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Why Some Supermassive Black Holes Have Big Jets
astroengine writes "Some of the supermassive black holes at the centers of galaxies have powerful jets blasting from their poles, and others have weak jets, but many don't have jets at all. Why is this the case? In new simulations carried out by astronomers at NASA and MIT, it would appear that the way in which the black hole spins relative to its accretion disk may be a contributing factor. Strangely enough, the results indicate that if the black hole rotates in the opposite direction to its accretion disk, the most powerful jets form. The region between the black hole event horizon and the accretion disk still baffles scientists, so these simulations are very speculative, but the results seem to match what radio astronomers are seeing in the cores of active galaxies. Perhaps it's time to fire up that event horizon telescope!"
I was completely sucked in.
Is there a name for the theory that matter is being sucked out of our universe as fuel for another?
Kind of hard to reconcile since black holes increase in mass as they draw in matter (aka mass.)
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
They also decrease in mass by emitting hawking radiation.
http://en.wikipedia.org/wiki/Hawking_radiation
MACHO: Massive compact halo object
An alternate theory is WIMP. You can imagine which ones the nerds prefer.
the growth in cynicism and rebellion has not been without cause
They increase in mass, yes but does their size increase? Where does the matter go if it's all compressed to a singularity? Are all the atoms just spaghettified, stacked one on top of the other in some infinitely tall, infinitely narrow well?
I have only a most basic grasp of cosmology but it's an interest of mine and I recall watching something on documentary heaven to the effect that black holes may well be a universe of their own. To be honest the very idea of a singularity still baffles me: it seems as though you start with an assemblage of simple, dull matter and in the blink of an eye any semblence to matter as we know it disappears and you're left with something that - to me at least - sounds like a feature of space itself.
Exactly what happens between the instant when you have a very, very dense lump of matter and an infinitely dense one? It seems an infantile question but where did all the matter go? Or was it transformed into something else that has mass but no size? Thinking about it gives me a headache and usually leaves me pondering whether any particles really have a physical size or if it's just another consequence of our limited view of the Universe.
If God forks the Universe every time you roll a die, he'd better have a damned good memory.
Some of the supermassive black holes at the centers of galaxies have powerful jets blasting from their poles, and others have weak jets, but many don't have jets at all.
Some black holes are in a bigger hurry than others, hence bigger jets. While the ones that don't have jets are more concerned about the environment and galactic warming so they use public transportation.
Actually, math only breaks down at the Event Horizon, and physicists pretty much ignore that one point and continue on. Theoretically, due to all calculations, time at the singularity proceeds just like it does for a non-relativistic observer. And you can in fact, calculate the amount of time it would take for you to reach the center of the black hole, though somebody watching you would say it took an infinite amount of time since they see you as stopping at the Event Horizon. But to you, you actually reach the Singularity.
You may be thinking of the 'White Hole' theory.
http://curious.astro.cornell.edu/question.php?number=108
http://en.wikipedia.org/wiki/White_hole
I have only a most basic grasp of cosmology but it's an interest of mine and I recall watching something on documentary heaven to the effect that black holes may well be a universe of their own
One of my most favorite books on the subject is called The Five Ages of the Universe by Adams and Laughlin. If you like reading books about the subject but don't care about or can't comprehend the math, I seriously recommend it. That said (and I think it's in the book I linked), there's an evolutionary theory about universes that contends each time a black hole is created, it splits off a unique instance of spacetime creating a "new" universe with its own laws of physics. Universes created in this manner that contain laws of physics favorable to the creation of black holes will go on to evolve new "child universes" of their own; a sort of cosmic equivalent of Darwin's natural selection.
