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Black Hole Particle Jets Explained
Screaming Cactus writes "A team of researchers led by Boston University's Alan Marscher have apparently worked out the physics behind the particle streams emanating from many black holes. According to the researchers, 'twisted, coiled magnetic fields are propelling the material outward.' By watching an 'unprecedented view' of a black hole in the process of expelling mass, they were able to confirm their theory, predicting where and when bursts of energy would be detected."
Ok, so its juvenile and stupid. But it still made me laugh.
"Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
Note to all ID supporters, this is how real science works. Propose a theory which can be tested, then go about trying to disprove the theory.
Now go ahead, flame me. My karma can take it.
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This is a good article. It was complete enough to satisfy the casual interest of this old physicist who once worked for awhile as an astronomer, explained all of its terms in ways accessible to a more general public, but was never tedious about it. We need more science writing of that quality. Also good work, it would seem. Rarely do you get a chance to check astrophysical theory in such detail against observations.
Yes, this is completely different, but it's not exactly the black hole emitting anything. The jets are from material that hasn't fallen into the black hole yet, being accelerated along the axis of rotation by the twisted magnetic fields outside the black hole.
This is radiation from the accretion disk, which both supplies the material and twists up the fields which then accelerate the material. It's not from the hole itself. Of course it is all powered by the hole's gravitational field.
These particle jets aren't emitted from the actual "depths" of a black hole, but as the article says, ejected due to twisted magnetic fields perpendicular to its accretion disk. Once you get closer, space bends even the magnetic fields inwards, and everything else. And what goes that far is later emitted as Hawking radiation, the only form of energy theorized to be emitted from a black hole, in time believed to "evaporate" the black hole itself.
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That's what's left of the poor alien souls that attempted to use a pair of them for travel...
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Well, large black holes don't evaporate -- even the cosmic background radiation is enough to add more mass than they lose to Hawking radiation. The CMB is at ~2.7K, and a 1 solar mass black hole has a temperature of 60nK from the Hawking radiation.
From http://en.wikipedia.org/wiki/Birkeland_current "A Birkeland current generally refers to any electric current in a space plasma, but more specifically when charged particles in the current follow magnetic field lines (hence, Birkeland currents are also known as field-aligned currents). They are caused by the movement of a plasma perpendicular to a magnetic field. Birkeland currents often show filamentary, or twisted "rope-like" magnetic structure."
I wonder when they will discover that these "super massive destructive forces" are actually electric powerhouses that light up the cosmos.
It's both, they radiate very slow and the CMB will be warmer than them for a long time. I just looked it up, a stellar mass black hole will take 10^67 years to evaporate. I was way off when I said trillions. :)
The cool thing is, as they get smaller, they radiate faster. So they get smaller and hotter exponentially, and finally die (in theory...) in a massive burst of gamma rays. In the last second, they emit as much energy as a 5000000 megaton nuke. Would be a hell of a show (from a safe distance).
There's a black hole. Quantum vacuum fluctuations create a particle-antiparticle pair near it, both with positive mass. One falls in, the other escapes. Thanks to quantum weirdnesses, the mass for the escaping one gets stolen from the black hole. Half the time it will be the antiparticle escaping, and half the time the particle. (Overall, though, they'll mostly do the same thing and both fall toward it or away from it, and annihilate each other with no net effect. But on the rare occasion when they get created in the right spot with the right energy, one will fall in and the other will escape.)
Of course, you could just read the Wikipedia article.
If you have a spherical collection of particles randomly orbiting an object, collisions between particles tend to average out their angular momentum, eventually concentrating them into a thin disk. The oblateness of the rotating primary about which they orbit tends to force that ring into alignment with the primary's equator.
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Hawking radiation particles don't come from *inside* the black hole; that's impossible. Instead they are the "virtual particle" pairs that are constantly created (and almost always immediately destroyed) from vacuum fluctuations of the fabric of space time, specifically those pairs pop into existence straddling the infinitely thin line that is the event horizon. Due to gravitational acceleration, these particles become real due to the Unruh effect. If the antimatter particle, say an antiproton, is captured, it will remove mass from the black hole when it encounters a matter particle and releases energy. Coincidentally, the same amount of mass "radiated" is as the antiproton destroyed. Courtesy of the transitive property of addition, the net effect is the same as if the black hole had ejected one proton from within the event horizon.
khasim (12/9/06): In a blind taste test, more people preferred Coke over the Pepsi that I had previously pissed in.
Black hole translate to "trou noir", which is as funny (or unfunny) as "black hole" is in english. I don't ever recall an astrophysicists in France which was annoyed, or amused. I would REALLY like to see a reference to this.And to the moderator, such an assertion would require at least a lnik or reference to be modded informative +5. Right now at best it is only +5 funny.
C. Sagan : A demon haunted world:
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I've always wondered whether magnetic fields inside a black hole are restricted to being within the internal boundary of the black hole, but not able to penetrate outside it? Does the event horizon also apply to them? Does the boundary established by the hole's gravitational field prevent a magnetic field from emerging? That would imply gravity can trump magnetism. I guess that makes sense if gravity warps space, and magnetism has to propagate through space, so if space is distorted the magnetic field lines are too. So does this mean one could somehow bottle up enormous magnetic fields within a gravity-compressed space? Does this operate in suns to contain their reactions? And why do my friends from Tau Ceti always look at me like I was crazy when I ask them this? Just because I'm human doesn't mean they have to treat me like a galactic retard. Although that explains the Slinky they gave me, claiming it was advanced alien technology.