NASA Announces Discovery of 30-Year-Old Black Hole 195
broknstrngz tips news of an announcement today from NASA about the discovery of a black hole in the M100 galaxy, roughly 50 million light-years from Earth. The discovery is notable because, if confirmed, it's now the youngest known black hole, born from the remains of a supernova we observed in 1979. Bad Astronomer Phil Plait explains why scientists think it collapsed to a black hole, rather than a neutron star: "The way a neutron star emits X-rays is different than that of a black hole. As a neutron star cools, the X-ray emission will fade. However, a black hole blasts out X-rays as material falls in; that stuff forms a flat disk, called an accretion disk, around the black hole. As this matter falls onto the newly created black hole, it gets heated to unimaginable temperatures — millions of degrees — and blasts out X-rays. In that case, the X-rays emitted would be steady over time. What astronomers have found is that the X-rays from SN1979c have been steady in brightness over observations from 1995 – 2007. This is very strong evidence that the star’s core did indeed collapse into a black hole." He also warns that we're not certain quite yet, and we'll have to keep our eye on it to make sure it's not a pulsar.
Don't you mean this instead? (Score:3, Informative)
He also warns that... we're not certain... quite yet, and... we'll have to keep... our eye on it to... make sure it's not a... pulsar.
Relativity of Simultaneity (Score:5, Insightful)
To all the inevitable pedantic responses about it not "really" happening 30 years old, I'll be even more pedantic. :) Relativity of Simultaneity, look it up. It's absolutely meaningless to talk of the temporal ordering of space-like separated events. In some suitable reference frame, it "really" did happen 30 years ago.
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Well, it would figure that most of the comments on Slashdot would be criticizing TFA and at the same time getting relativity wrong by reasoning as if there is some absolute clock.
Relate to this! (Score:3, Informative)
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I feel superior because I know enough about it to know I don't understand it. How's that work for your irony meter? :)
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I don't find it ironic at all. Our knowledge is greater for that very reason. The fact that you equate greater knowledge with superiority as a human being might be ironic in most places, but it is to be expected on Slashdot. ;-)br%
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Nobody who really understands science thinks they understand the Universe, but they know that they understand it in a measurably better way than others.
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Of course, traversing a wormhole is impossible, but since we're splitting hairs...
Citation please.
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You forgot the air-quotes around 'impossible'.
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When it comes to the universe as a whole, "impossible" has a permeating flavour of "we just haven't seen it yet".
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Actually, 50000031 years.
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More fun with simultaneity: http://en.wikipedia.org/wiki/Andromeda_paradox [wikipedia.org]
Re:Relativity of Simultaneity (Score:4, Informative)
To all the inevitable pedantic responses about it not "really" happening 30 years old, I'll be even more pedantic. :) Relativity of Simultaneity, look it up. It's absolutely meaningless to talk of the temporal ordering of space-like separated events. In some suitable reference frame, it "really" did happen 30 years ago.
You've got that somewhat garbled. The relevant events would be (A) a photon is emitted from the star, and (B) that photon arrives here on earth. The relationship between A and B is lightlike, not spacelike. Since they are lightlike relative to one another, they do have a well-defined temporal ordering; there is no frame of reference in which B preceded A, or in which A and B are simultaneous. Your final sentence, however, is correct.
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"there is no frame of reference in which B preceded A, or in which A and B are simultaneous."
From the photon's point of view they are simultaneous.
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See what you did?
Accretion DIsks ? (Score:3, Interesting)
Neutron Stars can have accretion disks too. (LSI 31 303 is supposed to have one, for example.)
So I am not sure I see why that is determinative. Off to read the article.
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> Neutron Stars can have accretion disks too.
Yes, but I don't think that they would emit large amounts of X-rays.
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The press release didn't say that, but that it was the decay with time that was determinative. I don't see it, but I suspect that there are some missing pieces in the paper, but not the press release, that fill in the gaps.
