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A Naked Black Hole Is Screaming Through the Universe (gizmodo.com)
New submitter PongoX11 writes: Millions of years ago, B3 1715+425 was just an ordinary supermassive black hole. It had a comfortable life, of devouring stars and belching deadly x-rays, at the center of its distant galaxy. Now, starless and alone, it's screaming through space at 2,000 kilometers per second -- and it may never stop. BC 1715+425's troubles began when its galaxy bumped up against another. This isn't all that unusual: in fact, astronomers believe that the largest galaxies in our universe formed during ancient mergers. Normally, when two galaxies collide, the supermassive black holes at their centers start to orbit one another, moving closer and closer together in an inescapable gravitational attraction. Eventually, those black holes can fuse, releasing a burst of energy as gravitational waves and completing the cosmic joining. Most of the time, this process seems to work out for all parties involved, judging from the fact that nearly all supermassive black holes reside at the center of galaxies, and nearly all galactic centers contain a supermassive black hole. But every now and then, something goes wrong and cosmic wreckage ensues. B3 1715+425, speeding away from the core of a bloated galactic merger 2 billion light years from Earth, is living proof of this. The working theory is that millions of years ago, B3 1715+425's galaxy passed through a much larger galaxy (one that had formed during many previous mergers) and got shredded to bits, a bit like a paper airplane flying into a hurricane. The leftovers include a faint galactic remnant, just 3,000 light years across, and the supermassive black hole itself, nearly naked and hemorrhaging ionized gas as it tears through the void. "We were looking for orbiting pairs of supermassive black holes, with one offset from the center of a galaxy, as telltale evidence of a previous galaxy merger," said James Condon, the astronomer at the National Radio Astronomy Observatory who led the study. "Instead, we found this black hole fleeing from the larger galaxy and leaving a trail of debris behind it."
Why is it the heavier they are the more they like running around naked?
How do you know that? Their relative velocity would depend on how fast the galaxies were moving together, and the escape velocities would depend on how close they passed by one another.
Sheesh, evil *and* a jerk. -- Jade
By definition, objects a long distance from each other are outside each other's escape velocity. Earth and Mars, for example would never go into orbit around each other without the influence of a larger object like Jupiter or the sun. This is the starting condition for the two black holes.
http://michaelsmith.id.au
Indeed if two black holes started very far away from each other and never passed so close to each other that newtonian approximation breaks down _and_ in empty space this would be true. However they are not in empty space but pass thru both galaxies flinging stars to very energetic orbits as they go. This is called dynamical friction and is usually enough to bind the two black holes.
Normally, when two galaxies collide, the supermassive black holes at their centers start to orbit one another, moving closer and closer together in an inescapable gravitational attraction.
That's how I met my girlfriend.
If you want news from today, you have to come back tomorrow.
Screaming through the universe?
In space no one can hear you scream.
"By definition, objects a long distance from each other are outside each other's escape velocity"
Excellent. So we don't need to worry about the Death Asteroid.
Whatever information escapes from the naked screaming black hole, is Too Much Information.
The collision must have happened more than 2 billion years ago, or we wouldn't know about it yet.
Speaking of galactic collisions, theres a new eBook out from Ian Douglas called Altered Starscape
(Ian Douglas is the author of the Star Carrier series and also writes under his real name of William H Keith)
This new series is called "Andromeda Dark" so its probably not much of a spoiler to tell you that the other galaxy involved is M31
Highly recommended for fans of Space Fleet / Galactic Empire science fiction
I would have thought "A Naked Black Hole Is STREAKING Through the Universe" would have been the obvious headline.
On the other hand I grew up in the 60's-70's...
The title of this post is annoying. As is usually the case these days, of course.
But in this case it's particularly annoying since it "hints" at this being at least related to a naked singularity. Something which would be very interesting indeed.
And "screaming"? At 2000 km/s? No.
Bad Slashdot.
The black hole isn't screaming, it's the victims.
"Wait. Something's happening. It's opening up! My God, it's full of apricots!"
s/Screaming/Streaking/
A Naked Black Hole Is Streaking Through the Universe
There, that's better.
Specialist Mac support for creative pros, Melbourne
what does escape speed (direction of the velocity vector is irrelevant for the "escape" condition to apply, unless the direction would result in a collision) matter to a "death asteroid"? It can still hit us moving over escape speed....
"I do not agree with what you say, but I will defend to the death your right to say it"
It's still quite interesting that the black hole got accelerated to such a speed, and only reason I can see for it is that it had a near miss with another much heavier black hole.
