APOD: Spin up of a Supermassive Black Hole (2013 Mar 12)

[ta152h0]

is there such a thing as a white hole yet ?

[Chris Peterson]

is there such a thing as a white hole yet ?

Only in abstract mathematics.

[Luis]

The illustration does not look the way a back hole is descrobed. If the matter is being sucked up at the speed of light, the image looks like a peaceful lake, the matter needs to be shown thinned down as it approaches the black hole in a spiral motion. The image looks too nice to describe such a chaotic and tremendous activity

[Psnarf]

Speculation has it that a white hole exists at the other end of a black hole. Instead of drawing everything in, it spews stuff out. Them pesky physicists sure can get wacky sometimes.

[Psnarf]

We still don't know what gravity is, so how can we speculate on the contents of a massive gravity well? How do we know anything gets past the Schwarzschild radius? Can we measure the mass of the accretion disc? What does infinite curvature of space-time mean?

[Chris Peterson]

We still don't know what gravity is, so how can we speculate on the contents of a massive gravity well? How do we know anything gets past the Schwarzschild radius? Can we measure the mass of the accretion disc? What does infinite curvature of space-time mean?

I'd say we understand gravity very well- about as well as we understand anything.

[ta152h0]

I have no fear revealing my weakness..Does the nucleus of an atom spin as fast as its electrons ?

[neufer]

I have no fear revealing my weakness..Does the nucleus of an atom spin as fast as its electrons ?

The proton, neutron & electron all have the same spin angular momentum: ħ/2

They also all have roughly the same sorts of orbital momentum in an atom/nucleus : nħ (for relatively small n).

(But this is probably not what you are asking about.)

[Chris Peterson]

I have no fear revealing my weakness..Does the nucleus of an atom spin as fast as its electrons ?

In addition to Art's response, it is worth keeping in mind that "spin" is a quantum mechanical concept, which through angular momentum is analogous to classical spin of an object. But neither the nucleus nor electrons physically spin in a classically meaningful sense.

[ta152h0]

you are just like my father, who answered with riddles and you had to figure out by yourself. One of them took 30 years. He named his boat 7-11 and for the life of me I could not figure that out until after his passing. It was the solution of a simple equation that described the age difference of his kids. Inside that equation was another equation and bothe of them surfaced at the same time. I myself left a few of these " bombs " to go off sometime in the future for my own kids.

[Beyond]

So what you're saying, Chris, is that if i stand perfectly still on earth, i am spinning. Not only because the earth is spinning on it's axis, but because the earth is also spinning around the sun, and the sun is also spinning around the Milky Way, ECT. But i don't notice all that spinning, because it is tooo Big, and i am tooo small.

[Chris Peterson]

So what you're saying, Chris, is that if i stand perfectly still on earth, i am spinning. Not only because the earth is spinning on it's axis, but because the earth is also spinning around the sun, and the sun is also spinning around the Milky Way, ECT. But i don't notice all that spinning, because it is tooo Big, and i am tooo small.

No, I'm saying that neither atomic nuclei nor electrons spin in the sense we think of "spinning". Nothing to do with scale.

[Beyond]

So what you're saying, Chris, is that if i stand perfectly still on earth, i am spinning. Not only because the earth is spinning on it's axis, but because the earth is also spinning around the sun, and the sun is also spinning around the Milky Way, ECT. But i don't notice all that spinning, because it is tooo Big, and i am tooo small.

No, I'm saying that neither atomic nuclei nor electrons spin in the sense we think of "spinning". Nothing to do with scale.

I didn't mean to imply that 'scale' had anything to do with the spinning. It's just to show that even if a human was standing still, he would still be spinning, but not in the way that we normally think of spinning. So if what i said doesn't come close, then you will hafta splain what kind of not normal spinning you mean.

[ta152h0]

this is spinning my head, but my head is not moving !

[Chris Peterson]

I didn't mean to imply that 'scale' had anything to do with the spinning. It's just to show that even if a human was standing still, he would still be spinning, but not in the way that we normally think of spinning. So if what i said doesn't come close, then you will hafta splain what kind of not normal spinning you mean.

What I mean is that electrons and other subatomic particles aren't spinning. They don't physically rotate about some axis. What we call "spin" in this case is a quantized quantum mechanical parameter related to another QM concept only loosely related to the classical concept of the same name, angular momentum.

[Beyond]

OK. Thanks... i think.

[neufer]

Click to play embedded YouTube video.

http://www.spaceflight101.com/nustar-mi ... dates.html