Bad Astronomy? (Score:2, Insightful)
I'm not sure the Bad Astronomer understands this properly... an accretion disk could certainly form around a neutron star as well...
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an accretion disk could certainly form around a neutron star as well...
I feel as if yo mamma jokes are imminent...
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Phil Plait didn't say it couldn't. Link [discovermagazine.com]
Re:Bad Astronomy? (Score:4, Informative)
It is correct to say that an accretion disk can form around a neutron star as well.
The distinguishing characteristic is that a neutron star bigger than its Schwarzschild radius. Not just a little bit bigger, but at least 11% bigger [see the Buchdahl-Bondi limit; this a theoretical limit for any perfect fluid spheres -- actual neutron stars don't come close to saturating that bound]. This means that the accretion of charged particles that is spiraling inward will eventually hit the surface, stopping the charged particles very rapidly. The radiation from suddenly stopping charged particles (Bremsstrahlung) is fairly distinctive, and is not seen here.
By contrast, an accretion disk around a black hole loses energy and eventually passes through the horizon. There is no sudden breaking and hence no Bremsstrahlung radiation It is the accretion disk and the lack of Bremsstrahlung that convinces us that the most likely candidate is a black hole.
[The reason the size limit was important is that as you get close to the horizon, redshifting makes things harder to see anyway. The point of the Buchdahl-Bondi theorem is that any perfect fluid sphere has to be about 11% bigger than the size of a black hole of equivalent mass. This limits the total redshift due to the object to a modest factor of 2, ensuring for a large class of matter (including neutron stars and all known matter to date) that the collision with the surface if it existed would be visible. This does not prevent unknown matter with exotic properties having s surface that is beyond the event horizon but close enough in the we would not see the Bremsstrahlung radition, but it is very difficult to construct "reasonable" solutions.]
Naw.... (Score:3, Funny)
Stop with all the 50,000,030 stuff! (Score:2)
Rather weak reporting... (Score:4, Insightful)
As this matter falls onto the newly created black hole, it gets heated to unimaginable temperatures — millions of degrees— and blasts out X-rays
Translation: The temperature is so high, it is somehow unimaginable using numbers. But since you are reading on, let me just pull a totally random number out of my ass and say a million degrees... wait no.. make it a millions, as in more than 1 million, which makes my claim sound sorta vague and not precise but makes it nevertheless appear I know what I'm talking about. That should cover the unimaginable bit of it. Besides, its not like you're going to check anyways so fuck it, lets and some em dashes for extra emphasis for no other reason other than because its really "HOT". I mean wow, can you imagine a place this hot? I'm just siting here in my office, thinking to myself, geeze this black hole stuff is not the usual environment I'm used to, most likely because I would have been obliterated and spit out as really "HOT" x-rays... there, you see where I'm coming from? HOT!
Nothing to See Here (Score:2)
Re:It was 30 years old, 50 million years ago. (Score:5, Funny)
We use the European version of "discover", it's new when it's new to us :)
Re:It was 30 years old, 50 million years ago. (Score:5, Insightful)
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Of course. Unless you have some magical way of getting those images to us or us to the black hole faster than the speed of light, for all intents and purposes it is 30 years old, as viewed from our frame of reference.
What a typically anthropocentric way of looking at the universe.
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Not at all. It's relativity. No frame of reference is special, but it's easier to talk about things within our own frame of reference for practicality's sake. It's only anthropocentric in the sense that we can't observe things in a reference frame other than our own.
There are astrophysics professors who insist on the idea that if the light cone hasn't hit us yet, then it hasn't happened. No matter if you agree or not, it definitely makes sentence construction easier.
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What a typically anthropocentric way of looking at the universe.
Ah, but the anthropocentric frame of reference is as good as any other.
And it's handy, so we might as well use it, until another frame of reference comes along that we like better.
