2006-07-08 13:19:50 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
If you know how many light years away a star is, that will tell you how long light takes to travel from the star to reach the earth, and therefore how old the image of the star is. The sun, for example, is only 8 minutes away. Sirius, which is bright and close to us is 8.6 light years away. Orion is 1500 light years away, so when we look at it, the image is of what the constellation was like in 506 AD.
2006-07-08 13:32:09 · answer #1 · answered by Coco 2 · 0⤊ 0⤋
It's how many light years it is. 1 light year=1 Earth year. If a star is 10 light-years away, the light it's putting out right now will reach Earth in 10 years.
2006-07-08 21:09:20 · answer #2 · answered by tkron31 6 · 0⤊ 0⤋
It depends on how near (or far) the star is from us in light years (the time light travels in an earth year). First you need to know that, then the image is that number of light years away.
2006-07-08 21:02:16 · answer #3 · answered by Pandak 5 · 0⤊ 0⤋
It depends on how many light years away it is, for example Uranus, (I know it's not the star but it's a good example) when you look at Uranus you're accually seeing it as it was 4 minuets ago because that's how long it took the reflected light to reach Earth. Same thing with stars, it depends on how long it took for the light to reach Earth.
2006-07-08 20:42:46 · answer #4 · answered by suppy_sup 3 · 0⤊ 0⤋
Depending on distance is correct, just an added note....It takes light to reach us from the sun in about 8 1/2 minutes. Jupiter is 8 hours, Uranus is a lot longer than 4 minutes.
2006-07-09 00:05:26 · answer #5 · answered by orion_1812@yahoo.com 6 · 0⤊ 0⤋
When looking at a star...lets take "Arcturus" as an example...you are looking at "light" that the star emmitted 32 years ago. Arcturus is estimated at about 32 "light-years" distance from our Solar System. The distance of our solar system from edge-to-edge is called an "Astronomical Unit"...an "AU". Light, travelling at the speed of 186,000 miles per second, travels 63,240 AU's in one year. So looking at Arcturus, which is 32 light-years distance from us, when we look at the star today, we are actually and in fact, looking at light which Arcturus emmitted 32 years ago. Let's say that the star "exploded". We here on earth wouldn't "see" the explosion of Arcturus for another 32 years from now. That's a facinating thing to think about...don't you think?
2006-07-08 20:49:51 · answer #6 · answered by LARRY M 3 · 0⤊ 0⤋
It depends on how far away the star is, for instance if the star is one light year away, then it will take light one year to get to us, then we will see the star. If the star is 40,000 light years away, it will take 40,000 years before anyone will see the light that's emitted from it.
2006-07-08 22:47:36 · answer #7 · answered by lilfireyballofhate 3 · 0⤊ 0⤋
as many ears ago as the time it takes the light to reach you. for ex if a star is 4 light yrs awy, u r seeing as it was 4 yrs ago
2006-07-08 21:16:02 · answer #8 · answered by savvy s 2 · 0⤊ 0⤋
Depends on how far away it is!
2006-07-08 20:22:34 · answer #9 · answered by tattie_herbert 6 · 0⤊ 0⤋