2007-01-26 05:11:20 · 11 answers · asked by quaninter 2 in Science & Mathematics ➔ Astronomy & Space
Light travels at a certain speed. ( 299,792,458 m / s to be precise). A light year is a measure of distance which is equivvalent to the distance travelled by light in one year. When we look at our universe, there are distance stars and galaxies that are millions of light years away. That means.....the image (light) of the stars that we are looking is actually several million years old. So its like looking at the past.
So if we are currently looking at a star that is, say 75 million light years away, we looking at something that existed 75 million years ago. It might be still there or may be not. Ofcourse a star life time is several billion years. Thats how we can study the past just by observing the distant objects in our universe.
2007-01-26 05:17:05 · answer #1 · answered by Trivi 3 · 1⤊ 1⤋
we already see what the universe was like in the past. Depending on how many light years an object is away from our position - the light we see was made that many years ago. If an object is a thousand light years away we are looking a thousand years into the past.
After awhile of taking in telemetry data from periodic observations we can statistically draw conclusions on an object's position and properties. whether those conclusions are for the future or the past.
2007-01-26 05:22:03 · answer #2 · answered by voxninerbox 2 · 1⤊ 0⤋
Light moves fast, but it does have a finite speed. That said, when we look out into the universe, we are seeing back in time.
When we look at the sun, we are seeing the sun as it looked 8 minutes ago. When we look at Alpha Centari, we see it as it looked about 4 years ago. When we look to the very 'edge' of the universe, we are seeing back as far as we can - light emitted by anything further out hasn't had enough time to reach us yet.
2007-01-26 06:11:17 · answer #3 · answered by Justin 5 · 1⤊ 0⤋
When you look up into the sky you are looking back in time.
Light from distant galaxies takes hundreds and thousands of years to travel here. What we see now is what was happening then. Those galaxies have moved on and changed by now. We won't know what happened to them for thousands of years more.
Hubble space telescope took some pictures of distant galaxies, some 14 billion light years away. Just now their light is reaching us. That's what they looked like 14 billion years ago. For all we know they may be dead now.
2007-01-26 05:21:21 · answer #4 · answered by tercir2006 7 · 2⤊ 0⤋
Look up.
The light you see from the stars originated there some billions and even trillions of years ago. The fascination would be to see the universe as it is now.
2007-01-30 03:02:42 · answer #5 · answered by Costy 3 · 0⤊ 0⤋
When you see the Andromeda galaxy for instance, you are seeing it as it was 2.5 million years ago. That's because light travels at 186,000 miles per second. By the time you see something far, far away in space, it has already happened a long, long time ago.
2007-01-26 06:50:06 · answer #6 · answered by Count Acumen 5 · 1⤊ 0⤋
By building a time machine and traveling to different dates in history.
2007-01-30 00:06:37 · answer #7 · answered by pnn177 4 · 0⤊ 0⤋
We cannot. Not the whole universe at least.
Only localized records with varying levels of accuracy.
2007-01-26 05:21:23 · answer #8 · answered by J C 5 · 0⤊ 1⤋
Look into the sky and you look into the past due to the finite speed of light.!!!
Th
2007-01-26 05:21:55 · answer #9 · answered by Thermo 6 · 1⤊ 0⤋
Look thru a telescope, the bigger the better.
2007-01-26 11:40:26 · answer #10 · answered by usarmysgtmom 1 · 0⤊ 0⤋