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.

Comments

Protect yourself

[Beavertank]

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.

Eye muss bee knew hear

[sm62704]

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)

Re:Eye muss bee knew hear

[Dan East]

"The way the black hole could turn into a quasar is for the galaxy to collide with another galaxy."

That's not what the article says:
It's not understood what is causing the black holes to become newly active, because in most cases there is no evidence of collisions or mergers.

Re:Eye muss bee knew hear

[DirkGently]

Because black holes can only "eat" so fast.

As matter accelerates and gets closer and closer to the event horizon, particles begin bouncing into each other, like outside that one Who concert. Except in this case, instead of being crushed to death (as those concert-goers), centripetal force slings matter towards the poles of the hole with enough energy to achieve escape velocity. This creates a massive beam of ultra-high energy particles that would be very bad for your health. Well, two beams (one "up" and one "down"), but you get the idea.

Re:Eye muss bee knew hear

[IndustrialComplex]

Massive relativistic death lasers? Concertgoers bouncing against each other to near the speed of light?

It isn't a galactic collision. It's just the reunion tour for Disaster Area.

20 to 40%? Reignite?

[Gat0r30y]

From TFA it seems like somewhere between 20-40% of galaxies surveyed have active nuclei, but how do they know they reignited?

It's not understood what is causing the black holes to become newly active, because in most cases there is no evidence of collisions or mergers. How could it be verified that despite the lack of a recent collision with another galaxy, these particular phenomenon were at some point dormant like ours, then reignited? How are they supporting this claim that these galactic nuclei must have spontaneously rekindled vs. they have been winding down from a collision very far in the past?

There's just one problem: Astronomers have found quasarlike centers--called active galactic nuclei (AGN)--in some relatively nearby galaxies, which should be far too old to generate such energies. So they should be too old for this sort of behavior, but how are they verifying the time since the last collision? Another possibility is that these galaxies had a collision more recently right?

The galactic core could be exploding?

[meringuoid]

... 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.

No evidence for "re-ignition"

[random coward]

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.

Re:oblig.

[infonography]

Worst. Trek. Movie. Ever. Don't be so hasty, there are plans for many more....