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There is no such thing as 'actual age' or 'actual time interval' It is all frame dependent. In our frame, the black hole has existed for thirty years.
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Re:It was 30 years old, 50 million years ago. (Score:4, Insightful)
Why does *our frame* matter so?
Because it's the one we're observing it from. In a Relativistic universe, everything is relative to a frame of reference and you can't actually say anything about when things happen or their age outside of the context of a specific frame of reference.
Absolute frame of reference (Score:4, Insightful)
Actually, there exists a well defined frame of reference with respect to velocity. In rotation this is pretty obvious, since rotation with respect to the absolute frame causes centrifugal forces to appear.
Constant linear movement is not so easy to measure, but there's the background radiation dipole that can be measured and defines an absolute velocity with respect to the universe.
We cannot define one point as an absolute origin, but we can define one state as being "standing still" with respect to the absolute origin, both in rotation and in translation.
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Actually, there exists a well defined frame of reference with respect to velocity. In rotation this is pretty obvious, since rotation with respect to the absolute frame causes centrifugal forces to appear.
You don't need an absolute reference frame for that.
Constant linear movement is not so easy to measure, but there's the background radiation dipole that can be measured and defines an absolute velocity with respect to the universe.
The CMBR dipole makes a convenient measuring stick for comparing the velocit
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No, it didn't.
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Why not prefer the frame of reference of the hole itself, where the age is zero?
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Actually, isn't the hole's rest frame the one where it is the oldest, since it's spending all its motion in time direction rather than space direction? Or, in other words, it's the only frame where time dilation doesn't slow the rate of time for the hole.
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Why does *our frame* matter so?
Because I'm the center of the fucking universe - I post on /.!
Re:Because everyone else will say it too... (Score:5, Insightful)
It's not that hard to figure out. We're looking at what a 30-year old black hole looks like, regardless of how long it took that light to get here.
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It's not that hard to figure out. We're looking at what a 30-year old black hole looks like, regardless of how long it took that light to get here.
Yeah, totally agree. Can even remove the actual age of the object by saying:
We are looking at the birth and first thirty years of data after the black hole formed.
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Time is pretty meaningless when you're talking about black holes. The closer you get to the thing, the slower time goes. The only frame of reference in regards to time that has any meaning is ours, observing it.
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It's not that hard to figure out. We're looking at what a 30-year old black hole looks like, regardless of how long it took that light to get here.
But since it's a black hole, that means the light is actually going the other way, from here to there.
And the most important thing to know in these situations: stop digging.
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But a "50,000,030 year old black hole" doesn't have quite the same ring.
Re:Because everyone else will say it too... (Score:5, Informative)
From our point in space, it is 30 years old.
But, more to the point, what we're observing now is a 30-year-old black hole. It's just that over where the black hole is, it's no longer 30 years old. That's not particularly relevant to us on Earth.
Not a black hole just yet (Score:2)
Actually, it's not really a black hole yet. Not even now, 50 million years after the supernova. At least not in the reference frames that most of us are using. As the collapsing star gets more and more dense, its enormous gravity will warp space-time so that local time effectively comes to an asymptotic standstill from our point of view. This thing is, and forever will be, something that's about to become a black hole. Unless you fall into it, of course. Then your watch will join the local reference frame a
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It all depends on your frame of reference doesn't it, and in the absence of an absolute universal reference I shall accept earths as a reasonable and practical substitute. And seeing as from earth that black hole is 30 years old thats the age I'll accept, anything else is pointless pedantry.
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... seeing as from earth that black hole is 30 years old thats the age I'll accept, anything else is pointless pedantry.
Ah, but to a lot of us, pointless pedantry can be a lot of fun.
(I figured that was a better way to express it than "Whoosh!" ;-)
Re:Because everyone else will say it too... (Score:5, Insightful)
"No, it's 50,000,030 years old no matter where you are."
Uhm. I'm moving at 0.8c. It looks very much like 25000015 years old to me.
