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Colliding Galaxies Reveal Colossal Black Holes
Posted by
CmdrTaco
on Thu Oct 16, 2008 11:22 AM
from the duck-and-cover dept.
from the duck-and-cover dept.
Matt_dk writes "New observations made with the Submillimeter Array of telescopes in Hawaii suggest that black holes — thought to exist in many, if not all, galaxies — were common even in the early Universe, when galaxies were just beginning to form. Astronomers have found two very different galaxies in the distant Universe, both with colossal black holes at their hearts, involved in a spectacular collision."
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Apparently. . . (Score:5, Funny)
the web site has become a black hole as well.
Re: (Score:3, Informative)
Re:Apparently. . . (Score:4, Insightful)
It was particularly evil to have the link in the words 'spectacular collision' :/
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Re:Apparently. . . (Score:5, Funny)
I wanted pictures of the black holes. Black hole photography can be pretty tricky - None of my pictures ever seem to come out. Just can't seem to get enough exposure on the film...
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Re:Apparently. . . (Score:5, Funny)
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Many amateur photographers have difficulty not to letting their thumb rest on top of the lens.
Although in this case that might actually be the best place for it.
Re:Apparently. . . (Score:5, Funny)
Parent
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Would it really be fair to say they ever approached colossal?
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Would it really be fair to say they ever approached colossal?
They have to approach 'heart' first.
Re:Apparently. . . (Score:5, Informative)
http://www.stfc.ac.uk/KE/Ind/SubArrBH.aspx [stfc.ac.uk]
Parent
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And for anyone else who was fooled, when the parent says "picture" he means it.
It is not a photograph. It is a rendition of what some artist thinks it'd look like.
"spectacular collision" with no photos = FAIL (Score:2, Funny)
Pictures please!
Or would that be considered "galaxy pron" ?
Re:"spectacular collision" with no photos = FAIL (Score:5, Funny)
Parent
Re:"spectacular collision" with no photos = FAIL (Score:5, Funny)
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I knew a girl once that I would say had a glowing blackhole...it really was spectacular. OHHHHH /andrewdiceclayvoice
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Re:"spectacular collision" with no photos = FAIL (Score:4, Informative)
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It doesn't seem that surprising. (Score:5, Interesting)
I don't think that discovering early black holes is all that surprising given that concentrations of matter were much greater early on.
What I want to know, is how did the universe expand beyond its own swartzchild radius?
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If one considers the law that matter/energy can neither be created or destroyed, the answer would have to be that the universe is just the exit point for the blackhole preceding it. And so on. You've heard of the infinite loop? ;)
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I'm not following you at all - matter going into a black "hole" doesn't get destroyed. There's no need for it to "come out" anywhere It's not literally a "hole" - it's just an indredibly (unfathomably) dense object.
Technically the black "hole" in the center of our galaxy is still a little spherical ball of matter and energy just like any other object - it's just that the density is high enough that gravity starts to behave strangely close to it.
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Exactly.
Compress it all into a neat little ball, and at some point, that ball will go bang. Maybe a Big Bang. What do time and other dimensional characteristics look like after the event? Something like us?
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Compress it all into a neat little ball, and at some point, that ball will go bang.
Actually the evidence suggests that you if you keep compressing the ball a bang becomes very unlikely. Once matter is pile onto the singularity, about the only way it seems to come back off it through Hawking Radiation, which is more of a "Little, Slow, Trickle" than a Big Bang.
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What I want to know, is how did the universe expand beyond its own swartzchild radius?
Depending on what you take the mass of the universe to be (and age too), we may not have hit it yet.
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Re:It doesn't seem that surprising. (Score:5, Interesting)
What I want to know, is how did the universe expand beyond its own swartzchild radius?
It didn't.
To compute the Schwarzschild radius [wikipedia.org] of the universe, we need to know its mass. Recent measurements suggest that the universe is flat [wikipedia.org], and so may have infinite mass. However at a minimum we can count up the mass within the observable universe [wikipedia.org]. The observable stars in the universe have a mass of ~2*10^52, but they are overwhelmed by dark matter, which brings the total mass within our observation volume to ~4*10^53 kg. So the Schwarzschild radius for the universe is:
r = (2*G*m)/(c^2) = 2*(6.7E-11 m^3kg^-1s^-2)*(4E53 kg)/(3E8 m/s)^2 = 6E26 m = 60 billion light-years.
