If we could see a planet in another galaxy. will we see it as it was billions of years ago?

Question

if so if live exist there now we wouldn't know?

Answer 1

Human beings are fascinated with the idea of a time machine–a way to shake off the bonds of the present and travel into the past or the future. No one has ever made a time machine, and scientists say it may be impossible–the very nature of the universe may prevent such “travel.”

But the sheer size of the universe means that light carries information from the distant past into our present, showing us what the cosmos looked like long, long ago and far, far away. When we look into the night sky–or even at our own Sun–we are seeing the past, not the present.

Here’s how it works. Light, the speediest thing we know of, zips along at 186,000 miles a second in the vacuum of space. Light leaves the surface of a star or planet, travels a great distance, and finally enters our eyes. We see the star or planet as it was–not as it is.

Our moon, for example, is about 240,000 miles away; it takes light about 1.3 seconds to travel from there to here. If something happened on the Moon–if it were hit by a big asteroid–we wouldn’t see the explosion until 1.3 seconds later.

The Sun is much further away than the Moon–about 93 MILLION miles. When light leaves the Sun, it takes 8 minutes to speed through space and reach Earth. If the Sun were to magically vanish, sunlight would continue streaming through our windows for 8 blissful last minutes, and the Sun would shine in its normal place in the sky. Finally, we would see the Sun wink out–480 seconds after it actually happened.

Relax–stars don’t suddenly disappear with a POOF. But over millions of years, stars do eventually become cold, dark cinders. So when we look out into the night sky, especially through a telescope, some of the glowing star s we see are actually dead and dark by now.

Why? After the Sun, the nearest star is 24 TRILLION miles away. Light must travel for 4 YEARS to cover that distance, so we are seeing the star as it appeared 4 years ago. Most stars are much further still; it takes their light thousands, millions, or even billions of years to reach Earth. So some stars that we see shining brightly through our telescopes may have actually burned out millions of years ago.

We may see one star as it appeared in 1803, another as it was in 3100 BC, and the next shining with light that left it 100 million years ago, when dinosaurs roamed Earth. The most distant stars–billions of “light-years” away–are a living snapshot of the early universe. Each star in the sky represents a completely different point in time. The night sky is a map of the past, and our eyes and telescopes are our own personal time machines.

Answer 2

yes, light travels at a constant speed, about three trillion miles per year. The reflected light doesn't change speed, eventually the light released in its original state will become visible when not disturbed by light polution.

Answer 3

Yes. Light travels at the speed of light, so the further away the planet is, the more of a window into the past it becomes. Unfortunately, you'd probably need an astronomical array half as big as the Galaxy in order to detect planets in other galaxies. We haven't directly observed any extra-solar planets inside our OWN Galaxy yet. They have only been inferred by the gravitational wobbles of their parent star.

You couldn't tell anything about a star that is more recent than the length of time it has taken the light to reach us, unless you have access to a faster-than-light drive, instantaneous interstellar communication, or a long range teleportation device. But then if you had any of these things, you'd quite possibly have a galaxy-wide telescopic array to show you images of extra-galactic planets....

We may, however, find hints of life existing on the planets of nearby stars - evidence of water and organic molecules would suggest we might want to send a probe to take a closer look. So, you'd have to wait a thousand years for our probe to arrive, and then another 4 years for the pictures to get back to you.

Unless aliens come round for a visit, that is going to be your best option...

Answer 4

Well it all depends on how far away the galaxy is.  If we could see an individual planet in the Andromeda Galaxy which is 2.52 million light years away, then the planet would look as it did around approximately 2.52 million years ago.  Now, if people on the other planet, in the year 2008, were looking at earth which was currently in the year 2008 also, then those people on the other planet would not see you and I and the way things are in modern times but they would see earth as it was 2.52 million years ago.  That is how light travel works.  186,200 miles per second across space.  Hope this answers your question.

Answer 5

If it's in another galaxy? Yes - although the closest galaxy is only a few million light years away. But if we're talking planets around stars that are nearby, then it's only as far away as those stars are - if we look at the exoplanets around Gleise 581, we'd only be looking twenty years in to the past, and if there's any planets around Alpha Centauri, only 4.2 years! (And anyone on Alpha Centauri could look back and see seventeen-year-old me looking up at the sky ^_^)

Answer 6

Correct! - although it may be millions as well. When we look out in space, we look back in time, because of the time that light took to reach us from there. The nearest significant galaxy - at least the near side of it - is a little over 2 million light years away. The light that we see from that galaxy took over two million years to reach us. So we see it as it existed over 2 million years ago.

Any events that we see occuring in that galaxy occurred over 2 million years in our past. We can see other galaxies as well - the farther away they are, the more distant we are seeing into the past. A decent backyard telescope can see galaxies that are over 60 million light years way - which means the light left there about the time dinosaurs became extinct here.  

Answer 7

Yes, In fact, it may no longer exist if you could see it as the light that left it would have been ages and ages ago and provided you could still see it, it woudn't be the same and could actually have cooled down and been extinguished by the time  you saw it.  

Answer 8

If it was billions of light years away then we would see it as it was billions of years ago.  If it is a thousand light years away then we see it as it was 1000 yeas ago.

We can only determine if there is life by exploration whether by robot ship or manned flight and that would take more than 1,000 years based on our present technology.

We cannot even fly at the speed of light yet.

We have just discovered water on Mars this past month by robotic analysis.

all that means is that life was possible, but we have no evidence that there was any intelligent life on Mars, yet.