Biggest ever seen black hole jets; blasting plasma well beyond their own galaxy • Hacker News Board

Re: Biggest ever seen black hole jets; blasting plasma well beyond their own galaxy

#81

Post by ASalazarMX » Mon, Sep 23, 2024, 5:34 PM UTC

mkl wrote: post #56

dyauspitr wrote: post #45

Earlier quoted context omitted.

The whole concept of the Big Bang is a mind warp. The whole explosion must have happened in some… space-time thing to begin with. What was that immense point of matter and energy in? What was “around” it? We’ll never know.

It wasn't an explosion. Space itself expanded, so there wasn't anything to expand into. https://en.wikipedia.org/wiki/Expansion_of_the_universe

I think there are some philosophical definitions in the way. The Universe is everything we know, it is made of space and time, so of course it cannot expand into any space as it contains all of it.

We don't know what's outside the Universe, so we can't say there is nothing, and we can't say there's anything, we don't know what it is expanding into, or if "expansion" even makes sense outside the Universe. If we somehow find out what's outside the known Universe, that will inevitably become part of the known Universe, so we will never know what's outside the Universe.

Re: Biggest ever seen black hole jets; blasting plasma well beyond their own galaxy

#82

Post by kadoban » Tue, Sep 24, 2024, 7:52 PM UTC

thehappypm wrote: post #76

kadoban wrote: post #53

Earlier quoted context omitted.

It will gain energy. There _is_ no amount of energy it could gain to escape though. It goes no faster, gets no closer to escape. It just splats into the black hole and we'll never see it again no matter how much energy it started with or gained.

From an outside observer, the black hole is finite in width though, though. and if the speed of light is constant, isnt that a contradiction? Or is a black hole somehow of infinite width?

It's not a contradiction because the path of the light enters the black hole event horizon but does not come back out.

All paths end at the ~center of the black hole. We don't really know what's there, at the so-called singularity at the center, it may be impossible to know. But it's probably something that light can hit and stop existing, or even if it can't it'll be stuck there in some way or another.

We know that the gravity (warping of spacetime) around a black hole is such that it cannot escape, even at light speed. What happens inside is less sure, but largely moot because none of it can ever affect anything outside of the event horizon ever again.

(Hawking Radiation or something else may make this technically a lie, but it's close enough to the truth to last a few trillion years)

Re: Biggest ever seen black hole jets; blasting plasma well beyond their own galaxy

#83

Post by kadoban » Tue, Sep 24, 2024, 7:58 PM UTC

thehappypm wrote: post #79

hollerith wrote: post #78

Earlier quoted context omitted.

It is finite in circumference, yes, but its geometry is not the usual geometry so diameter does not equal circumference divided by pi.

It must be infinite then?

Maybe. Nobody really knows what happens at the center. General relativity I believe says "yes", but nobody knows how true it is in the case of ~infinitely dense crap in an infinitely small spot. Usually "infinite" means what really happens is not captured by the model, but nobody has a better answer yet as far as I know.

A better answer would be something like a grand unified theory of gravity and the other forces, including quantum effects, which doesn't exist. It's like the holy grail of physics, you'd be the next Einstein if you figure it out.

Re: Biggest ever seen black hole jets; blasting plasma well beyond their own galaxy

#84

Post by edgyquant » Wed, Sep 25, 2024, 4:18 AM UTC

dyauspitr wrote: post #67

edgyquant wrote: post #63

Earlier quoted context omitted.

Instead of thinking of it as a bang in an existing space-time, the way to conceptualize it is the collapsing of a universal wave function from a superposition of all possible universal states. Of which our universe is just one potential possibility. Space time is a function of the collapsing state.

I think I understand that to a certain extent. But where does the universal wave function exist to begin with? There must be some construct it exists within.

Why? I would look at Occam’s razor, believing there must be an outer layer (or a creator of god) just leads to an infinite regress. It’s much more likely that the thing is just eternal according to that logic