how do we see stars? as they are or as they ONCE were?

Question

i read somwehere that the stars we see are actually ver old, since it takes their light millions of years to reach us. i'm so confused!! help!

Answer 1

The light from stars can take thousands to millions of years to reach us, so in effect, when you look at a star, you are seeing it as it was in the past.

For example, say the light from a star, because of it's distance, takes 1 billion years to reach us. We would say this is 1 billion light years away. When you look at the star, you are seeing light from that star that was made 1 billion years ago. The light that is leaving this star right at this moment, will not reach us for another billion years. (That is assuming the star is moving with us so there is no relative motion. In other words it's not moving closer or farther away.)

Answer 2

think about sound for a second. if someone is dribbling a basketball 100 yards away from you, you can see it happen before you hear it. the guy dribbling the basketball hears it right when the ball hits the ground. thats because it takes time for the sound to reach your ear.

its the same basic thing with light. right now, light is being given off by a star 4 light years away. a "light year" is the distance light travels in a year. the light moves away from this star in all directions. when we look in the direction of the star that is 4 light years away we will not see the light it is giving off right now for 4 years because it takes 4 years for the light to move that far. but 4 years from now we will look up at the same star and what we will see is the light it has given off 4 years earlier, which is today. so when you see a star you see the light it gave off 4 years ago and if you could suddenly be right next to the star, you would see what you could see on earth 4 years from now.

Answer 3

Close. We see everything as it was when light left it, because the speed of light is finite. Usually, this is of no importance -- it takes the light from this screen only a nanosecond to reach your eyes. But the nearest star is four light years away, and the visible stars are as much as several hundred light years away, so the light you see tonight has been traveling for that long.

Answer 4

Nothing you see is as it is, but as it once was. Light travels you-know-how-fast, which amoung other things is about 1 foot per nanosecond, so even looking at your monitor is looking a billionth or 2 seconds into the past. So you could say your monitor is "one or 2 light-nanoseconds" away from you. The moon is about 1.2 light-seconds away (220,000 miles/(186,000 miles-per-second)), the sun is 8 light-minutes away, Pluto is several light-hours away, the nearest star is 4 light-years away, and pretty much every star you can seen with the naked eye, those in our immediate neighborhood of the galaxy, are from about 4 to a couple thousand light-years away.

The center of our galaxy looking toward Sagitarius is around 50,000 light-years away. On a clear night away from cities, you can see our nearest neighbor galaxy, the Andromedea galaxy, which is about 2 million light-years away. Billions of other galaxys, consisting of billions of stars each just like ours, are much further away. The furthest objects in the universe are around 15 billion light-years away, so when you look at them, you are seeing them not as they are now, but what they looked liked shortly after the Big Bang, 15 billion years ago.

Does this do it for you? All in all, the finite speed of light results in your NEVER able to see anything EXACTLY as it is "now", but instead at some time in the past.

Answer 5

Well, if the star is 20 light years away it takes the light 20 years to get to you so what you see is the way it looked that long ago.

Answer 6

Both as they are AND as they once were.

You do see our Sun, yes?

Now, the Sun is a star; you do see it as it is, or at least insofar as the speed of light does allow you to see the Sun in a time as close to real time as possible.

The speed of light is considerably fast and at once considerably slow. Since light has mass, it carries in no less way than anything that is of mass while moving through infinitely distant empties, and 'recording' what once was and not necessarily what still exists.

The speed of thought moves at a rate much, much greater than that of the speed of light. This takes us into the areas to what many will call 'fancy' and imagination... But -- it is real !

The moment you can focus your thought on a point in space, you at once are there... whereas by the means of lightning speed, travel does take " light years " to arrive at that same destination.

Such as this is why the astro-scientists, philosophers, poets, and theologians are verily now coming into common agreements as well as sheer awe.

Answer 7

O.K., Everything we see is as it was in the past, how much in the past depends on how long it takes the light either reflected or generated by the object to reach our retinas and of course there is also the delay of our nervous system. What I think you really need is to understand the scale of our universe... The star that is closest to us is the sun it is about 93,000,000 miles away. The next closest star is much farther away, so far away that to measure it in miles would result in an unreasonably large number, so distances of this magnitude are measured by how long it takes light to traverse that distance. It takes light from the sun 8 3/4 minutes to reach us, light from the next nearest star takes 4.3 YRS. There are about 20,000,000,000,000,000 stars in our galaxy. There are hundreds of galaxies in a group and there are hundreds of thousands maybe millions of groups in the visible universe. Light from some objects has taken over 10,000,000,000 yrs to reach us.