Horrible Dangerous Things


It’s been hypothesized for a long time. Rogue black holes.

Nasa confirms that occasionally black holes get kicked out of the center of galaxies, and go zooming about. I think “zooming about” is probably not the technical term for what a supermassive black hole does, but it’s going to have to suffice.

A black hole 1 billion times the mass of our sun, zooming through space at 100,000 miles per second.

I don’t think even Bruce Willis and William Shatner, together, could do anything about that, except maybe gawp in awe.

The energy released from the collision of two supermassive black holes is on the order of a hundred million supernovas. I’m still curious what it would look like. We couldn’t see the black holes, but presumably they’d have accretion zones (in the case of a galactic center supermassive, the accretion disk is a galaxy, right?)  What would a human experience if they were, say, a light year from that incident? Obviously, there’s such a thing as a “safe distance” but what is it? Would gravity waves rip a human apart, or would we just bend with them and maybe feel something? What would we feel? What would we see? I like explosions, but the idea that there can be such a huge explosion that I can’t even see – for some reason that bugs the hell out of me.

Is this the biggest energy release that happens? I believe the previous biggest energy release was some supernovas apparently create enough of a shockwave that antimatter forms, then reacts with the matter that is present – sort of a pumped-up supernova. But this is clearly bigger. This is the Mother Of All Bombs.

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I know 100,000 miles/second means “too slow to get anywhere in the universe, really.” My little human brain can’t make any sense of these numbers. I don’t like the idea that there’s such an incredible explosion and my little human sensory apparatus can’t even appreciate it enough to be scared of it. Part of me is telling myself “this thing ought to be completely terrifying” and another part of me knows it’s giggle-worthy.

Occasionally, I notice that I am walking down a sidewalk and have just stepped on a bunch of ants. It reminds me that there are things out there that can step on us equally unknowingly. That doesn’t bother me because, at the scale at which I live, I can’t do anything about it, anyway. So: pizza for dinner tonight!

Comments

  1. CJO says

    As regards detecting the hypothesized gravity waves from such a collision, there are two laser interferometer arrays, one at Hanford, one in Louisiana. They’re c. 4 km on a side

  2. John Morales says

    Two holes in spacetime merge into one hole. A great deal of gravitational energy is radiated from their changed momentum, but that’s not visible — only its effects.

    There would be spectacular fireworks from the interaction of their accretion disks in the increased gravity gradient.

  3. Brian English says

    I don’t think even Bruce Willis and William Shatner, together, could do anything about that, except maybe gawp in awe.

    Clearly there would need to be a combination of those two, plus some of Steven Seagal, Chuck Norris, Jean Claude Van Dam, Arnold Swartznegger (sp?) to make it a fair fight.

  4. Holms says

    A black hole 1 billion times the mass of our sun, zooming through space at 1,300* miles per second.

    And if I’m being pedantic, that should be ‘1 thousand million’ rather than ‘t billion’.

    We couldn’t see the black holes, but presumably they’d have accretion zones (in the case of a galactic center supermassive, the accretion disk is a galaxy, right?)

    Perhaps in a kinda sorta poetic sense we could consider the galaxy at large the extended accretion disc, but more properly, no.

    And yes, black hole collisions are the single most energetic event detected to date. Possibly, it is the most energetic thing possible outside the original big bang. One hundred million supernovae… to put a single supernova into some semblence of perspective, I will direct you to xkcd.

  5. johnson catman says

    I know 100,000 miles/second means “too slow to get anywhere in the universe, really.”

    Sure, but it is still over half the speed of light, so it is moving pretty fast, especially for something so huge and potentially dangerous that we wouldn’t even see coming.

  6. NYC atheist says

    @6 holms
    Long billion system is dying in English, and long dead in American English.

  7. says

    John Morales@#4:
    There would be spectacular fireworks from the interaction of their accretion disks in the increased gravity gradient.

    I am picturing two gigantic circular saw blades made of dirt, fire, and dust, meeting edge-to-edge, at full speed. Silently.

  8. says

    Holm@#6:
    Perhaps in a kinda sorta poetic sense we could consider the galaxy at large the extended accretion disc, but more properly, no.

    Thanks for that; I’d wondered.

    One hundred million supernovae…

    9 orders of magnitude brighter than an H-bomb pressed against your eyeball? (NoooooooOOOOOO!!!!!)
    (and that’s just one of them)

    I didn’t assume that witnessing such a collision would be something anything would survive, unless it was very very far away.

    I still wonder what being ripped apart by gravity waves would feel like. Presumably there’d be some kind of massive existence failure when the waves strength got past the point the material we’re made of could distort to accomodate them.

  9. says

    johnson catman@#7:
    Sure, but it is still over half the speed of light, so it is moving pretty fast, especially for something so huge and potentially dangerous that we wouldn’t even see coming.

    Yeah, I wonder how far off it could be detected. I suppose the first indication that something was amiss would be when some of the Hubble’s guide stars started to appear to move. If my wildass guesses are right, it’d cover the distance between Jupiter and Earth in 10 minutes or so. The schwartzchild radius of Sagittarius A* is 41 light seconds (per wikipedia) and that’s about 1800 light seconds. So it wouldn’t gobble the whole solar system in one fell “schwoomp” but it’d be a mess. I know that the odds of anything hitting anything in space are fairly low; I assume a rogue black hole just zooms by in a straight line, shattering everything it goes anywhere near. ( <---- Note the use of "near", I do not know what "near" means when talking about supermassive black holes)

  10. Rob Grigjanis says

    Marcus @11: Your numbers are all over the place. The BH is moving at 1300 mps, not 100,000 mps, as Holms pointed out in #6. So it would cover the distance between Jupiter and Earth in days, not minutes.

    With a mass that large, even if it passed no closer than tens of thousands of AUs from the Sun, it would mess up the orbits of the outer planets at the least. That’s just a handwavy estimate based on Newton’s gravitation law (which is valid for distances much greater than the Schwarzschild radius and speeds much less than c). Much closer than that, and it’s curtains for the solar system.

  11. EnlightenmentLiberal says

    9 orders of magnitude brighter than an H-bomb pressed against your eyeball? (NoooooooOOOOOO!!!!!)

    I spot a xkcd reader.

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