Are you suggesting that there's a global frame of reference?
Re:Because everyone else will say it too... (Score:4, Interesting)
"Are you suggesting that there's a global frame of reference?"
No, but he could argue that there's in fact a *privileged* frame of reference with regards of age: the one centered on the object to be dated.
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wouldn't the more important and more useful "privileged" frame of reference (to us) be the one that we are viewing it from?
all the data we are receiving from this object is showing us what how it appeared 30 years after birth. so for all our purposes it is 30 years old. we can't see how it looks at 50 million years of age unless we wait 50 million more years, or learn how to break the speed of light barrier.
another issue, from our perspective we know that it happened in 1979, so we know that from our pers
Re:Because everyone else will say it too... (Score:4, Funny)
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Uhm. I'm moving at 0.8c. It looks very
0.8c relative to what?
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Relative to whatever is making that whooshing sound.
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Maybe you were kidding but, "the place where the big bang happened" is located in the past, and everywhere on the expanding bubble of the spacetime manifold that is our observable universe is equidistant from it. So you can't point to the big bang -- any point could arbitrarily be the center of the universe.
Re:Because everyone else will say it too... (Score:5, Interesting)
There's an obvious universal frame of reference: measure everything relative to the place where the big bang happened. Your choice of axes is somewhat arbitrary, though.
This is a common misunderstanding of the big bang theory.
There is no center. It didn't start at a "location". The entire universe is evenly expanding, from everywhere.
They common analogy is to reduce the 3D space of the universe to a 2D example. Imagine two points on the 2D surface of a balloon. One point is you ("the observer"), the other point is something distant, like a star, that you are observing. Now inflate the balloon. The result is that the two points move apart, because space (the rubber of the balloon) is expanding. A line drawn between the two points would be longer and longer. Note that neither point is "special". Both points observe the same symmetric effect: the other point moving away.
The real universe is a lot like this, except instead of a 2D surface expanding, it's a 3D volume expanding. There's no "center", all of the points move away from each other. From the point of view of each observer, they are the center.
More accurately speaking, each observer is the center of their own private spherical "observable" universe expanding away from them. The center of the universe is your own head. 8)
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Does that mean that the ends of the universe are connected to each other? So if the universe is small enough, we could see the same objects multiple times, from Light that went around a few times? Maybe there is only one Galaxy, ours.
That is religion starting material. I claim copyright.
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If it has edges, it has a center. Hell, if its finite it has a center. Oh wait, did you do shrooms?
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A common (probably simplified) model for the universe is a 3-sphere (i.e. the set of points equidistant from a single point in 4 dimensions). A more familiar 2-sphere (e.g. a basketball) is the set of points equidistant from a single point in 3 dimensions. Imagine that you were a being that can only perceive 2 spatial dimensions. You would perceive a sphere as being a world in which you could travel in a strai
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so...they were right many hundreds of years ago when they thought the earth was the center of the universe...
i am being serious here.
It's not! Your own head is, not "the Earth", unless your head is at the center of the Earth!
An interesting metaphysical concept is that if you define the universe as the "observable universe" around an "observer", then it's still not 100% clear where there "center" is, because the human brain is not a mathematical point, it is an extended object! That is, there's a distinct "observable universe" around each infinitesimal point in your brain, but your brain has a large volume of those with a significant dist
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The big bang happened right here, for any value of "here".
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Troll? Go get 'em metamods. I'd love to know how a logical argument relevant to the conversation qualifies as a troll.
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We would need to see the edge of the universe to pinpoint its center.
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Sorry, completely irrelevant to my suggestion, try reading and understanding it yourself.
Hint, just because the frame can render in-frame measurement irrelevant doesn't mean we can't agree on a universal frame of reference. For example, we could decide that alpha centauri is the universally agreed upon fixed frame, and measure all velocities relative to that. In fact Galilean invariance GUARANTEES that we can do just that.
