Looking at the stars in the sky = time travel to the past?

Question

what i mean is lets say a star is 250ligth years away from earth the means it took 250years for the ligth to reach earth so that exact same star may not even exist today but we still see it like it does is this true theory?are we really looking back in to the past?

Answer 1

Yes. If that star is 250 light years away, the light from that star would have taken 250 years to reach the Earth in the first place. Therefore the light we see is the light that was there 250 years ago. So yeah, when you look into the night sky, you look into the past.

Answer 2

"When you look out into the night sky, you're seeing the stars because of the light that has traveled from them to you.  It takes time for the light reach you.  Imagine you're looking at a star that is 6,000 light years away.  You're seeing that star as it was 6,000 years ago. Space and time are related.  ...The further you look out through space, the further you look back in time."

You have a total amount of motion.  Motion through space and motion through time.  Their total together is a constant: c.  If you have more motion in one part, you have less through the other.  So, the faster you move through space, the slower you move through time.  Even on the shuttle, however, at its [relatively] slow speed of about 17,000mph, the difference from a stationary observer on the earth to the astronaut's time is billionths of a second.  You have to be moving at a substantial percent of the speed of light to see any noticeable effects of time dilation.

Answer 3

yes.

so what? the speed of light has been known to be finite for 350 years.

Answer 4

Yes, and it is all out of our meddling reach .. thankfully.

Answer 5

well i could say yes, we looking back to past.

any star you see now is not living anymore, is only the spot of light traveled all those years to reach our eyes.

Answer 6

Yes, we are seeing what that star looked like 250 years ago.  This isn't really time travel, since we can't go back and do anything, it's more like looking at old photographs.

Answer 7

It's a good bet that a star 250 light years away is still there (albeit slightly shifted in position), looking pretty much like it did back then.  Even thousands of years is not enough time to change the appearance of most stars.  But when you see stars hundreds of thousands or even millions of light years away, there's a good chance they look different up close than the delayed image we're seeing.  Especially red giants - really big stars use up their fuel quickly, some explode too...      

Answer 8

^ Right. In fact, the Hubble telescope has been watching light from stars and planets from millions of years ago - so i guess in a way it is time travel, if you think about it as viewing the past.