Since the observable universe is ~46 billion light-years in radius, this means that the Schwarzschild radius of the universe is bigger than what we consider to be "the universe." In other words, we are well within the Schwarzschild radius, leading some people to describe the universe itself as a massive black hole that we are actually inside of.
The universe probably has a mass larger than what we can observe, making the radius even larger than the above estimate. If the universe truly has infinite mass, then the radius is infinite. In other words, the universe may not have a Schwarzschild radius at all.
This is also a decent description. [nasa.gov]
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Since the observable universe is ~46 billion light-years in radius, this means that the Schwarzschild radius of the universe is bigger than what we consider to be "the universe." In other words, we are well within the Schwarzschild radius, leading some people to describe the universe itself as a massive black hole that we are actually inside of.
Not according to the Wiki [wikipedia.org]...
The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is a characteristic radius associated with every mass. It is the radius for a given mass where, if that mass could be compressed to fit within that radius, no known force or degeneracy pressure could stop it from continuing to collapse into a gravitational singularity.
If the universe is smaller than its Schwarzschild radius, it should collapse into a singularity. It hasn't, so it apparently isn't.
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The universe is supposedly expanding, not collapsing.
Re:It doesn't seem that surprising. (Score:4, Informative)
If the universe is smaller than its Schwarzschild radius, it should collapse into a singularity. It hasn't, so it apparently isn't.
As mentioned here [nasa.gov], the concept of a Schwarzschild radius is one limiting case of Einstein's equations of general relativity. It is a useful concept with various rules-of-thumb, but one must be careful in applying it to all situations. In particular, the approximation breaks down, and a full treatment using the equations of general relativity is instead necessary, for "extreme" situations (like inside a black hole, during the big bang, when applied to the entire universe, etc.).
More specifically (this site seems to explain it somewhat [ucr.edu]), the "Schwarzschild black hole" is just one solution to the equations of general relativity--it is a limiting case for nominally static matter (that is also non-rotating, spherically symmetric). Other solutions are required in other cases (e.g. the Kerr solution for rotating black holes [wikipedia.org]). The Schwarzschild solution doesn't apply to dynamic systems (e.g. rapidly expanding matter). In particular the big bang and subsequent expansion of the universe represent a different solution to the equations of GR. This solution provides for a roughly flat space but massive expansion (hence highly curved spacetime, as one would expect for such high mass-density). Our best understanding suggests that inflation [wikipedia.org] occurred (where space was expanding faster than the speed of light, although light/energy/matter/information was still constrained by c).
In my previous post I was just pointing out that the expected size for the Schwarzschild radius is very large. However that is based on a naive application of the usual rules-of-thumb. The big bang, if you will, is extreme enough that it requires a more careful treatment. Moreover, our best data right now suggests that the universe is roughly flat and infinite (and thus with infinite or at least extremely large mass), meaning that there is probably no meaningful way to apply the "Schwarzschild radius" concept to it.
Disclaimer: I'm not a cosmologist. Hopefully I didn't make a mistake.
Parent
Re:It doesn't seem that surprising. (Score:5, Interesting)
Schwarzschild radius: [wikipedia.org]
The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is a characteristic radius associated with every mass. It is the radius for a given mass where, if that mass could be compressed to fit within that radius, no known force or degeneracy pressure could stop it from continuing to collapse into a gravitational singularity.
Thanks a lot... Before I was peacefully ignorant, but now you've tossed out a perfectly good question and revealed to me yet another topic for my List of Things I Know That I Don't Know...
Parent
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Man, for a moment I thought you were making a Spaceballs [imdb.com] joke, instead of a physics [wikipedia.org] reference. :-P
Cheers
What I want to know. (Score:2, Interesting)
Is how to answer my 5-year old's question of: "Ok, but whats outside the universe?"
She gets solar systems, and has a pretty good handle on galaxies and that there are lots and lots of them. I'm still trying to explain the Big Bang, and keep getting hung up on what the universe is expanding INTO.
I know, even us Big People don't have a good answer, but what the heck do you tell a kid?
"Spectacular collision"? (Score:5, Funny)
Nothing survives.
Oh, and as the mass increases, time slows down in the vicinity. Or at least that's how it seems.