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No, it's 50,000,030 years old no matter where you are
And this is where you failed modern physics.
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I thought the whole point of relativity was that it's not just observation that's limited by the finite and constant speed of light in a vacuum, it's that time itself is relative based on relative velocity and acceleration. E.g., we might well be seeing a 50,000,029 year old black hole, based on the way that time passes over there relative to us.
I also was under the impression that time slows down to a crawl within a black hole. (Some sci-fi I read once, aliens cooped themselves up in one to not have to dea
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Any astrophysicists around?
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Indeed, the black hole is actually zero years old, not 30, and not 50M+30.
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Exactly. It is, and forever will be, something that's about to become a black hole. Unless you happen to fall into it. In that case, as your watch joins the local reference frame, the black hole will actually form (from your point of view) and suck you in. Outsiders will just see you approaching the thing-that's-almost-a-black-hole, and your watch slowing to an imperceptible crawl, freezing you in time.
But then what happens when the black hole evaporates through hawking radiation and the event horizon disappears?
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But then what happens when the black hole evaporates through hawking radiation and the event horizon disappears?
That will only happen after the black hole has fully formed and matter has stopped falling into it. Which, in our reference frame, is never. It only ever evaporates in local time.
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But then what happens when the black hole evaporates through hawking radiation and the event horizon disappears?
That will only happen after the black hole has fully formed and matter has stopped falling into it. Which, in our reference frame, is never. It only ever evaporates in local time.
The physics of cosmological singularities: breaking your brain since 1915.
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The physics of cosmological singularities: breaking your brain since 1915
My brain didn't exist in 1915! </pedant>
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The black hole is large enough that it swallows more matter than it burns in radiation.
Think of it as a fat slob too tubby to exercise.
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"I also was under the impression that time slows down to a crawl within a black hole."
It really doesn't matter since the energy we are seeing comes from the outside of the black hole, it's not emited by the black hole itself (it is black, after all). On the other hand, it perfectly can be the case that Relativity simply doesn't work for black holes (so Relativity, both special and general are wrong/incomplete theories).
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It's 50 million years old over in the point in space where it's located, but it's only 30 years old over in the point in space where we're located.
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You are scientifically inaccurate, yes.
There is no absolute clock. For a particular event, there is no defined point in time where all points in space agree on when the event occured. A separation in space is also a separation in time.
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And so you should, because they are wrong. We would have to be 50,000,030 years in the future to observe that black hole at the age of 50,000,030. Not only are they being pedantic, but they're also just plain wrong.
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No, it's 30 years old, it's just 30 years old to us. [wikipedia.org]
Remember what the Big E said about time being relative to the observer, y'know.
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You are not pendantic, no, you are just wrong. There is no such thing as simultaneity, and you can not make an absolute statement of the age of the black hole. It will be between 30 years and 100 million plus 30 years, depending on your reference frame. It is pointless to bicker about it.
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If it's a pulsar, it's a neutron star; degenerate matter, but matter still, and not a black hole.
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If it's a pulsar, it's a neutron star; degenerate matter,
Geeze. Judgmental anyone?
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Because it is below the schwartzchild radius. This means that the electro-strong and electro-weak forces become impotent, and normal matter interaction becomes impossible. What results is an "object" of infinite density, but finite mass. Hence, "Singularity."
Neutron star matter is just a teeny weenie bit above this critical limit, and still has enough charge force to prevent gravitational collapse. It is the most dense material in the universe that is still recognizable as matter.
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Would that be a BHILF?
In Soviet Russia... (Score:2)
...BHLFY.
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You don't see any pulses from a pulsar unless you are in the plane of the beam.
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or the x-rays hit something else that reflects them back to you... but it would have to be something within 30 light years of the (potential) pulsar. That sphere keeps expanding...
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Escept that as someone else noted if you were moving toward it at .8c it would only be 25 million light years away.