Imagine the bang when it finally hits something heavier than itself.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
It depends on their relative speed if they would get into orbit of each other - low relative speed and no other significant mass nearby disturbing the balance and you would get them to act as a pair of dancers rotating around each other - even if it's going to be slow it would happen.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
we found this black hole fleeing from the larger galaxy and leaving a trail of debris behind it.
Sounds like a standard relationship breakup to me...
Would this produce any gravity waves that we can detect?
No this would not be possible with 2016 technology already built and running. It would produce extremely faint waves each time the black holes moved by each other. Likely this happened because this hole was significantly less massive than the other black hole and got a lucky slingshot style flyby when they came near much like spacecraft use today to increase thier speed.
Gravitational waves are so difficult to detect it is only in the final interaction where they are orbiting eachother many times a second very close together and pump more energy into a burst of gravity waves than the continuous luminous output of whole galaxies that we can detect today.
This thing is not completely 'naked', it can still be detected via this gas cloud that surrounds it and if something like this object (not necessarily supermassive) was headed our way, it would presumably be detectable long before it arrived. A completely naked black hole would be essentially undetectable until it was pretty close to our solar system... or wouldn't it. Anyway, this got me thinking about how likely it is that a black hole hurtling through space would be completely 'naked' i.e. completely invisible?
In astronomy, you can see things scream instead.
Ezekiel 23:20
Um, a naked black hole is actually a very specific thing (a singularity without an event horizon) that may or may not even exist in nature. Just skimming the article, this sounds like an ordinary black hole to me.
Just a regular, hairless yet non-naked black hole. That's what it sounds like.
It's the same situation with asteroids and ice comets colliding. A head on collision would be an instant joining. A head-on near miss and they just carry on in slightly modified orbits. If the collision happens because rhe one behind is moving faster than the one in front then the relative speed is the difference in velocities. That allows everything to happen slowly.
When I first saw the headline, I thought they were talking about a Naked Singularity. Now that would have been interesting.
When I first saw the headline, I thought they were talking about a Naked Singularity. Now that would have been interesting.
That's what I thought too.
Me too. I was intensely excited for several seconds.
B) Eliminate all the stupid users. This is frowned upon by society.
Hahahahahahahaa! Nice one.
B) Eliminate all the stupid users. This is frowned upon by society.
Galaxies typically form in gravitationally-bound clusters. and the super-massive black holes form at the centre of the galaxies; i.e. they co-move with the galaxies. If two galaxies from the same cluster merge, the holes at their cores do not have relative escape-velocity and end up gravitationally bound.
The interesting point in the current story is that the black hole has picked up much more velocity and escaped. I.e. it is exceptional.
Agreed, this seemed deliberately click-baity to me (and it worked!)
I've never heard the term naked black hole before.
It's a bum rap. THe rest of the universe is moving. It's staying still.
Some drink at the fountain of knowledge. Others just gargle.
...but it was too late.
They're not outside the escape velocity of the sum of the two entire galaxies. So they'll both stay in some orbit within the combined galaxy.
As they do, they keep encountering smaller star systems, which often get flung off in random directions. The net effect of these random encounters is to slow down both black holes relative to the center of mass of the combined galaxy, similar to friction. As they slow down, they sink towards the center. Eventually, they fall into orbit around each other and continued "friction" causes them to get closer until they merge.
Just hope it's streaking away from us and not towards us...
For a planet like earth, the orbital velocity is much greater than the escape velocity, even at the surface.
But galaxies are different. The speed of the milky way relative to the CMB is about the same as its escape velocity from here.
So it is very easy for two galaxies to collide at less than their escape velocity. The time-scale is tens of millions of years, at least.
Where do I point my telescope?
It must have been something you assimilated. . . .
May be it stole something?
So, the name black hole comes from the fact that this object is so massive, nothing can escape its gravitational pull, even light. So, how is it "belching deadly x-rays" or even "hemorrhaging ionized gas"?! Would something escaping it render this object not a black hole any more?
I don't think you can tell a black hole what to do. I really doubt it'll listen.
Even worse: you don't want to draw it's attention; it might want to come over and talk to you.
Don't anthropomorphize objects -- they HATE that.
If the universe is someone's simulation -- does that mean the stars are just stuck pixels?
Must...resist...Trump...joke
Table-ized A.I.
The Playboy web site will have to start an astronomy section.
Great mental image though, coupled with "naked black hole"
In space, no one can hear you scream.
Shouldn't that be "Streaking Through the Universe"?
The working theory is that (it) got shredded to bits, a bit like a paper airplane flying into a hurricane. The leftovers include... the supermassive black hole itself
Please can we call it Goatse?