Black holes and new elements

[g99]

I posed this in one of the other threads on black holes but it was kind of passed over.

If i am incorreect in anything please say so.

Black holes take in all forms of matter and do not let anything escape right? Compression=heat and fusion right?

So if all matter inside is compressed to a infetesimal size, won't you have a runaway reaction inside of the black hole that continuously fuses heavier and heavier elements? Could we get in due time new elements beyond the 100 something we curently know of?

What happens if a black hole dissapates? Will these new theretical elements be blown out into the universe or just stay where they are?

[Glom]

I think that by the time it's gotten to the black hole stage, the realm of nuclei has passed.

[Colt]

Also, as I understand it, we are not even sure if matter is compressed once it goes in. We can not tell what happens. Quoting some video we watched in Astronomy: "Physics breaks down in a black hole." -Colt

[Vermonter]

I read in my intro to astronomy textbook that when matter is taken into a black hole, it breaks down into base particles. Everything goes into the singularity which comprises the mass of the black hole due to the gravity, IIRC. So no, we don't get heavier elements, just a singularity, I think.

When a black hole dissapates, the matter floats around the universe and probably recombines into elements or energy.

[CthulhuBob]

Just another thought from a self-confessed dilettante;

As you get above 100 in the periodic table the half-life of the elements decreases dramatically. I seem to remember they were able to create particles of element 140(?) but last mere nano-seconds. SO if elements were recombined to higher states in BH and it did dissipate before the universe died then those elements would most likely disappear very quickly.

So does this make sense?

[Vermonter]

Yes, it makes sense. Unless we had the equipment needed, we wouldn't be able to detect or observe the new elements before they vanished.

[Celestial Mechanic]

[Snip!]As you get above 100 in the periodic table the half-life of the elements decreases dramatically. I seem to remember they were able to create particles of element 140(?) but last mere nano-seconds.[Snip!]

There was a claim that element 114 had been created recently but it was retracted. I believe that the highest element to be created is either 110 or 111.

It is believed that there may be an island of stability somewhere around 114/118/126 (no one seems to know where just yet) where the half-life could be longer, maybe even long enough to do some chemistry!

[Celestial Mechanic]

Just a reminder, black holes are surprisingly simple because only a few properties can be measured: mass, angular momentum, electric charge, temperature and entropy. This is colloquially summarized as "A Black Hole Has No Hair". In particular, this means that a black hole does not have a baryon number (or a lepton number), this information is just "lost" when matter falls in. The missing information appears as the entropy of the black hole. Since a black hole has no baryon number, we can't speak of it as being a big nucleus of element 3.1416 x 10^70!

[Vermonter]

Also, I think the term "black hole" is a sort of misnomer. Black holes are ultra-dense collapsed stars. They are spherical in shape, and there are two kinds: nonrotating (Schwarzschild) and rotating (Kerr). In both you have extremely simple structures, the event horizon and the singularity. Kerr black holes have a doughnut-shaped region, located just outside the event horizon, called the ergoregion at which nothing can remain at rest.

I believe there is a theory that there is a supermassive Kerr black hole at the center of the Milky Way Galaxy, and most likely in the centers of other Galaxies as well.

Why not call them black stars? That's essentially what they are. They have no real color due to the fact that the star's gravity sucks the photons back in on itself, and it eats up matter that is sucked into it.

But riddle me this: since black holes trap even light, how is it that we can detect them by their X-ray signatures?

[russ_watters]

Why not call them black stars? That's essentially what they are. They have no real color due to the fact that the star's gravity sucks the photons back in on itself, and it eats up matter that is sucked into it.

That would probably be a better name. But careful with the "sucks" thing. Its not correct and leads to problems like this:

But riddle me this: since black holes trap even light, how is it that we can detect them by their X-ray signatures?

They don't suck in or trap it per se. They just are so massive they can emit no light of their own. So a photon that flys by just past the event horizon isn't "sucked" in. And a piece of hot matter just outside the event horizon emits light that isn't sucked in either. And its the emissions of matter falling into the black hole that we detect. Through the combination of the energy of particles as the cross the event horizon and the gravitational redshift, it was calculated that such matter would emit x-rays. And x-ray sources with no associated star were some of our first indications of black holes being more than just a mathematical oddity.

[Vermonter]

Why not call them black stars? That's essentially what they are. They have no real color due to the fact that the star's gravity sucks the photons back in on itself, and it eats up matter that is sucked into it.

That would probably be a better name. But careful with the "sucks" thing. Its not correct and leads to problems like this:

But riddle me this: since black holes trap even light, how is it that we can detect them by their X-ray signatures?

They don't suck in or trap it per se. They just are so massive they can emit no light of their own. So a photon that flys by just past the event horizon isn't "sucked" in. And a piece of hot matter just outside the event horizon emits light that isn't sucked in either. And its the emissions of matter falling into the black hole that we detect. Through the combination of the energy of particles as the cross the event horizon and the gravitational redshift, it was calculated that such matter would emit x-rays. And x-ray sources with no associated star were some of our first indications of black holes being more than just a mathematical oddity.

Ok, I wasn't aware of that. ops: It makes sense that the matter that falls into the black star would be red-shifted. But why would it emit X-rays? Is that because the wavelength is decreased due to the speed of the matter falling past the event horizon?

But you're right. Black stars don't emit visible light because of the mass. But there are photons emitted, however, the photons would fall right back into the black star. Hence no light. In my textbook, it says that Kerr black stars rotate several thousand times per second. The stars also grab the region of space-time and make that rotat too .

[David Hall]

It makes sense that the matter that falls into the black star would be red-shifted. But why would it emit X-rays? Is that because the wavelength is decreased due to the speed of the matter falling past the event horizon?

My understanding has always been that the x-ray signatures we see come from rings of swirling matter (usually hydrogen gas pulled off of companion stars) in orbit around the BH. As it gets slowly pulled down into the gravity well, friction and tidal forces heat it up, causing it to emit lots of energetic radiation, mostly in the form of x-rays.

[Glom]

I've just noticed something. g, you asked an intelligent question. Well done. How does it feel? :wink:

[Grey]

Since a black hole has no baryon number, we can't speak of it as being a big nucleus of element 3.1416 x 10^70!

As I mentioned in another thread, though, you can think of a neutron star that way. Above a certain mass, the gravitational binding energy is what makes it stable again. It should be more or less electrically neutral, but I expect you could easily knock off a few electrons (or have it absorb a few protons) and get various new elements. Of course, they'd be really weird isotopes, since the neutron count ends up around 10^57 and the proton count would be much, much smaller than that. And of course you wouldn't have an electron cloud; you'd instead have layers of less dense material surrounding the region that's actually at nuclear density.