[HN Gopher] Hubble captures a black hole that is forming stars, ...
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Hubble captures a black hole that is forming stars, not absorbing
them
Author : gmays
Score : 92 points
Date : 2022-01-21 18:11 UTC (4 hours ago)
(HTM) web link (petapixel.com)
(TXT) w3m dump (petapixel.com)
| Shadonototra wrote:
| so black holes basically mix all the space dust together,
| condensate everything, let it sit like a dough, and then comes a
| fresh star? the life cycle of the universe!
| staticassertion wrote:
| Except for the shit that falls into it. All of that mixing is
| happening outside of the event horizon.
| malfist wrote:
| No, this headline is very misleading. Blackholes eat everything
| that crosses the event horizon and nothing* ever escapes from
| that. But lots of thing near the black hole don't get sucked
| straight down.
|
| Everything a blackhole pulls on already has momentum on it's
| own, so the black hole's tug causes it to spin around the
| blackhole. Angular momentum is conserved, so what happens to
| most matter is that the blackhole grabs it, and slings it hard
| in another direction, very little actually "falls" in. The
| stuff it slings out tends to move in similar directions, and
| that can cause things to clump together and form stars.
|
| Additionally, all the spinning around the blackhole generates
| heat and radiation, this gets ejected in massive bursts coming
| out of the rotational axis of the black hole. This stream of
| energy can hit other dust, heating it up and causing it to
| condense. This can lead to a birth of a star.
|
| It's long been thought that blackholes can form stars through
| those methods, but this is the first time it's been observed.
| Not groundbreaking, but does confirm a theory.
|
| *: offer does not apply to hawking radiation
| belval wrote:
| I know next to nothing on black holes/star formation and
| astronomy in general, but isn't this a big deal? I thought a
| pretty big defining factor of black holes was that nothing (not
| even light!) ever escaped it?
| uoaei wrote:
| It is definitely an unusual observation, but I don't think it's
| really that big of a deal. A strong gravitational field would
| pull matter closer together, possibly kick-starting the fusion
| process if the energy density gets high enough in a certain
| region. If you asked an astrophysicist what would happen to a
| massive dust and gas cloud near a black hole, star formation
| would be 2 or 3 on the list that they rattle off.
|
| > But the gentler outflow of gas from the black hole in Henize
| 2-10 is compressed just enough to facilitate star formation.
|
| It's a Goldilocks thing. Black hole is strong enough to have a
| significant gravity, but weak enough that the shell of hot
| dense matter it harbors doesn't completely obliterate
| everything that falls toward it.
| kadoban wrote:
| This is not evidence that anything has escaped the event
| horizon of a black hole. That _would_ be huge news (also pretty
| ~impossible, but still).
|
| This is just the region _near_ a black hole doing some star
| formation. Which is cool, but also :shrug:.
| jvanderbot wrote:
| You can orbit a black hole like any other object, and most
| things do, for a _long, long_ time. Hell, the whole milky way
| is basically orbiting a black hole (and a lot of other mass
| near the center).
| ben_w wrote:
| And some of the stars close to the Milky Way's have completed
| entire orbits on camera:
| https://www.eso.org/public/videos/eso1825e/
| thehappypm wrote:
| I recently learned about delta-V as a concept. Flying
| directly into the sun, for example, is basically not possible
| for a spacecraft with today's technology, without dozens of
| gravity boosts. You need to basically undo the speed of your
| initial orbit, which for something in orbit around a star is
| huge!
|
| A black hole would be even more difficult and require more
| Delta-V to fly into, if you're in any sort of orbit. So you
| should definitely expect tons of stuff in orbit around them!
| acomjean wrote:
| So all matter is doomed to get sucked into one of these
| things eventually?
| fennecfoxen wrote:
| And orbiting a black hole is just like orbiting any other
| object, except the surface is much closer to the center of
| mass.
| davesque wrote:
| I don't think this finding challenges any of those assumptions.
| I think the explanation was that the relativistic jet for
| smaller blackholes located at galaxy centers is moving slow
| enough that the compressive effects of the jet are not overcome
| by the speed. The compression therefore helps with star
| formation since the jet isn't moving fast enough to disrupt
| that process.
| tejtm wrote:
| Might help to think of it as more of a reprieve. In that the
| star itself or its remains will still likely end up inside the
| black holes Schwarzschild radius never to be seen again except
| as Hawking radiation till the BH evaporates.
|
| That the environment directly outside a BH is energetic enough
| fling some stuff "up" does not mean the stuff can't/won't fall
| back "down".
|
| In this case the stuff flung "up" happens to have the necessary
| properties to _trigger_ star formation further away, which is
| mostly an incoming shock wave and an preexisting cloud of
| "cold" stuff.
|
| The stuff the BH is throwing in its shock wave is _not_ going
| to be "cold". So to facilitate star formation the shock wave
| has to be less hot / less dense than and maybe slower than a
| larger BH hole would produce (which would more typically shred
| the cold cloud to tatters instead of causing it to collapse in
| on itself precipitating a star)
| pdonis wrote:
| _> the star itself or its remains will still likely end up
| inside the black hole_
|
| Not necessarily. Black holes don't have any more tendency to
| "suck things in" from a distance than any other object with
| the same mass.
| tejtm wrote:
| space is pretty big, but I would bet eternity wins this
| one.
| jonshariat wrote:
| As a layperson, I always wondered this about gravity.
| Does it attract over infinite distance or does it have a
| range?
| karmakaze wrote:
| Thinking in continuous terms, it would be infinite and
| inversely proportional to distance squared. But thinking
| in terms of a distortion in space-time and also
| considering that it may be quantized, perhaps there is
| some limit. Also for points that are separating faster
| than the speed of light due to inflation gravity couldn't
| alter that space.
| pdonis wrote:
| _> I thought a pretty big defining factor of black holes was
| that nothing (not even light!) ever escaped it?_
|
| Nothing ever escapes from _inside_ the hole 's horizon. But
| there can still be a lot of interesting things happening
| _outside_ the hole 's horizon as matter either falls in, or
| orbits the hole, or some combination of the two; and we can
| certainly observe things happening outside the hole. That has
| been known for decades.
| amelius wrote:
| The laws of physics are time-reversible, after all.
| ldoughty wrote:
| Felt mildly like a clickbait title (in my opinion)
|
| It still absorbs stars... and other matter... lots of it...
|
| but those somewhat more familiar with black holes know not
| everything is sucked in... black holes (commonly? -- I never
| looked into prevalence of this) have "jets" that push material
| away, often at high speed.
|
| The "revelation" of this article is that we have the first
| photographic evidence supporting the fact these "jets" can
| contribute to the creation of stars.
| pdonis wrote:
| _> black holes (commonly? -- I never looked into prevalence of
| this) have "jets" that push material away, often at high
| speed._
|
| This is quite common. The jets are present in most black holes
| that are rotating with significant angular momentum compared to
| their mass, which is, AFAIK, a substantial majority of all
| black holes that have been observed.
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(page generated 2022-01-21 23:00 UTC)