When we look up at the sky we are looking into the past so how do we know that those stars are actually there?

Question

when we look up into space, we are looking into the past about 3,000 years ago, the reason we are looking that far is because even thought light travels 186,287 miles per second we are so far aaway that it takes 3,000 years to get here, wow. so remember when you look at space you are looking 3,000 years into the past so how do we know that some of those stars and planets are still there?

Answer 1

Not all stars are that far away. The brightest star in the sky, Sirius, is only 9 light years away. We see it as it was 9 years ago. Mars is only a few light minutes away, we see it as it was a few minutes ago.

Stars (like the Sun) last millions of years at least. So 3,000 years is nothing in the life of a star. But technically, Sirius could have gone out 8 years ago and we wouldn't know it for another year. But stars just don't go out like that. None has ever been seen to just go out like that and everything we believe we know about stars would have to be wrong if that could happen.

Answer 2

Not all of the stars you see are still there. Of course, this applies more to someone looking through a really good telescope in an area with no ambient light.

If a star explodes or is absorbed today and it is 100 light years away, we, on earth, will see the light for 100 more years.

If our sun were to extinguish we would see the light for just over 8 minutes.

Finally, we are looking one He$$ of a lot farther back in time than a mere 3,000 years.

With the proper equipment we can see between 14 and as much as 20 billions of years in the past. Science is happy with about 14 billion + / - for the age of the Universe but it could be closer to 20 B. In other words, scientists can now look almost to the very beginning of the Universe, just nanoseconds after the Big One which was really a very small one with no sound so “Big Bang" is a catchy name but not a good description.

Answer 3

A star like the Sun burns for a few BILLION years !
Even the light from the Sun we see hear on earth is 8 minutes old. It gets even more fun, the light we see in a telescope looking at Saturn first has to travel from the Sun to Saturn and reflect back to earth - total time is close to 2 hours. Of course it depends on how close Saturn is, if it's on the far side of the sun we can only see it for a short time just after sun set and the time for the light to make the trip is much greater.

As far as your question - NOTHING is where we see it !
As explained above light takes time to get here. so we see things where they were in relation to where we are now. There are millions of stars that we "see now" that have long since blown up! A supernova seen in 2000 was about 12 million years old when it's light reached the earth.

There are Galaxies we see Billions of years away ! but they have traveled thru space for those billions of years and are even further away now.

Answer 4

We don't know if those stars are still there or not.

But stars evolve slowly, so even a few thousand years isn't long enough for a star to suddenly disappear without some prior observations to hint at something about to happen.

But not all stars are 3000 light years away. Our galaxy is 100,000 light years across, and the Andromeda Galaxy is 2.5 million light years away. And the furthest object the Hubble Telescope has imaged is about 11 billion light years.
We don't know that any of those are "really" still there at this moment or not.

Answer 5

why are you so particular about this 3000 years? I am just curious because you gave so much importance to that number. It is possible that somebody fed you with a wrong information that all stars are 3000 light years away from us.

Also the space we look is not one single layer. So it cannot be of the same distance from us. It has a depth and we see stars from different depths ( distance ) from earth.

Proxima centauri star is only about 4 years from earth. Then there are strs at different depths. It would have been great if somebody could tell us what is the most distant star we could see with naked eyes? did anybody tell you that by naked eyes we could see a star actually located 3000 light years from us? If so thanx for that information.

With telescopes we could look into billions of light years from us, but it would be great if somebody could tell us what is the most distant individual star we could see by any telescope. Not the whole galaxy, only the individual star. It will be also interesting to find out what is the most distant galaxy we could see by naked eye?

By naked eyes I think we could only see stars of our milky way galaxy. The next one of the nearest galaxies is andromeda, and by naked eye we cannot see any individual stars of that galaxy but only the whole galaxy.

It is quite possible that we could see by naked eye a star which is located 3000 light years away from us in our milky way galaxy. May be that is the most distant star we could see by naked eyes. I am sure 3000 light years corresponds to milkyway galaxy itself not out side it's range, so your statement makes sense.

Anyway when we look into space we are looking from 8 minutes and before that. Sun is the nearest star and 8 minutes away for light to reach us. From 8 minutes - then it is about 4 years ( centauri star system- alpha centauri, proxima centuari etc ) then I suppose next star is Sirius which is about 8 light years and the distance keeps on increasing. Of course this is star dependent light. When you look into moon the light takes only few seconds to reach earth ( reflected light ).

In the space everything is toooooo biiiiiig and vaaaast. Space is such a big place beyond any imagination. But space objects/ space happenings also corresponding are very big or very loooong. For example the stars live for extremely long time in billion years. So 3000 years is really nothing fror this huuuuge space/ universe. It is really nothing. So nothing usually happens in 3000 years. There is a pattern for anything. Things do not happen just like that in space. Ceratain things need lot of time to happen. A star will dye slowly over million to billoion years. So the stars we see at 3000 years away from us are most likely still existing now ( with some exceptions ).

However if we see a star million or billion years away then it is possible what we are seeing now may not be existing. Nothing can easily destroy a star, it usually dies by itself, or very rarely by black holes. Eitherway it is a looong process. But planets can dye quickly. A very big asteroid of several thousand miles can hit a planet and destroy it almost immediately.

Answer 6

We don´t. We just don´t know if the stars are still there. Just imagine the sun, if the sun explodes tomorrow, we would realize it only 8.5 minutes after the actual explosion.

Since the stars are much more distant, they may have exploded many years ago and don´t exist anymore, but we will realize it when the light of the explosion comes to the Earth.

An example of this happened in 1987, when the supernova 1987A exploded. We saw it in 1987, but this explosion had occurred 170,000 years ago, because the distance of the star was 170,000 light years in one of the Magellanic Clouds.

Answer 7

Planets are very close compared to the stars. We may not know if they are all there, but we know they all were there yesterday. With the stars, we don't know. Stars are burning out, and new stars are forming all the time. The further away a star is, the bigger the chance that it may not still be there.

Answer 8

Some of those stars may not be there because it is true that we see the past, so we do not know if they are there or not. But many of the stars we see are still there; planets too.

Answer 9

of course some have blown up--the red giants-you see that millions of lite years ago--probably have gone Nova--stay tuned we well see in a few million years

Answer 10

We don't. They're not in the direction we see them. And some are not in existence.