burning gas that gives Earth light and heat can be anywhere from 147 to 152 million kilometres.<\/p>\n

So light\u2019s actual journey time from the Sun to Earth can be anywhere from 490 to 507 seconds, or 8m 10s to 8m 27s.<\/p>\n

Secondly, the answer above is how long it takes for any given photon of light to journey from the Sun\u2019s surface to that of Earth \u2013 but that\u2019s not the whole story.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
A diagram showing how Earth orbits the Sun. Credit: Adrian Dean<\/span><\/figcaption><\/div>\n

Photons of light, you see, aren\u2019t formed at the Sun\u2019s surface: they\u2019re \u2018made\u2019 deep inside the star and because the Sun is, to quote Douglas Adams, \u201cvastly, hugely, mind-bogglingly big\u201d, it can take them thousands or even tens of thousands of years to reach the surface of the Sun, before they embark on their 8m 20s journey to Earth.<\/p>\n

This means that while the photons of light coming your computer or screen that enable you to read this article are just nanoseconds old, those that hit your eyes when you step outside on a sunny day actually began their journey several thousand years ago.<\/p>\n

Which is a bit longer than 8m 20s.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Photons of light, thwarted by those pesky humans! Credit: Shunli Zhao \/ Getty Images<\/span><\/figcaption><\/div>\n

And which, as a side note, is why shadows are inherently funny.<\/p>\n

Imagine being born inside a star, spending thousands of years fighting your way to its surface, bravely traversing millions of miles of interplanetary space and battling through Earth\u2019s atmosphere all the way down to the ground\u2026 only, after all that effort, to have your plans thwarted by a lamp post or wheelie bin!<\/p> <\/body><\/html>\n

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The answer is either 8 minutes 20 seconds or thousands of years, depending on how you look at it! <\/p>\n","protected":false},"author":24,"featured_media":42874,"template":"","categories":[1],"acf":{"readingTimeMinutes":"3"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/how-long-does-it-take-for-light-from-the-sun-to-reach-earth.jpg",1200,800,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/how-long-does-it-take-for-light-from-the-sun-to-reach-earth-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/how-long-does-it-take-for-light-from-the-sun-to-reach-earth-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/how-long-does-it-take-for-light-from-the-sun-to-reach-earth-768x512.jpg",768,512,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/how-long-does-it-take-for-light-from-the-sun-to-reach-earth-1024x683.jpg",800,534,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/how-long-does-it-take-for-light-from-the-sun-to-reach-earth.jpg",1200,800,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/03\/how-long-does-it-take-for-light-from-the-sun-to-reach-earth.jpg",1200,800,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"The answer is either 8 minutes 20 seconds or thousands of years, depending on how you look at it!","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/42873"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/42874"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=42873"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=42873"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}