The science (Score:5, Informative)
http://arxiv.org/abs/0808.2188 [arxiv.org]
In those galaxies (Score:2)
...must be millions of inhabited worlds, each populated by beings that believed themselves to be the center of the very universe, each believing that their existence had so much significance on the cosmic scale that this would not happen to them.
Instead they find themselves in the most sucky situation in the entire galaxy...
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Highlights from TFA (Score:5, Informative)
4C60.07 - the first of the galaxies to be discovered - came to astronomers' attention because of its bright radio emission. This radio signature is one telltale sign of a quasar - a black hole, spinning rapidly, feeding on its parent galaxy. A new image captures the moment, approximately 12 billion years ago, when this galaxy ripped a stream of dusty gas from a neighbour.
"This new image reveals two galaxies where we only expected to find one," said Professor Rob Ivison ... "Remarkably, both galaxies contain super-massive black holes, each capable of powering a billion, billion, billion light bulbs. The implications are wide reaching: you can't help wondering how many other colossal black holes may be lurking unseen in the distant Universe?"
Due to the finite speed of light, we see the two galaxies as they collided in the distant past, less than 2 billion years after the Big Bang. By now the galaxies will have merged to create a football-shaped elliptical galaxy. Their black holes are likely to have merged to form a single monstrously large black hole.
"These two galaxies are fraternal twins. Both are about the size of the Milky Way, but each one is unique"
From the thats-a-lot-of-lightbulbs department?
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Remarkably, both galaxies contain super-massive black holes, each capable of powering a billion, billion, billion light bulbs. The implications are wide reaching
- yes, the implications are wide reaching. Where exactly are we going to get that many light bulbs from? We can't just let all that energy go to waste. Did anyone notice Usama bin Laden in close vicinity to the black hole? If so, can we please notify Bush?
Layman's question (Score:3, Interesting)
I know I aught be able to work this out myself, but I'm not sure if general newtonian calculations would be accurate. Is it possible to orbit a black hole from inside the event horizon if it is big enough? It seems intuitively obvious that if you can't achieve escape velocity you shouldn't be able to reach an orbital velocity either but I thought I'd see if someone was willing to give a more solid answer.
Re:Layman's question (Score:4, Insightful)
No.
Maintaining an outward velocity = c would keep you at the event horizon indefinitely. Add a sideways component and you'd be able to orbit, but at velocity > c. Anything lower and you'd need velocity > c just to maintain height, much less to orbit.
If you could go fast enough you might be able to make a few passes in some sort of collapsing orbit, but a stable orbit would be impossible.
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Maintaining an outward velocity = c would keep you at the event horizon indefinitely.
The concept of standing still while having an enormous velocity makes my head hurt and my heart long for obedience to Newtonian physics.
Who really wrote this article? (Score:3, Funny)
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You could have at least made a goatse reference. Damn it man, it was right *there*.
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Re:Very simple, actually (Score:4, Funny)
Lead on, we're right behind you.
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Feel free to go for a galactic swim, oh great enlightened one.
You should be able to get there just by jumping, since gravity holds no power over you!
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Eventually he will actually find out that black holes really do suck.
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At least the snuggle afterward.
Re:Very simple, actually (Score:4, Insightful)
I would encourage you to study what a black hole actually is, rather than trusting some random sci-fi author's unsubstantiated notion that the layman's term "hole" must mean "magical portal to another dimension".
Our present equations yield a value of "infinite" when solved for the conditions believed to exist at the center of a black hole. This is likely to only mean that our equations are buggy and need fixing.
It is not the opinion of most scientists that anything special would happen inside a black hole. If you could somehow build an infinitely resilient spaceship that could somehow shield you from the effects of extreme gravity, and assuming we are wrong about the speed of light, and that you could possibly go faster than it, the most you would be able to do with a black hole would be to go in and out of the event horizon unscathed, or perhaps bang into whatever form of extremely compressed matter exists at its center. We have no reason to believe otherwise - wormholes, however prevalent they may be in the realm of science fiction, are just an unlikely hypothesis in the world of real science. For them to exist, strange forms of matter with negative density would have to be discovered, and nobody but the wishful thinkers seriously believes in that.
(I am not a physicist, however, and as such I welcome factual corrections and additions to this post)
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