Black Hole Emits a 1,000-Light-Year-Wide Gas Bubble 145
PhrostyMcByte writes "12 million light-years away, in the outer spiral of galaxy NGC 7793, a bubble of hot gas approximately 1,000 light-years in diameter can be found shooting out of a black hole — one of the most powerful jets of energy ever seen. (Abstract available at Nature.) The bubble has been growing for approximately 200,000 years, and is expanding at around 1,000,000 kilometers per hour."
very minor issue (Score:5, Informative)
Re:How can a black hole emit anything? (Score:5, Informative)
The phraseology in the article is misleading. The energy and gas jets are emitted as matter falls towards the black hole and becomes superheated from the falling. Once the matter crosses the boundary ( event horizon ) into the back hole itself it disappears from the rest of the universe.
Information is released, but very very slowly.
Re:How can a black hole emit anything? (Score:5, Informative)
They can emit Hawking radiation.
Basically, pairs of particles appear out of nowhere for extremely brief amounts of time, fly around a bit, then collide together and disappear again.
(Yes, this happens. Matter appears out of nowhere and then disappears again.)
If this pair of particles pops into existence just outside the event horizon of a black hole, there's a chance that, in their brief flying about, one will cross the event horizon and the other will not. Since they're no disjoint, they don't disappear like they normally do.
The particle that is on the outside of the event horizon escapes as Hawking radiation.
End of the world. (Score:4, Informative)
Let's do this grade 6 math puzzle style.
Expanding at ~1,000,000 km/h
12 million light years away.
It already has a radius of 1000 light years.
Assume a light year is 9.46 trillion km long.
Assuming this gas bubble was created by the universes first perpetual motion machine, so the growth is constant, how long before this gas bubble wipes out all life on Earth. Someone watch my math and make sure I didn't slip up.
(9,460,000,000 * 12) - 5000 = 113519995000 km to go.
113519995000 * 1000 = 113519995000000 hours left.
Or 4729999791666.6 repeating days
Or ~675714255952 weeks
or ~12994504922 years.
If we do live forever, mark your calendars, 12994506932, Earth is finished.
pictures are here (Score:5, Informative)
Re:Third grade truism (Score:4, Informative)
smell is chemical. therefore it's based on the interaction of electron clouds around atoms in particular configurations within molecules. therefore it acts by means of the electromagnetic force. therefore it's mediated by virtual photons. virtual photons are light. light can go only one direction in a black hole, and that's down. so the black hole can't smell it because the virtual photons of its nose can't interact with the virtual photons of the gas outside the black hole to indicate that there are electrons, atoms, and molecules there.
so there, smartypants.
Re:Imagery (Score:5, Informative)
That's a piss-poor artist's rendition that on the one hand has a silly sun being slurped up like spaghetti by a black hole, and on the other hand has a depiction of the sort of jet that actually occurs at the poles of a spinning black hole.
The actual "bubble" is diffusion of the jet into gas somewhere off in the direction of the black hole, and is not depicted in that image.
Re:How can a black hole emit anything? (Score:4, Informative)
An inner and outer event horizon? last I checked the event horizon was the point at which nothing not even light escapes. By that definition theres only one event horizon. If something goes in and is able to come out, it obviously hasn't entered the event horizon. I assume what you are talking about is the gravitational swing effect by which an object enters the gravitational field long enough to gain speed before it is slingshots away before being sucked in.
I think he's talking about the ergosphere [wikipedia.org].
jdb2
Re:How can a black hole emit anything? (Score:5, Informative)
The dominant theoretical model of black holes has them emitting energy (Hawking radiation).
Though I don't think the effect here is really the black hole emitting anything (from within the event horizon), but an instead an effect that occurs because of gravitational compression outside the event horizon.
Re:How can a black hole emit anything? (Score:5, Informative)
In science, its important to remember that a "theory" is not the same thing as the loose definition of a theory in casual conversation, or some technical but non-scientific contexts (literary criticism, I'm looking at you.)
In science, a theory is a hypothesis whose predictions which make it falsifiable have withstood testing and which remains viable. The casual-conversation concept of "theory" as an plausible but unverified idea about the world is what in science would be a conjecture or a hypothesis, not a theory.
So, often, we talk about theories (as opposed to mere conjectures or hypotheses) as if they were known except in very particular contexts where there theoretical nature is particularly important (such as in the case of a conflict between two theories that have both withstood scrutiny but where the predictions each makes in conditions impractical to test conflict.) But there's a good reason for that: if it is a "theory" as the term is used in science, it has demonstrated it power in explaining behavior beyond that which was consulted to formulate it. It may need to be refined, but its known to be a useful model.
Re:How can a black hole emit anything? (Score:3, Informative)
No, antimatter does not have antimass. And it is 50/50 as to which of the pair falls into the black hole. But for that formerly virtual particle to now exist as a "regular" particle it's energy has to come from somewhere, and in this case, "somewhere" is the black hole. I believe that this is one of those points where to go further, you need to get into the actual math.
Re:How can a black hole emit anything? (Score:4, Informative)
I would like to add that this kind of Hawking radiation is extremely slow process and that it has nothing to do with giant fireballs escaping from black holes as such. Or, very probably, anything else we can detect.
Re:How can a black hole emit anything? (Score:4, Informative)
Several other comments talk about a pair of particles being created out of nothing, one gets absorbed and the other flies away. This is basically right, but can be confusing (the one that gets absorbed has negative energy in order to conserve energy). Here's an easier mental model....
Steve Hawking came up with an idea a while ago (70's perhaps?). He was thinking about black holes whose event horizon was around the size of an atom. Then he put it up against the Heizenberg Uncertainty Principle. He realized that particles in these black holes would have such a high degree of certainty about their position, that there would be such a low certainty about their velocity. Therefor, there would be some that would be REALLY fast. Not fast enough that they could escape the pull of the black hole, but fast enough that they could get just above the event horizon. There, they could give off a high-energy photon, and fall back in. This photon, since it was emitted outside the event horizon, would actually escape. This radiation can (and has been) detected, and causes what is known as evaporation. http://en.wikipedia.org/wiki/Hawking_radiation#Black_hole_evaporation [wikipedia.org]
Ironically, this means that smaller black holes (which have higher certainty about a particle's position) evaporate faster. Large-ish black holes absorb more energy cosmic microwave radiation than they emit in Hawking radiation, but if they have small enough mass (I believe smaller than the size of our moon), they emit more Hawking radiation than they receive from the cosmic background.