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Milky Way Black Hole Could Reignite

Posted by kdawson on from the tinfoil-umbrellas-might-help dept.

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.

5 of 117 comments (clear)

  1. Eye muss bee knew hear by sm62704 · · Score: 4, Informative

    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
    1. Re:Eye muss bee knew hear by Dan+East · · Score: 5, Informative

      "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.

      --
      Better known as 318230.
  2. No evidence for "re-ignition" by random+coward · · Score: 4, Informative

    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.

  3. Re:20 to 40%? Reignite? by HTH+NE1 · · Score: 3, Informative

    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? By the velocity vectors of surrounding matter affected by the blast? A collision would give the local matter directionality whereas a spontaneous reignition would send matter out in all directions uniformly.

    Haven't you watched CSI: Stellar Cartography Unit?
    --
    Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
  4. Feed Me by iamlucky13 · · Score: 3, Informative

    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.