;)
One more thing, should you find yourself occasionally staring at the TV and wanting to feel educated and entertained, then you should, uh, "acquire" a copy of Into the Universe with Stephen Hawking. It's a very well written and well narrated version of how Hawking explains the workings of the universe, but unfortunately isn't available on DVD yet. However, the trusty folks on the web that don't make any money from TV and movie distribution should have a copy you can pick up today
The extremely fun thing about physics from a layman's point of view is that there are so many theories about how the same things work, and getting them presented to you in a manner you can understand without knowing the math behind it is a wonderful thing. From there, you can theorize and come to your own conclusions about which you like best, because if Planck has anything to say about it, we'll never truly know which of them is right.
It's kind of like going to a trade show, only instead of the place being full of vendors, it's full of missionaries from every major religion on the planet, and you get to objectively pick the one you like the best. I'm sure most Slashdotters would be drinking the free coffee at the Atheists' booth or ignoring everyone and speculating what the giant bundle of Cat5 on the wall goes to, but regardless of whether your God is supernatural or nonexistant, to glimpse into the very fabric and inner workings of the cosmos is the only true way to see into that mind.
Still, even if that's not the way you see it, I do feel that it's also the only way to even begin to fathom what we all really are.
Boot Windows, Linux, and ESX over the network for free.
Yes, there is a direct relationship between the radius of the event horizon and the mass-energy within the event horizon. More massive or more energetic black holes have broader event horizons. This is observer dependent and subject to a Lorentz contraction, so if you are accelerating directly towards a black hole it will appear more massive (and thus have a larger radius) than if you are accelerating directly away from the same black hole; this effect increases exponentially as (absolute) relative velocity increases towards c.
When any observer sees mass-energy crossing into the event horizon, the event horizon's radius increases proportionately. Again an observer's measurement of that mass-energy is subject to a Lorentz contraction.
There is also an inverse relationship between the surface area of the black hole and its temperature; both are subject to the same Lorentz contraction, but more massive black holes emit photons similarly to colder blackbody radiators than less massive black holes.
We have no useful theory about what's going on the inside of an event horizon.
There are several ways to consider the microscopic states inside a black hole from a thermodynamics-meets-General-Relativity perspective. Here's one. In GR (and we have tested this), the lower the gravitational potential in which a clock is, the slower it ticks, for any form of clock (including naturally oscillating processes). Ignoring observers experiencing acceleration other than via gravitation, the gravitational potential is very high in inter-galactic-cluster space (i.e., farrrr away from dense mass-energy), lower inside solar systems, lower still on planetary surfaces, very low inside stars, and extremely low inside black holes. Consequently, a "clock" ticking inside a black hole will, from the perspective of someone with a high gravitational potential, tick very slowly. The "clock" itself, however, will always tick at its natural rate, from its perspective and the perspective of anything immediately near by it, unmoving, and at the same gravitational potential.
So from our perspective on Earth, a natural oscillator inside an event horizon will go from oscillating at, say, several GHz, to oscillating less than once every several billion years of our time.
From its perspective our clocks on Earth will speed up by the same factor.
However, where things get strange is where the gravitational potential changes in distances shorter than the wavelengths of protons, neutrons, electrons, photons, and so forth, since they are ultimately oscillating "clocks". If "part" of a proton is in a higher gravitational potential than the rest of it, how do the quarks and gluons within it behave? What happens to the proton? And so forth.
That requires a consistent unified theory of gravitation and quantum mechanics, which nobody has been able to demonstrate yet.
Electrons, Protons, and Neutrons obey Fermi-Dirac statistics for fermions. Spatially, this means that you can't stack them all in one place - there is a pressure separating fermions from one another. When you introduce pressure from, for example, gravitation in a heavy star, it overwhelms the fermionic pressure and creates "degenerate matter". Neutron stars have degenerate phases including neutrons formed by squashing together electrons and protons. Quark stars may exist, and would have degenerate phases formed by squashing together heavy (i.e., full of neutrons) atomic nuclei. Pressures at and inside an event horizon would almost certainly lead to some further degenerate phase, and we have no idea what happens then.
(We can somewhat reproduce some