1st image of James Webb Space telescope(JWST)

[freyar]

I believe most of those are very distant, very red-shifted, very young galaxies.
Webb is about 7x bigger than Hubble, so it can just see fainter things with shorter exposure times. But I believe the main reason Webb but not Hubble sees them is because Webb detects longer wavelengths of infrared, so it sees redder objects-- including very distant, very red-shifted galaxies.

Another reason those distant galaxies tend to be redder is that they're younger and tend to have more dust (often around star forming regions).

As for numbers, the foreground SMACS 0723 cluster is apparently around 4.6 billion years old (and in distance terms, I believe that means it's pretty close to 4.6 billion LY away). The most distant of those red ones in the background are up to 13 billion years old (but i'm not sure how that translates to distance).

I know there are some real astronomers, etc, around here who could probably correct/expand on any of this!

Here's NASA's PR on the image:

NASA’s Webb Delivers Deepest Infrared Image of Universe Yet - NASA

NASA’s James Webb Space Telescope has produced the deepest and sharpest infrared image of the distant universe to date. Known as Webb’s First Deep Field, this image of galaxy cluster SMACS 0723 is overflowing with detail.

www.nasa.gov

I am not sure how far it was actually when the light spend 4.6 billion light years to get to us. At the time it left its origin, I think it would have been closer than 4.6 billion light years away, but due to the expansion of the universe, the distance the light needed to travel was actually 4.6 billion light years. And of course, since then, the object moved further away from us, too, so it's definitely not 4.6 billion light years away from us now, either. It might be now so far away that the light leaving it now will never reach us.

This can be all quite confusing.

Not an astronomer.

The 4.6 billion lyr distance for SMACS 0723 is about the farthest distance where the light travel time and the "proper distance" --- meaning the distance if you could somehow measure it all right now --- are still about the same. Any farther away and you have to start accounting for relativity better. The farther (13 billion year old) galaxies are 40 or more billion lyr away if you could measure it right now.

On Mustrum's other point, the SMACS 0723 galaxies should be visible more than 5 billion years into the future. If the expansion of the universe does come to be controlled by a cosmological constant (which some people debate), they will move out of view, but that would be at least 13 billion years from now.

I'm not an observational cosmologist, but I do work in related areas sometimes.

 

[Horwath]

1st image of an explanet with JWST:

link for the article:

NASA’s Webb Takes Its First-Ever Direct Image of Distant World – James Webb Space Telescope

blogs.nasa.gov

 

[Art Waring]

Somewhere in the heavens, they are waiting...

 

[Ryujin]

Lots of videos on Youtube about how images from Webb have now invalidated this or that theory. Very click-baitey. It's getting annoying to have to wade through them, to get to some real science.