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Milky Way Black Hole Could Reignite
sciencehabit sends us to Sciencemag.org for an account of a survey of nearby galaxies that points to the possibility that once-quiescent galactic nuclei could wake up and become active again. If the Milky Way's dormant black hole should become active, it could be bad news for life on Earth (and elsewhere in the neighborhood). The paper (PDF) is up on the arXiv.
Remember kids, just like government mind control rays the gamma ray bursts generated by our galaxy's black hole center can be blocked by a tin foil hat.
You may want a tin foil codpiece, too.
What does.. God.. need.. with a starship?
Slashdot Burying Stories About Slashdot Media Owned
Darn, and I never EVER rtfa, but the summary made it necessary. So for my fellow slashdotters who hate to RTFA, what they mean by "reignite" is to turn into a quasar. The way the black hole could turn into a quasar is for the galaxy to collide with another galaxy.
I don't think we have anything to worry about. Nothing to see here (and if it happened, nobody to see it)
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
So massive core explosions delivering a huge radiation wave are expected.
Step 1:
- invent scrith
Step 2:
- build Ringworld
Step 3:
- profit (sell real estate)
SO - not unlike the assertion (for example) that there's a large asteroid with Earth's name on it, this research seems to indicate that perhaps we should start studying this phenomenon now even if there's nothing we can do about it now. After all, much of our modern technology was understood to be impossible/impractical as little as a century ago; if we start looking now, perhaps we can devise a mechanism for the preservation of our species before we need it. Then again, when has humanity ever shown that much foresight?
Prediction: The real iPhone killer is going to be sex robots from Japan. Think about it.
... Well, shit. I'd nearly saved up enough to buy a General Products hull, and now it seems they've shut up shop and left town.
Real Daleks don't climb stairs - they level the building.
Its 30K light yers away, so we wouldnt know for that long.
Quick summary of TFA: Scientists observe that the black holes at the center of galaxies were Quasars on far away galaxies. The one at the center of the Milky Way and other nerby galaxies were observed to not be Quasars. So they theorised that the black holes initially are quasars after galaxy formation, and they run out of fuel. New observations show that nearby galaxies do in fact have quasars. A scientist conjectured that it re-ignited. Better conjecture may be that the fuel source of those blackhole-quasars is more variable than previously thought.
Don't active galactic nuclei fire out their "death rays" along the axis of rotation, ie perpedicular to the galactic disc, where we are.
OK, here's my theory:
We detect the presence of black holes at galactic centers by observing the stars whirling around said galactic center at high rates of speed, right? All those stars whirling around have mass, therefore, gravity. Other stars moving around, maybe not as near to the galactic center, also have gravity. All this movement and such may attract, due to gravitational pull, a cloud of gas somewhere nearby. Slowly it gets pulled by the stars' gravity, until it gets into the gravitational pull of the black hole. Quasar'd!
There are only 10 kinds of people in this world... those who understand binary and those who don't
You DO know that such collisions involve one particle with high velocity impacting a particle at rest (relatively speaking) with respect to the earth, making the collision products scatter like billiard balls after a good break and thus taking them away from the planet in short order? As opposed to colliding two streams with opposite and equal momentums, creating whatever they create at rest (relatively speaking) with respect to the earth?
Am I expecting the earth to get eaten up by strangelets or mini black holes? No. But the "oh, hush, collisions like this happen all the time" apology has a big leak in it that I haven't yet heard addressed. If evil bits get created in natural collisions, they go scooting off into space at high velocities before they have a chance to do damage here; while if evil bits where to get created in the LHC, they'd have little momentum and would hang around.
So how many orders of magnitude smarter than the guys who told us that the Space Shuttle would was safe to one mission in 100,000, are the guys telling us this is perfectly safe?
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
For a black hole to be active, it needs stuff falling into it...gas, dust, stars if you're unlucky. The stuff heats up to an extraordinary temperature due to friction as it falls in. To be hazardous at our distance of 25,000 light-years from the galactic center, it has to be quite a bit of matter falling in for a harmful intensity of radiation.
Our galaxy's black hole, Sagittarius-A, is not considered active, although it does have some weak emissions, primarily at harmless infrared and radio wavelengths consistent with a very small accretion disc. The nearest star to the black hole is estimated to be about 70 times as far away from it as it would need to be for the gravitational forces to remove significant amounts of material from the star. It also has an orbital period of 15 years, so it would take a long time and a significant perturbance to fall significantly close. It doesn't seem likely at all that it would become active in the foreseeable future.
http://en.wikipedia.org/wiki/Quasar
Quasars are an effect created by the supermassive black holes at the centre of each galaxy, these black holes consume tremendous amounts of mater (something like 10 sun masses a year) the more solar masses they consume the brighter they are. Obviously there is only so much material than can be pulled in by the supermassive black hole, eventually all the material is either ejected as high intensity engery (the quaser pulses we can observe) or consumed by the black hole.
The article mentions that astronomers have discovered galaxies with quasars which are old enough that the matter orbiting the black hole should have been used up. The current scientific hypothisis for old galaxies with quasars, is that the collision of two galaxies can generate new material which is pulled in by the supermassive black hole (thus supplying the matter to generate a quasar.) These older galaxies don't show any signs of recent collision and so the question of how the black holes in the centre are getting enough matter to generate a quasar needs to be asked. Since scientists don't know why there are quasars on these older galaxies they seem to be assuming that something else is causing new matter to be sucked into a galaxies supermassive black hole. The articles twist is this could potentially happen in our own galaxy, potentially killing us all.
It seems to me that a significant fraction of the collisions would produce particle showers pointed towards the ground. Even if 99% of the "evil bits" have momenta that don't allow them to settle into the earth, there's still a lot of evil bits (produced by incident particles with energies 10^4-10^6 times more energy than the LHC) over the last 4+ billion years that haven't destroyed the earth.
Of course maybe I'm missing some fundamental point here, and there's a reason to view this as a "giant hole" in the theory. If someone could be so kind as to point it out I'd appreciate it.
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