Images in light years and traveling in light years…


The Hubble telescope captured an image 230 million light years away. It was an image of two galaxies colliding 230 million years ago.

If I had a space ship that contained FTL technology and traveled 230 million light years into that direction, my understanding is that it would look completely different from the image that was captured by Hubble.

**I guess my question is… how do we get that image from 230 MILLION years ago only just now? My brain wants to view it as a physical photo that flew over here because I just can’t wrap my head around how an old image could reach us.**

** FYI: I read through [this ELI5 thread on light years]( and I still don’t really get it. Maybe I’m just stupid :/

In: Physics

7 Answers

Anonymous 0 Comments

> how do we get that image from 230 MILLION years ago only just now?

Light moves at a finite speed, so it takes time to arrive.

Maybe you have already seen fireworks or lighting from far away (like a few miles). You might have noticed that you hear the bang some time after you see it. That’s because sound is slower than light. If you were blind, you would perceive the bang only a few second late.
The same thing happens with light, except that we are observing stuff that is ridiculously far (trillion trillions miles), so it takes millions of years for light to reach us.

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