When we look at the galaxy M31, do we see it the way it is today or what it was like at sometime in the past?

Answer 1

The light that reaches us left Galaxy M31 a long time ago, so we'd be looking into the past. Since it's about 2.9 light years away, we would see what was happening about 2.9 years ago.

Answer 2

M31, otherwise known as the Andromeda Galaxy, is about 2.5 million light years away. The light we see from it LEFT M31 2.5 million years ago - so what we "see" is that old light.
When we look at it, we are seeing events which occurred there 2.5 million years ago.

Think about this - light travels about one foot in a billionth of a second. so when you see someone across the room, from ten feet away, you are "seeing" them ten-billionths of a second in the past. Way too short for a human to notice, but that is something to think about. The farther away something is, the farther into its past you are observing it.

When astronomers use powerful telescopes and other instruments to peer to the farthest edges of the universe, they are seeing 12 billion light years away, and that means they are seeing things that happened 12 billion years ago, long before the earth was even formed!

Hope this helps you!

OC

Answer 3

We see it's past
because the lgiht was sent millions of years ago and it takes that long to get here. same thing for the sun
it takes the sun's light 8 minutes to get to earth.. so if the sun burned out ( which it wont) it would take us 8 minutes to realize it
so if the galaxy is millinos of LY away
it could not even be there anymore but we would have no clue until millinos of more yers bc its past light is still reaching us

Answer 4

As it was in the past, the time in years being equal to the distance in light years from Earth.

Answer 5

You see it at the point the light left it. If it is, say, 5 LY away, you are seeing it as it was 5 years ago.

Answer 6

we se it as it was millions of years ago, because that's how long it takes for the light to reach us.