RedSteadEd

RedSteadEd t1_itn0q4z wrote

Reply to comment by AcidShAwk in Webb reveals unprecedented glimpse of merging galaxies. Because light takes time to travel to us, when we look at objects like this one in the very distant regions of the universe, we're seeing light that was emitted about 11.5 billion years ago by Wagamaga

>11.5b years for the light to reach us.. Our physical position in space was not here 11.5b years ago. We would have been a lot closer to to wherever this light originated.

Imagine throwing a baseball at somebody, but you're both running backwards away from each other. That's basically what's happening, but on a bigger scale - light is traveling from the galaxy to us, but the space between us is always expanding.

>Does that mean it's taken 11.5b years for that light to finally overtake our position ?

Yes. The image we see when we look at the galaxy left the galaxy 11.5b years ago and carries with it a picture of what the galaxy looked like back then. However, when that light was created 11.5b years ago, the galaxy would have been much closer than 11.5b lightyears. Imagine if I was standing next to you and then traveled instantly to that galaxy. You might think that it would take 11.5b years for you to finally see me (that's how long it would take for the light to reach our original position), but that doesn't factor in how much the space between us would expand during those 11.5b years of travel. The light would have to keep going beyond the 11.5b years to reach you, but I don't know the math, so I can't tell you how much further.

>What have we taken images from literally 180 degrees from that image above to view 11.5b years from the completely opposite direction?

I'm not sure if I understand this... yes, we have pictures facing the opposite way in the universe that also have light that originate from 11.5b years away. Or, are you asking what it would look like if, 11.5b years ago, someone in that galaxy took a picture of us?

>I'm trying to understand at what point we look at ourselves and say there is light from 11.5b years ago.. in every direction

As I understand it, this is part of how we know the universe is expanding - there's light (well, radiation) coming towards us from every direction that's almost as old as the universe. It's called the Cosmic Microwave Background.

6