Someone once told me whilst looking through a telescope that the stars i'm looking at are actually not in realtime but what they looked like years ago,if this is so.If something was to look from that star to the earth will they see an early earth?
2006-07-25 13:22:34 · 21 answers · asked by accuratellytrue 2 in Science & Mathematics ➔ Astronomy & Space
the stars are no longer there, been dead thousands of years so yes it they were to look from a star u see in the sky, the view would be from a cpl of thousand years ago
2006-07-25 13:25:57 · answer #1 · answered by onename 4 · 0⤊ 0⤋
yes, have you heard the term light year? When you look at the stars in the sky you are looking at what it looked like hundreds and thousands of years ago since it takes hundreds and thousands of years for the light from the star to travel. So logically if someone was to look at the earth, then depending on their distance they would not have the view that we are in right now.
Example, the sun is the closest star to the earth and it takes about 8 minutes for the sun's light ot reach the earth so therfore when we look at the sun we are looking at the way it looked 8 minutes ago and not in real time.
2006-07-25 20:47:51 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Yes, all stars (with the exception of the sun) are very far away, light years away.
Since light travels at light speed (exactly 299,792,458 m/s in a vacuum), it takes time for the light emitted by stars, or reflected off of planets, takes time to travel to Earth and into your telescope.
In one year, a beam of light will travel a distance of 1 light year.
It will take light 1 year to travel 1 light year (commonly abbreviated ly).
The closest star to Earth (besides the sun) is Proxima Centauri at a distance of 4.21 ly...meaning that the light we see from this star is 4.21 years old.
The sun is about 8 light minutes from Earth...meaning that it takes 8 minutes for the sun's light to get to Earth after it leaves the surface of the sun.
It also works in reverse, not only are we seeing "old" light from stars, the stars are receiving "old" light from Earth....so yes, if there are any aliens around some other star looking through their telescopes at Earth, they would see an old version of Earth.
2006-07-25 20:34:54 · answer #3 · answered by mrjeffy321 7 · 0⤊ 0⤋
What you are seeing is the light from the stars and planets and such. Since light travels through space at 186,000 miles (300,000 kilometers) per second and the planets are billions of miles away, you can do the math.
So yes...Someone sitting on a planet a billion miles away or so will see Earth as it was about 100 years ago.
2006-07-25 20:31:23 · answer #4 · answered by moose_skinner 2 · 0⤊ 0⤋
Well the truth is of course that they won't be able to see the earth but our sun as you can't really see planets from other star systems (although we can surmise that they are there from the slight 'wobble' they cause on the sun they circle). Essentially though your premise is correct. The light from our star in prehistoric times could very well just be reaching stars millions of light years away just as we may be viewing stars that have long since exploded or been extinguished...cue twighlight zone music.....
2006-07-25 20:28:54 · answer #5 · answered by powkesmore 2 · 0⤊ 0⤋
Yes. It's because we see using light, and light only travels at 186000 mi./sec. The closest star is Proxima Centauri, which is a little over 4 lightyears away. That means that it would take a little over 4 years to travel from here to there (or from there to here) at the speed of light. Since the light arriving here from Proxima Centauri traveled for 4 years, we therefore see it as it was 4 years ago. Andromeda (the closest galaxy) is about 2000000 lightyears away, so we se what it looked like 2000000 years ago.
2006-07-25 20:29:47 · answer #6 · answered by David F 2 · 0⤊ 0⤋
technically we never see exact realtime, we see at the speed of light since the receptors in our eyes see based on light. So the stars you were looking at is not at realtime they are seen at the time it takes for light to reach earth from their possition and it takes up to over 6 years for light to reach us from some stars. (proxima centura for example takes 6.3 years)
So if you were there looking here you would see earth 6-7 years ago. (They know its 6.3 years because they send a signal there and it took 12 and a half years to bounce back)
2006-07-25 20:34:57 · answer #7 · answered by B.R.E 2 · 0⤊ 0⤋
yes. It's all to do with the time light takes to get from where it starts(the star) to here. Light travels 186,000 miles per second but the stars are much further away than that so it takes many years to get to earth. The same would go in reverse.
2006-07-25 20:28:27 · answer #8 · answered by Thinker 4 · 0⤊ 0⤋
This is precisely what happens. Not only are the stars ancient history, but our very own sun's light is also history. The sun is 93,000,000 miles away and it takes about 8 1/2 minutes for its light to reach us.
The stars out there are thousands and millions of light years away. The distance of one light year is (brace yourself) 5,865,696,000,000 (5.87 trillion miles away). That's just 1 light year, now think about the objects that are 1,000 and even 1,000,000 light years away.
INCONCEIVABLE!
2006-07-25 20:31:51 · answer #9 · answered by Borat Sagdiyev 6 · 0⤊ 0⤋
Of course Yes. Light takes time to travel from one place to the other. Nearest star is about 4.5 light years away. Therefore if some one looks at us from the nearest start they will be looking at sun 4.5 years ago. Not the current one.
2006-07-25 20:24:43 · answer #10 · answered by st_creations2003 2 · 0⤊ 0⤋
yes, light travels at a speed of 3x10^8 m/s and teh stars are so far away.
they would need a bloody good telescope to see cavemen is thats what you're getting at, they would see a flicker in our suns light which is our planet passed between their planet and our sun if they were lucky, though our sun may not even exist for some people who see the light that is emitted from it today
2006-07-28 07:26:19 · answer #11 · answered by Dirk Wellington-Catt 3 · 0⤊ 0⤋