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There's a Hole in the Middle of It All

michael posted about 12 years ago | from the bang-caused-the-hole-in-the-middle-of-it-all dept.

News 693

Apparition writes "CNN is reporting that the star at the center of our galaxy is actually a super-massive black hole. The article then claims that it occupies a volume of space about 3 times that of our solar system. If my math is correct, about 230 million suns could fit into that same volume, so it doesn't impress me that the claimed mass of the black hole is only between 2.6 and 3.7 million times that of the sun. So what is up here? Since when do black holes occupy so much space (I thought they were points)? And how can something with a density only 1/100 of our Sun be called super-massive?" I think the article is talking about a maximum possible size of the object, due to limitations on the resolution of our instruments. Nature has a no-registration story about the research. Update: 10/16 23:44 GMT by M : There's an article with more information on space.com, and a press release from the European Southern Observatory.

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ya harasho! (-1, Offtopic)

Anonymous Coward | about 12 years ago | (#4464590)

gorovit meenya zavoot, syeka! Da!

Re:ya harasho! (-1, Offtopic)

Anonymous Coward | about 12 years ago | (#4464774)

shlunga pashtro mokoshtur maavrik!!!

Re:ya harasho! (-1, Offtopic)

Anonymous Coward | about 12 years ago | (#4464791)

www.goatse.cx

Event Horizon (5, Insightful)

redbaron7 (577469) | about 12 years ago | (#4464602)

Usually when people talk about the size (as in diameter & volume) they are talking about the Event Horizon, NOT the singularity.

RB

Re:Event Horizon (5, Informative)

Transient0 (175617) | about 12 years ago | (#4464679)

It's true that often when the size of a black hole is mentioned, it is the Swartzchild radius or "Event Horizon" that is being mentioned, being it's apparent size to our instruments.

It is not however true that black holes are points. A black hole that became a point gravity source is what is referred to as a singularity. It was a singularity that became the big bang and if the "big crunch" theory is correct, it will probably be a singularity that the universe ends as, but under any other circumstances the creation of a singulairty would require a set of events so astronomically unlikely that it is not believed that any do have or will come into existence during the lifetime of the universe. So in fact black holes DO have a radius, but considering the tremendous size quoted here, I imagine they are in fact referring to the Swartzchild radius.

Re:Event Horizon (5, Interesting)

benwb (96829) | about 12 years ago | (#4464751)

Current theories in no way preclude the formation of a singularity. In fact it is pretty much the required outcome when a sufficiently massive start reaches the end of it's life. There is some discussion that when quantum theory and gravity are unified quantum effects may smear the singularity out of existence, but at this point it is all hand waving. Perhaps what you're thinking of is a naked singularity. A naked singularity is a singularity that is not cloaked by an event horizon, and is extraordinarily unlikely to occur.

Re:Event Horizon (5, Informative)

Zack (44) | about 12 years ago | (#4464803)

Current theories in no way preclude the formation of a singularity.

True, but current theories also haven't proven that inside a black hole _is_ a singularity. Although it's been a while, I remember from an Astronomy class I took that due to the rate of spin outside the black hole, and that conservation of momentum would mean it would spin faster inside means that the odds of a true point singularity are relatively low.

But what do I know? ;-)

Re:Event Horizon (2)

Trinity-Infinity (91335) | about 12 years ago | (#4464780)

"You can't leave.. the ship won't let you!!

size (5, Informative)

Satai (111172) | about 12 years ago | (#4464605)

The "size" of a black hole is, in fact, the size of the Schwarzchild Radius, which is the distance at which neither light nor matter can escape. The black hole itself, the singularity, is indeed a point of infinite density.

Re:size (5, Informative)

u19925 (613350) | about 12 years ago | (#4464735)

The "size" as used in the article is the observed radius within which a massive object (need not be a BH) is located. The mass is inferred from orbital time and distance of a nearby star. The physicists argue that there is no model for any object to be so massive (2-3 million times the Sun) and so compact (radius less than few times solar system) and yet it can prevent self induced gravitational collapse. Therefor the object must be a BH.

The black hole (of the mass of several million times that of sun) at the center of the Milky Way galaxy, has been suspected for decades. However, as observations keep on shrinking the confinement radius, it keeps on ruling out other potential models.

Infinate density (0)

Anonymous Coward | about 12 years ago | (#4464763)

I'm an expert on quantum physics, but surely if a black hole's singularity is "infinate density" in the literal sense of the term, then all matter in the universe will be pulled in by its infinate gravity as fast as possible?

Opps (0)

Anonymous Coward | about 12 years ago | (#4464787)

God I'm tired. I meant to say I'm not an expert on quantum physics!

Re:size (3, Insightful)

frovingslosh (582462) | about 12 years ago | (#4464802)

The "size" of a black hole is, in fact, the size of the Schwarzchild Radius, which is the distance at which neither light nor matter can escape. The black hole itself, the singularity, is indeed a point of infinite density.

