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Black Hole Swallows Star
Thorfinn.au writes "The New Scientist writes a conjectural piece to explain the light pattern of SCP 06F6 in what was first identified as a supernova — but observations show a skewed and stretched light curve not fitting with an current theoretical explanation of exploding stars. Also, the discussion in the comments is interesting."
I'm not educated in astrophysics and everytime I read something like this I wonder, how does anything manage to get "blasted away" from a black hole? I was under the impression anything that got close to it was absorbed?
Simple, black holes are very messy eaters - they radiate a significant fraction of their food as photons. Keep in mind you are accelerating much of the star to a significant fraction of c, letting it collide with itself. This goes double for stellar mass black holes - you have a million+ kilometer star getting 'swallowed' by a twenty kilometer black hole. Even a perfect landing is going to result in most of the star's mass getting flung back out into space if only because the hole is smaller than the core of the star.
I am a science fantasy fan
Anything that crosses the event horizon is absorbed. Anything that does not interacts gravitationally with the black hole as it would with any other massive object. Black holes don't have any sort of magical ability to suck things in. All they have is gravity (Well, ok. They also have charge and spin.)
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
The common view that a black hole has a definite "boundary" beyond which nothing can escape, although essentially true, overlooks several important factors.
Yes, the "event horizon" (EH) is the boundary beyond which nothing can escape the gravitational pull of the black hole.
However, it's not a physical boundary (black holes do not have a physical surface), it's the mathematically-calculated boundary beyond which events inside the EH cannot affect an outside observer. As a particle gets closer to the EH, its chances of escape shrink to infinity, and once the EH is crossed, it's effectively gone from the outside world.
That being said, under certain conditions, particles can be radiated outward from a black hole:
1.) If an object inside the "photon sphere" (Schwartzchild Radius X 1.5) but still outside the EH emits photons, those photons can still escape. (Photons coming inbound are screwed, though. Approaching on a tangent, have a slim chance to "bounce off" due to rotational gain.).
2.) If the black hole is rotating, and a particle is approaching the black hole at a tangent, it may also escape via "stealing" some of the rotational energy.
3.) Rotating black holes also emit particles via Hawking radiation, which is more of a particle-antiparticle explanation that I want to get into here.
So, yeah, it's sort of an issue of semantics - if you consider the zone right outside the EH a part of the black hole, then yes, things can escape from a black hole; if you take the common (and incorrect) view that a black hole has a definite "border", and discount all the fun stuff that's going on around the black hole, then no, nothing can escape.
(Of course, this is a ridiculously simplified explanation, and I do expect at least one Slashdot astrophysicist to poke it full of holes (pun intended).)