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NASA Announces Discovery of 30-Year-Old Black Hole
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.
We use the European version of "discover", it's new when it's new to us :)
Live today, because you never know what tomorrow brings
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.
Weaselmancer
rediculous.
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.
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.
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.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
But a "50,000,030 year old black hole" doesn't have quite the same ring.
You are not a brain: http://books.google.com/books?id=2oV61CeDx-YC
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.
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.
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.
If it's a pulsar, it's a neutron star; degenerate matter, but matter still, and not a black hole.
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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.
I may agree with what you say, but I will defend to the death your right to face the consequences of saying it.
I'm not sure the Bad Astronomer understands this properly... an accretion disk could certainly form around a neutron star as well...
I know of a younger one. It actually just happened. Sorry though, the light from the supernova won't be here for 50,000,000 years. Go ahead, prove me wrong! ;p
I do not respond to cowards. Especially anonymous ones.
"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?
Would that be a BHILF?
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 deal with the rest of the universe.) So if you're going by how the black hole feels about time, depending on the coefficient there, we might be looking at a black hole that's only a couple of weeks old.
I don't believe in time. It's a grand conspiracy designed to sell watches.
Why does *our frame* matter so? If we posit that it is in a galaxy 50 million light-years away, we can conceive of the frame of reference that contains both, no? We know it took 50 million + 30 years for the light beam and its information to reach us. To me that's a pretty definitive age. Should I not think of things that way?
Gravity Sucks
I don't know much about the Universe, but I am certain about one thing: There isn't a person alive who understands it . The people who feel a sense of superiority by deluding themselves into think they do are among some of this Space-Time's most strikingly hilarious examples of irony.
Guns don't kill people; Physics kills people! - John Lithgow as Dick Solomon on Third Rock From The Sun
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.
The enemies of Democracy are
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.
Not a typewriter
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)
"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.
He could argue, and argue and argue, that there really is a *privileged* frame of reference with regards of age; but, I'm not letting my daughter ("the object to be dated") out of sight of my shotgun.
I feel fantastic, and I'm still alive.
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!
~ In Trust, We Trust ~
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.
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.
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 straight line in any direction, and you would return to your starting point (i.e. either any point is the centre, or none of them are -- you can't visit the "real" centre). Similarly, we are beings who can only perceive 3 spatial dimensions. If the universe is a 3-sphere, then we could travel in a straight line away from Sol in any direction, and we would eventually return here. The universe may well have a geometric centre, but we can't visit it.
The expanding universe can be modelled by increasing the radius of a 3-sphere with time. At t = 0, the whole universe occupies a infinitesmal point in 4D space. As the universe "inflates", the "area" of the 3-sphere's "surface" increases (or, if you like, the 3D volume of the universe increases). This volume increase occurs evenly and at the same rate at all points in space.
The GP is entirely correct. You need to engage your brain.
Pirate Party UK
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.
Pirate Party UK
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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