2007-01-07 02:36:23 · 21 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Everything you see you see in the past as it takes time for the light that an object reflects or gives off to reach your eyes. Then it takes more time for your mind to process that information. Even something as close as your nose is seen as it was because of this fact. (It is a very short time to see where your nose was when you look at it but it still take some time.)
Stars due to the distance they are from earth take a minimum of 8 minutes for their light (the sun in this case) to reach your eyes so you can see it. Others take at least 4 years (the next nearest star) and up to the 14 billion years (the age of the visable universe) to reach us. So we see them as they were when that light was given off instead of how they are now.
If you want to see what a star looks like right now just wait a few years (or billions) that new look will get to earth for you to see. It just takes some time.
2007-01-07 02:45:26 · answer #1 · answered by my_iq_135 5 · 0⤊ 0⤋
Because as every body told you the light takes time to reach the earth, if a star explode today in a place 10 light years from earth it will take the light of the explosion 10 years to reach the earth, so in 10 years from now you will see the star exploiting. that is why the sky you see every night is a kind of time machine, the light of the stars you see every night probably was traveling for 100 years and may be that star it doesn't exist anymore.
If you can travel faster that the speed of light (hyphotesis) you will see the earth turning in the opposite direction and if you reach the end of the universe you will see the big bang.
2007-01-07 03:53:12 · answer #2 · answered by Santiago Beau.. 2 · 0⤊ 1⤋
When light emits from a star it takes quite a while for us to be able to see it. So by the time it takes for that light to reach your eyes the star is already in the past. Even the sun you look at is in the past. If the sun stopped shining now, you would still see it for exactly 8 minutes and 33 seconds.
2007-01-07 02:45:22 · answer #3 · answered by manc1999 3 · 0⤊ 0⤋
Because light travels at a finite speed. Therefore we see the star as it was when that light reaches us. If the star is 10 light years away, that means it takes 10 years for the light to reach us. Whatever light we see was "sent" 10 years ago. If we are ever able to travel out to the stars at high speed, it will be similar to traveling through time. Not only will we get closer, but we will see light that was sent out from a star more recently, showing us a sped up evolution of that star.
2007-01-07 02:40:13 · answer #4 · answered by Pylon 2 · 0⤊ 0⤋
because of the time it takes for the light to reach earth, if a star was 1 year away from earth and exploded tonight, it wouldn't be seen for 1 year. for example, if you wanted to know what would happen if the sun exploded? you have to look at the following questions and answers. How far does light travel in one second ? 300 000 kilometers, which equals seven times around the Earth. Let's call this distance one light second. We can use this as a ruler to measure distances in space. Beyond the Sun and its planets we need a longer ruler, which is the distance light travels in one year. This is called a light year - it is 32 million times longer than a light second. Multiplying a light second by the number of seconds in a year, we can answer the question:
How far is a light year? 10 trillion kilometers (or more exactly, 9.5 x 1012 km). How far is the Earth from the Sun ? 500 light seconds or 8 light minutes, so you see, if the sun exploded now, we'd all be dead in eight minutes time.
2007-01-07 06:27:59 · answer #5 · answered by tribalgirlie 2 · 0⤊ 0⤋
Actually, you see everything as it was in the past. Look at your hand. The photons that are bouncing off it and into your eye left an infinitesimal fraction of a second ago. Photons from the sun take 8.3 minutes from the point they leave there to your eye.
Nearby stars are light years away. Our galaxy is about 100,000 light years across. Other galaxies are millions and billions of light years away.
2007-01-07 02:47:24 · answer #6 · answered by gebobs 6 · 0⤊ 0⤋
Because we see by means of light, which moves at around 300,000 kilometres per second. The nearest sun is Proxima, in the triple star system of Alpha Centauri, which is around 4.3 light years away, so it could have just exploded (extremely unlikely) and we would not know for 4.3 years. Many other stars are thousands or millions of light years distant!
2007-01-07 02:47:28 · answer #7 · answered by CLICKHEREx 5 · 0⤊ 0⤋
Light travels at 186,000 miles per second . The nearest star to Earth other than the sun is 4.5 light years away ,
This means that we are seeing that star as it was 4.5 years ago .If that star were to supernova today, we would not know it for another 4.5 years .
2007-01-07 02:46:31 · answer #8 · answered by rocknrod04 4 · 0⤊ 0⤋
Because when we look at them we are actually seing the light reflected by them not the star itself . As the light travels from such a great distance it can take millions of years to reach the point where we can see it from Earth.
2007-01-07 02:44:23 · answer #9 · answered by D B 6 · 0⤊ 0⤋
Its because light traveling 185000 miles per second. You see what like at the moment light left the object ie a star or planet.
2007-01-07 03:41:52 · answer #10 · answered by CLIVE C 3 · 0⤊ 0⤋