Looking back in time....

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Coffman

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I took an introduction to Astronomy about 4 years ago at a college. The professor said that when we are looking up into space, we "actually looking BACK INTO TIME" (ie. the past). He said that light only travels so fast and that we are seeing the images (light) that was emitted from stars in the past.
This got me thinking; (scary thought i know :lol: ) I know it is against the laws of speed or physics or something like that (hey Im a Psychology major, dont judge), but *IF* you took a satellite with a video camera attached, and put it into space traveling away from our planet at a speed *GREATER THAN LIGHT* :eek: , then turned it around to look back at our planet, you could theoretically look into our past right????
Kinda a weird thing because if possible you could zero in on a specific place on the planet and.... for instance determine who is at-fault in a collision, or verify historical accounts...
Any thoughts?

-btw, i'm not sure if this site is even the place to be posting something like this, so no flaming me ok?

Jason Coffman
 
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weeman

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Hypothetically, yes you could use this to verify historical events.

If you were an alien species who lived on a planet that was 65 light years from Earth, and had a miraculously powerful telescope, you could look down on the surface of Earth and be viewing the tail end of World War II. This is due to the fact that even though it is 2010 on Earth, the light you are seeing from Earth was given off during WWII. Even the light we see from our own sun is 8 minutes old!

This is why cosmology/astronomy is one of the trickiest sciences, because you can't study anything as it's happening. Nearly 100% of everything you study has already happened; most of which happened billions of years ago!

This is why Earth-based experiments, like particle accelerators, are so helpful to scientists. Because they can get instant results and information about how the fundamental constituents of the universe behave.
 
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ramparts

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No, even hypothetically that's impossible. Sorry. The reason is that nothing can travel faster than the speed of light, and for some very good reasons. So once a signal - say, a broadcast of the 10th inning of Game 6 of the 1986 World Series - has left into space, there's nothing we can do to go get it back... except, I guess, hope some aliens find it, record it, and then ask them about it much later. This is why Tivos are a good idea ;)

Also, I'd add that this is why cosmology and astronomy are able to do as much as they are. So much of cosmology, especially, is about working out what happened in the past, and we don't have to make nearly as many guesses when we can actually see what happened in the past (but in a different part of the Universe).
 
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amshak

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Coffman":sps3rrtr said:
I took an introduction to Astronomy about 4 years ago at a college. The professor said that when we are looking up into space, we "actually looking BACK INTO TIME" (ie. the past). He said that light only travels so fast and that we are seeing the images (light) that was emitted from stars in the past.
This got me thinking; (scary thought i know :lol: ) I know it is against the laws of speed or physics or something like that (hey Im a Psychology major, dont judge), but *IF* you took a satellite with a video camera attached, and put it into space traveling away from our planet at a speed *GREATER THAN LIGHT* :eek: , then turned it around to look back at our planet, you could theoretically look into our past right????
I think what Proffeser ment was tight in one way.-
when we are looking up into space, we "actually looking BACK INTO TIME" (ie. the past). You know a light from a star requires Years to come to the Earth. Ex- A light from The star star Serious requites 7years , Some stars- 10 ,15, 50, or may be 75 years to reach Earth So If You look in that way Your Professer is right. :D
 
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MeteorWayne

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The star is Sirius, and it is 8.6 light years away.

Our sun is 8 minutes and 24 seconds away in light time, so where you see it, is where it was that long ago!

On a dark night, with your unaided eye you can also see the Andromeda Galaxy, which is 2.5 million light years away.
Of course, with telescopes, you can see galaxies even further away.
 
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weeman

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ramparts":2b49d3en said:
No, even hypothetically that's impossible. Sorry. The reason is that nothing can travel faster than the speed of light, and for some very good reasons. So once a signal - say, a broadcast of the 10th inning of Game 6 of the 1986 World Series - has left into space, there's nothing we can do to go get it back... except, I guess, hope some aliens find it, record it, and then ask them about it much later. This is why Tivos are a good idea ;)

Also, I'd add that this is why cosmology and astronomy are able to do as much as they are. So much of cosmology, especially, is about working out what happened in the past, and we don't have to make nearly as many guesses when we can actually see what happened in the past (but in a different part of the Universe).
I was simply referring to the idea that if you looked back at Earth from a certain distance, you would see Earth as it was 'x' amount of years ago in relation to your 'x' distance in light years from Earth.
 
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Coffman

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weeman":1zfmb2hj said:
ramparts":1zfmb2hj said:
No, even hypothetically that's impossible. Sorry. The reason is that nothing can travel faster than the speed of light, and for some very good reasons. So once a signal - say, a broadcast of the 10th inning of Game 6 of the 1986 World Series - has left into space, there's nothing we can do to go get it back... except, I guess, hope some aliens find it, record it, and then ask them about it much later. This is why Tivos are a good idea ;)

Also, I'd add that this is why cosmology and astronomy are able to do as much as they are. So much of cosmology, especially, is about working out what happened in the past, and we don't have to make nearly as many guesses when we can actually see what happened in the past (but in a different part of the Universe).
I was simply referring to the idea that if you looked back at Earth from a certain distance, you would see Earth as it was 'x' amount of years ago in relation to your 'x' distance in light years from Earth.
weeman- thanks for the answer
ramparts- perhaps I was not clear enough in my O.P., but I perfectly aware of the fact that according to theory nothing can travel faster than the speed of light. I was simply asking a "hypothetical" question just for fun. :D
 
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