Page 2 of 2

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

Posted: Wed Mar 13, 2013 3:01 am
by ta152h0
is there such a thing as a white hole yet ?

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

Posted: Wed Mar 13, 2013 4:35 am
by Chris Peterson
ta152h0 wrote:is there such a thing as a white hole yet ?
Only in abstract mathematics.

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

Posted: Mon Mar 18, 2013 5:32 pm
by 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

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

Posted: Wed Mar 27, 2013 7:47 pm
by 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.

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

Posted: Wed Mar 27, 2013 7:57 pm
by 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?

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

Posted: Wed Mar 27, 2013 8:19 pm
by Chris Peterson
Psnarf wrote: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.

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

Posted: Wed Mar 27, 2013 8:39 pm
by ta152h0
I have no fear revealing my weakness..Does the nucleus of an atom spin as fast as its electrons ?

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

Posted: Wed Mar 27, 2013 9:12 pm
by neufer
ta152h0 wrote:
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.)

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

Posted: Wed Mar 27, 2013 10:44 pm
by Chris Peterson
ta152h0 wrote: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.

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

Posted: Wed Mar 27, 2013 11:24 pm
by 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.

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

Posted: Wed Mar 27, 2013 11:32 pm
by 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.

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

Posted: Wed Mar 27, 2013 11:37 pm
by Chris Peterson
Beyond wrote: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.

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

Posted: Thu Mar 28, 2013 12:34 am
by Beyond
Chris Peterson wrote:
Beyond wrote: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.

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

Posted: Thu Mar 28, 2013 12:49 am
by ta152h0
this is spinning my head, but my head is not moving !

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

Posted: Thu Mar 28, 2013 1:02 am
by Chris Peterson
Beyond wrote: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.

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

Posted: Thu Mar 28, 2013 3:17 am
by Beyond
OK. Thanks... i think.

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

Posted: Sun May 05, 2013 2:18 pm
by neufer
Click to play embedded YouTube video.
http://www.spaceflight101.com/nustar-mi ... dates.html