# Would I have a shadow on Pluto? **URL:** \ **Category:** Factual Questions\ **Created:** [September 21, 2009, 5:53pm UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966 "2009-09-21T17:53:16Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [September 21, 2009, 5:53pm UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966/1 "2009-09-21T17:53:16Z")
I read in a work of fiction than in Pluto the Sun is nothing more than a very bright star in the sky but that it is still strong enough to cast a shadow of someone standing on Pluto’s surface. Is this true? If not, where is the farthest it would? ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [September 21, 2009, 6:10pm UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966/2 "2009-09-21T18:10:14Z")
You would have a shadow, but it might not be very distinct (since everything would be pretty dark). It gets about 1/1000th the sunlight Earth does. While dim, that’s still 450x brighter than Earth’s moon appears to us. I’m not sure where you’d stop having a shadow… it would probably be at the point where average starlight was more or less equivalent to the sun’s. Since stars are millions of times fainter, you’d have to go pretty far out. ---
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [September 21, 2009, 6:12pm UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966/3 "2009-09-21T18:12:32Z")
Well, the moon can most definitely cast visible shadows. 450 times brighter should create very distinct shadows. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [September 21, 2009, 6:21pm UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966/4 "2009-09-21T18:21:44Z")
At its maximum brightness, Venus can cast shadows (on Earth). ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [September 21, 2009, 7:14pm UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966/5 "2009-09-21T19:14:21Z")
[http://www.gsfc.nasa.gov/gsfc/educ/science/2000/02-01-01.htm](http://www.gsfc.nasa.gov/gsfc/educ/science/2000/02-01-01.htm) > [@](#): > > from Pluto the Sun would have a magnitude of approximately -20. From Earth, the Sun has a magnitude of -26.7, whereas, the brightest star we can see in the Northern Hemisphere, Sirius, has a magnitude of -1.4 and Venus can attain a magnitude of -4. Thus, the Sun from Pluto would be more than a million times brighter than Venus looks like from Earth and 1,000 times brighter than our full moon! Definitely a shadow thrower. ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [September 21, 2009, 8:01pm UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966/6 "2009-09-21T20:01:17Z")
> [@ZenBeam](#): > > At its maximum brightness, Venus can cast shadows (on Earth). Really? _googles_ [Whoa!](http://science.nasa.gov/headlines/y2005/28nov_venusshadows.htm) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 21, 2009, 8:57pm UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966/7 "2009-09-21T20:57:52Z")
Also note that the shadows on Pluto would be somewhat faded, but they’d be extremely sharp. The fuzziness you see around shadows, especially those cast by objects far away, is caused by the angular size of the Sun in the sky. Since the angular size of the Sun is much smaller from Pluto, the shadows will therefore be sharper. ---
**Author:** ![Freddy\_the\_Pig](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@Freddy\_the\_Pig](https://boards.straightdope.com/u/Freddy_the_Pig)\ **Post date:** [September 21, 2009, 9:14pm UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966/8 "2009-09-21T21:14:11Z")
> [@Sapo](#): > > If not, where is the farthest it would? Venus makes a good marker for the limit of brightness at which an object will cast shadows visible to the human eye. The Sun would be as bright as Venus if viewed from 28,840 A.U.'s–about a tenth of the distance to Alpha Centauri. ---
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [September 22, 2009, 8:44am UTC](https://boards.straightdope.com/t/would-i-have-a-shadow-on-pluto/510966/9 "2009-09-22T08:44:20Z")
> [@bup](#): > > Really? > > _googles_ > > [Whoa!](http://science.nasa.gov/headlines/y2005/28nov_venusshadows.htm) Amazing.