because light from other stars takes time to reach earth...?

Question

does anybody think its possible that "aliens", from places that we cant see yet, are looking at the early earth? or will they just see a lump of rock, and try and find something more interesting to look at?

Answer 1

Who said, aliens exist in the first palce!

Answer 2

It would be difficult to see the earth from thousands of light years away, because it is so small and does not emit light. With more sophisticated sensing devices than we have it is of course possible that any beings there are out there could be examining earth, and they would be receiving signals from the past, because all of these would have a top speed of the speed of light.
This is what we do when we look at distant stars and galaxies, we look at what the universe was like thousands or millions of years ago. It has its uses, as it means we can have an idea of the history of the universe, how things have changed in time.

If these beings looked at the earth before there was life on it, they might find it interesting, they might think it had potential, they might send their seeding mission here to start up life as we know it. Maybe its happened already.

To tell the truth, I don't know any aliens, and I don't know what they would find interesting, or boring. Some PEOPLE find lumps of rock interesting.

Answer 3

Yes I do believe that may be the case. You might also think that we are overlooking them because of them same reasons. And as for the idea that if they can see us they can get to earth well just think of it this way we look at stars billions of light years away and we haven't even left our solar system.
But yes it will depend on how far away they are and if they even care that we are here. Because if they have the technology to visit us and there is indeed other life out there, you would think they would explore more near to their own planet to find life then come check out us. Although, you never know, they could already be here. Or on the other hand they may died out millions of years ago and we'll find their planet through a telescope in a few years and see the once great civilization. Its also sort of creepy because if we find there planet and see a space faring culture then its just as likely to think that a armada of evil aliens bent on taking our planet from us has been journeying for 10000 yrs and is almost at our doorstep and we would never know it.

Response to persons answer below myself.

Just because we think it is unlikely or even show buy current science doesn't mean it cant be done, look at how much our science books have changed in the last 200 yrs much less thousands. Also who says it has to be and optical light based system it could be some far fetched form of echo location maping everything on our planet with gamma rays.

Answer 4

It might be useful to give an idea of a "light year" here; a light year is the distance travelled by light in one year. So, a planet 5 million light years from us would, right now, be seeing the earth 5 million years ago ( in theory ).

They would of course be seeing the earth as it was and might not be very interested in it. Then again they might. But your point about seeing "back in time" is true, although there would be a lot of difficulties in seeing something so far away - it would be extremely faint and detail would be very poor indeed i.e. the aliens could see a planet, but not what was on it.

Answer 5

Radio transmissions have been spreading out from the Earth for about a hundred years; before Titanic, anyway. The sphere created by these transmissions, by a bizzare coincidence, is about 200 light years across. Within that sphere there are hundreds of stars, probably with thousands of planets.

Considering that life on Earth started in boiling, salt-laden seas after only 500 million years it is clear that the possibility of life under extreme conditions is much greater even than exobiologists gave credit for until very recently and the frequency of planet formation appears to be much higher than previously thought.

We can already tell what elements and simple compounds are present on planets in nearby solar systems; it's not much further to allow that more complex information is accessible by superior technologies, which we will ourselves develop presently.

Did the Australian bushman conceive of a rifle while practising with his throwing stick? I think not, but nevertheless such a thing was conceived, made and improved upon mercilessly in the Western hemisphere.

Answer 6

Light takes the same length of time in either direction, so if they're 200 light years away, they're seeing us as we were 200 years ago. That means they wouldn't pick up any radio or TV transmissions for some years yet, so they probably couldn't tell there was any civilization here. Of course, even from just a few light years away, picking up our broadcast signals would be extremely difficult because they would be so spread out.

What's more likely is that they could detect that Earth has water, oxygen, and carbon, and from that assume that the planet supports life. Our own technology isn't good enough yet to detect or analyze Earth-sized planets around other stars, but it is rapidly improving.

Answer 7

It could happen, because everywhere we look in the universe, we are looking backward in time. This is because the universe is expanding in all directions. This means that everything is moving further away from everything. As light travels through the universe, it can take millions of years to reach us, and because the light is almost like a picture of that fragment of time when it was first emitted (the photon, that is), we would be looking at the object, and it would look like as it was one million years ago. This means that if you look at Andromeda in the night sky, you are looking way into the past, and it would look entirely different if you were next to it, because the light would take hours to reach you.
This gives you an idea of the size of the universe, especially if you knew that the space between Andromeda and the Milky Way was so small, compared to the size of the universe, that it is totally irrelevant.

Answer 8

If we looked at a star which is 2,000 light years away then yes - we'd see what it looked like 2,000 years ago.

An alien in that star system looking at earth would also see what earth was like 2,000 years ago.

Earth has been interesting for many millions of years, as life exists here. Aliens in another galaxy (millions of ligth years away) might be watching the dinosaurs on earth.

Answer 9

There is no possibility that an alien on a planet of even the nearest star could construct an optical instrument with sufficient resolution to see life on earth. I could run the math to show this, but I'm feeling lazy today; do a bit of research on what an Airy disk is.

Answer 10

Depends on how far away they are. I haven't checked into it my self but I heard it said that radio and TV transmissions beam out into space. In a few years the earliest radio transmissions should be reaching the nearest stars.

Lets hope aliens haven't noticed us yet, and may not for quite some time.

Answer 11

yes, light takes time to travel across space, thats why they say when the hubble uses its long range telescope, that it is really looking into the past because the light it see's of other galaxies takes very long (hense light-years) to reach our point, so the hubble is seeing the ''old light'' of stars and galaxies,and its seeing what it Was that many light-years ago. so yes, i do think aliens on some distant planet look at our planet and see it as it was billions of years ago with no intelligent life, so they ignore us.