Did You Know? .....Neutron Star..

[ToraToraTora]

If the Earth were to be compressed to the density of a Neutron star it would be 305 metres in diameter.

[New Judge]

Far worse than that - if it collapsed further to form a Black Hole it would be around the size of a plum.

[Ken4155]

Far worse than that. If The Doctor hadn't stepped in, the Earth would have been wiped out by The Flux!

[ToraToraTora]

technically judge it would be zero but the event horizon would be the size of a plum.

[New Judge]

But I cannot get my head round infinite density, Tora. I think there is far too much emphasis on tying this up with the speed of light and time and all that. If something exists with the mass of the Earth (or of anything else for that matter) it must occupy some space, however small.

[Atheist]

NJ better go and do some more research. Anyway, as Dick Feynman said, anyone who thinks they understand quantum physics obviously doesn't.

[New Judge]

Explain to me, then, in simple terms, how something with mass can occupy no space at all. I'm all ears.

[Kardashev]

New judge, it makes no sense but it is mathematically accurate. With enough mass gravity can overcome the nuclear force and matter can be crushed out of existence. Essentially it becomes infinitely dense in zero space.

[Bazile]

Far worse than that .
Can you imagine the left and right on here having to be in such close proximity?

[Atheist]

NJ; I can't explain in any terms.
:-)

[New Judge]

//With enough mass gravity can overcome the nuclear force...//

Yes I know that. But the matter that remains after the space in the individual atoms has been eliminated still has mass and it must still occupy some space. The notion that it can be "crushed out of existence" is absurd. If it is crushed out of existence it will no longer have any mass, will not have infinite density, and will exert no gravitational influence on anything around it. From observations that does not seem to be true. I think it's a case of "have a look out of the window" (wise advice in both weather forecasting and when flying aircraft). Just because your sums tell you something might happen, it does not mean that it can or will.

[New Judge]

And I forgot to add that something with infinite density will also exhibit an infinite gravitational force and will suck everything else in the universe (however distant) into it - something else which does not seem to have happened if you look out of the window.

[Kardashev]

I know it makes no sense but that's what a singularity is zero space, infinite density of the mass that went into creating it. Essentially the Maths leads us to an area where our understanding and reasoning break down. The search for a a GUT is about resolving these issues where physics breaks down the unification of the quantum world and the day to day word may yield understanding in the future.

[Kardashev]

"And I forgot to add that something with infinite density will also exhibit an infinite gravitational force " - no the gravity is not infinite because the mass is not infinite. If a large enough star collapses then matter cannot resist gravity and the singularity is formed with the mass that's there.

[davebro]

Maybe the answer is that matter does not in fact exist as something solid & incompressible - at the extreme of gravity it becomes pure energy.

What is mass - no matter
What is matter - no mass (to mis-quote Homer Simpson!)