Actually, current theories including string theory prevent the infinite point claims, but get to the next best thing (something in the order of 10 to -37 meters if I recall right).

The size reported makes no sense though for a Schwartzchild radius of a black hole with the indicated mass, it's way way too large.

Watch that title (3, Funny)

Corporate Troll (537873) | about 12 years ago | (#4464606)

....now really, do they do this on purpose? I mean, I don't even want to see all the Troll links to goase.cx pointing out what to find in the hole.
It's just disgusting!

meep? (1, Insightful)

Anonymous Coward | about 12 years ago | (#4464608)

I feel so small.

So how long... (-1, Funny)

name_already_in_use (604991) | about 12 years ago | (#4464610)

until the super-massive black hole eats up our galaxy, and do you think M$ will survive?

Re:So how long... (4, Funny)

Anonvmous Coward (589068) | about 12 years ago | (#4464638)

"...until the super-massive black hole eats up our galaxy, and do you think M$ will survive?"

It's nice to see that graduates from the Bob Saget School of Comedy are getting journalism work.

Re:So how long... (0, Offtopic)

name_already_in_use (604991) | about 12 years ago | (#4464681)

I do not who Bob Saget is, but accroding to this [geocities.com] he is God, so I'll take that as a compliment ;)

Re:So how long... (0)

esac17 (201752) | about 12 years ago | (#4464748)

So how long did it take you to create that webpage just to refute his post? ;)

Why, that's no hole! (0, Offtopic)

Chagatai (524580) | about 12 years ago | (#4464611)

It's CowboyNeal!

Nice try, fag boy (-1, Troll)

Anonymous Coward | about 12 years ago | (#4464661)

better luck next time karma slut

What is Size? (2, Redundant)

BoBaBrain (215786) | about 12 years ago | (#4464613)

The size of the black hole isn't the volume taken up by its mass. It's the volume inclosed by the event horizion.

If light enters that volume, it never(ish) gets out.

Re:What is Size? (2)

Lumpy (12016) | about 12 years ago | (#4464789)

ok so I have a question....

at what point then does light get radically bent?
there should be a layer where light coming from me will get bent around 180 degrees and fired back at me.

doesnt this make sense? it shoud in fact be possible to find a trajectory point that will return your light back to you.

Volume claimed shouldn't be for the hole itself (0, Redundant)

KoopaTroopa (549540) | about 12 years ago | (#4464614)

The matter in a black hole should be condensed down to a point. The event horizon is what would be many times as large as our solar system.

Such an event horizon would take a whole lot of matter :)

Size matters (1)

DdJ (10790) | about 12 years ago | (#4464615)

So what is up here? Since when do black holes occupy so much space (I thought they were points)? And how can something with a density only 1/100 of our Sun be called super-massive?
Well, are we talking about the radius from the center to the surface of the matter, or from the center to the event horizon, or from the center to the radius at which it's possible for other stars to be stable, or what?

it must be a point... (1)

dfj225 (587560) | about 12 years ago | (#4464617)

The whole idea behind a black hole is that it is a point with the mass of a star. If it was the size of a star with a really large mass, then it would just be a big star. I really don't believe that a black hole can occupy a volume, else it wouldn't work.

Re:it must be a point... (1)

EatHam (597465) | about 12 years ago | (#4464695)

If a black hole contains matter, then it must occupy some volume. Even if there are no spaces whatsoever between the electrons, protons, and neutrons, those particles themselves have a (really small) measurable volume.

Re:it must be a point... (1)

dfj225 (587560) | about 12 years ago | (#4464718)

Yes, but the point is (no pun intended) is that the size of this black hole would be abou the size of maybe a pen point (not something with very much volume and certaintly not one with the size that they claim.)

Re:it must be a point... (1)

EatHam (597465) | about 12 years ago | (#4464740)

Sure, but it's not that black holes can't occupy a volume or they won't work. It's the density that makes them a black hole, not the amount of volume they take up. I suppose theoretically, it would be possible to have a black hole that had the actual volume of our sun. That would be one f'n large black hole though. <rabbit trail>If I recall correctly, Steven Hawking theorized that all the matter in the universe was condensed to approximately 1cc in volume prior to the big bang. Too lazy to google it though</rabbit trail>

Hollow Earth theory? (1, Insightful)

Anonymous Coward | about 12 years ago | (#4464618)

This reminds me of the hollow earth theory... which is proven to be complete bullshit.

I'm not sure if this article presents a convincing enough argument in favor of the black hole argument.

Thoughts?

Re:Hollow Earth theory? (0)

Anonymous Coward | about 12 years ago | (#4464654)

Thoughts?

Just one: Stephen Hawking believes there is a
super massive black hole at the center of our
galaxy.

