B Question about deep space pictures

[gleen41]

So I have a random question with all these talks of the pictures released from NASA by JWST. So these galaxies, stars, etc, are like 40 million light years away, so that light must've left these galaxies 40 million years ago, which means things have obviously changed. So are there any tests or processes to predict what is happening now to objects that far away? Or would that require bigger and more powerful computers to basically simulate the universe based on physics we know?

I tried googling this but I don't even know how to word my question lol. Hopefully this makes sense to people that know astronomy WAY better than I do. Apologies in advance for not knowing how to word stuff!

 

[FactChecker]

So I have a random question with all these talks of the pictures released from NASA by JWST. So these galaxies, stars, etc, are like 40 million light years away, so that light must've left these galaxies 40 million years ago, which means things have obviously changed. So are there any tests or processes to predict what is happening now to objects that far away? Or would that require bigger and more powerful computers to basically simulate the universe based on physics we know?

I tried googling this but I don't even know how to word my question lol. Hopefully this makes sense to people that know astronomy WAY better than I do. Apologies in advance for not knowing how to word stuff!

The observations of the farthest (and earliest) objects will tell us more about what happened long ago, but we already have a lot of observations of the more recent (and closer) behavior of similar objects. We can see stars, galaxies, dust, etc. at different times in the past as they are closer or farther away. The theories of how things progress as time passes are based on those observations. We can then apply those theories to the farthest things observed to estimate what has happened since.

 

[Halc]

So are there any tests or processes to predict what is happening now to objects that far away?

No different than predicting what our own galaxy might look like in 40 million years. Perhaps easier with the distant galaxy since our view of our own is painful due to seeing most of it edge-on.
Still, one can see the nearby objects and predict collisions and such. Andromeda is going to collide with the Milky way in 4-5 billion years, less time than the age of our planet. But we cannot yet predict where our solar system will end up due to that event.

The beauty of the distance is our opportunity to see into the past. The further away you look, the more you get a glimpse of the state of our young universe. There's little reason to speculate how those galaxies have changed since then, and their current age is frame dependent anyway.

 

[Ibix]

So are there any tests or processes to predict what is happening now to objects that far away?

There is no way to know what's happening now, no, because nothing can get here faster than light to tell us.

You can do some prediction, although how much very much depends what you want to predict. 40 million years isn't much in the lifetime of most stars, so we wouldn't expect huge changes - some will have died, some will have ignited, all will be older, but most of the same stars ought to be there. Where they are is another matter - galaxies don't spin rigidly and stars move relative to their neighbours as they interact gravitationally. So I wouldn't expect the stars to be in the exact same layout, but there's no way we have enough information to write a detailed simulation. At 40 million light years I doubt we're resolving individual stars, let alone measuring their masses.