Man, it’s like walking up to your three-month old car and seeing that first ding in the door panel. No, it doesn’t affect the function any but it’s still annoying.
That’s why “they” use the term observable universe and thanks to the apparent acceleration of the expansion, that actually is getting smaller and smaller. In the inconceivably distant future, long after the Sun is a cold cinder, that observable limit will be the local super group, then our galaxy, then whatever’s left of our solar system.
The sad part is that barring FTL (good luck with that) we can never, ever know what’s beyond that observable limit. The cool part is that in a way, the heliocentric people were right: We are at the center of the (observable) universe.
The JWST can see – I dunno – 13.5-bly in every direction. If we were to instantaneously transport it 10-bly that way we wouldn’t see an edge 3.5-bly that way and an infinity in the direction back towards home, we’d still be in the enter of a sphere 13.5-bya in radius.
It’s not expanding from somewhere it is to somewhere it’s not. It’s always where it is. It’s just that it’s expanding where it is.
Somewhere or another (in the massive piles of “teaching stuff”) I have a couple of transparencies I made to help illustrate this. One of them is a random scattering of dots, represent galaxies (or stars, or any other objects of interest in the Universe). The other one is the same exact image, but blown up 10%. Put one on top of the other, and you can match up any one dot you want, and no matter which one you match up, all of the other dots appear to be moving away from that one point.
And now we can imagine that, instead of 8.5" by 11" slides, I had infinite sheets of transparency material. Even though both are infinite, I could still have one that’s an enlargement of the other, and spaces between dots would still be greater, and any point could be lined up as the “center” they’re expanding from.
Webb does it again … this is the Cartwheel Galaxy, about 500 million light-years away, the result of a collision between a conventional spiral galaxy and a smaller galaxy.
Well, for certain definitions of “violent”. It’s not like stars are smashing into each other. A collision of galaxies means slow gravity interactions over hundreds of millions of years.
In fact, although the merger is not going to be finalized for another 5-billion years, the Milky Way’s collision with Andromeda has already begun!
The Andromeda galaxy, our Milky Way and other galaxies all sit enshrouded in a large envelope – called a galactic halo – which consists of gas, dust and stray stars. The halos of galaxies are faint, so faint, in fact, that detecting them is not an easy feat.
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[I]t’s the faint halos of the galaxies that indeed appear to have started to touch one another. Thus, in a manner of speaking, the collision between our two galaxies has already started.
True, but it could well be considered “violent” on cosmological timescales, since those gravitational interactions completely transform the configuration of both galaxies. Also, presumably the two supermassive black holes merged, an event violent enough to create significant gravitational waves.
Yeah, was going to say but forgot, the Cartwheel Galaxy’s appearance is a real pleaser. Usually when two galaxies get done colliding and merging with each other all you’re left with is a boring ol’ elliptical galaxy.