Most cosmologists now believe the same. This is,
like, really *old* news.

Sad news, Stephan Hawking found dead, 58 (-1, Troll)

Anonymous Coward | about 12 years ago | (#4464683)

The key word being believes .

Event Horizon != Actual size (2, Redundant)

jimbo3123 (320148) | about 12 years ago | (#4464619)

The large size is probably the event horizon for the black hole.

The event horizon is the sphere within which not even light can escape from the black hole. It is the dark area the the black hole appears to take up.

The actual size of the object would be much smaller

They're talking about... (0, Redundant)

john_roth (595710) | about 12 years ago | (#4464621)

the size of the event horizon. What's inside is unknown (and presumably unknowable)

John Roth

Re:They're talking about... (2, Insightful)

AyeRoxor! (471669) | about 12 years ago | (#4464667)

"What's inside is unknown (and presumably unknowable)"

Actually, it is completely knowable. It's just impossible to relay that information outside the event horizon. :-P But in theory, even if for no purpose and getting no proof, a probe could make it past the event horizon, if only an extremely small amount. Maybe even a manned module. I forsee these "suicide trips" in the future, as opposed to a KevorkianBot.

Re:They're talking about... (2, Informative)

davidsansome (563576) | about 12 years ago | (#4464689)

> (and presumably unknowable)

You could go in and find out, but due to time dilation, you would see the rest of time flash before your eyes, and then witness the end of the universe. You wouldn't be able to tell anybody though, because no signals can escape unless they travel faster than the speed of light (which is of course impossible). You would also be dead, but that's another story.

Re:They're talking about... (3, Informative)

luzrek (570886) | about 12 years ago | (#4464756)

From General relativity when you cross the event-horizon, the role of the time coordinate and the radial distance coordinate switch. This results in being able to move back and forth in time, but not being able to move away from the center of the black hole. Slightly more relevant to this discussion is the conversion between the mass of a black hole and the radius of the event horizon (assuming spherical symmetry) is:

Radius = 2 * "Universal Gravitational Constant" * "mass inside event horizon" / pow("speed of light",2)

For a black hole the mass of our sun the radius is:

Radius = 2 * (6.67 * 10^-11m/kg/s^2) * (2 * 10^30 kg) / (3 * 10^8 m/s)^2 = 2.964 km

When you check my math make sure you get your units right. A black hole three times the size of our solar system would be quite massive, and you should be impressed.

Also, I saw a program on Discovery Channel a while ago (6 months+) which had an interview with an observational astronomer in which he claimed to have observed movement in the center of our Galaxy which was consistant only with a supermassive black hole. I guess he finally published.

I'm no astrophysicist... (1, Interesting)

AyeRoxor! (471669) | about 12 years ago | (#4464622)

"CNN is reporting that the star at the center of our galaxy is actually a super-massive black hole."

I'm no astrophysicist, but really, wtf could hold an entire GALAXY together but a black hole? Seriously, any ideas? I may be naive, but I've always thought this to be a stupid ponderance. Sure, anyone with a scientific mind would want proof of its existence, but to be surprised? *Sighhh*

Re:I'm no astrophysicist... (5, Informative)

Fnord (1756) | about 12 years ago | (#4464651)

Theoretically the mass of the galaxy itself should be enough to hold it together. Even the black hole could have originally been formed from matter collecting at the center of gravity of the galaxy.

I'm an astrophysicist... (2, Informative)

Anonymous Coward | about 12 years ago | (#4464722)

As the above reply suggests, the galaxy's own mass should be able to hold it together. Just like the sun holds together the solar system and the Earth holds itself together.

Black holes are good candidates for causing a galaxy to accumulate. It can be kind of hard to explain what causes galaxies to form.

I'm getting off-topic, but I don't care...

One of the favorite explanation comes from irregularities in mass distribution as evidenced by perturbations in the cosmic microwave background. That's one of the reasons that the CMB became such a hot topic, it offers insight into the origin of large scale order in the universe.

Also of interest to /.-ers might be a recent paper that describes the universe as a cyclical entity (no "big bang"), by representing it as a pair of branes (world sheets, see string theory...). The end result is there's an event (a "bounce) that might look like the Big Bang, but it's really just a collision between the branes.

Like anything else in cosmology, it's all rather speculative (at least as compared to many other physical models).

Find the link on your own (/. might've even covered this topic).

Re:I'm no astrophysicist... (1)

jericho4.0 (565125) | about 12 years ago | (#4464743)

An orbital system doesn't have to have a massive combination of mass at the center to hold together. The orbiting materiels velocity increases to balance the gravitational pull.

Re:I'm no astrophysicist... (0)

Anonymous Coward | about 12 years ago | (#4464753)

Any group of objects in space can "hold" themselves together as long as an outside force does not influence them. Even if an "inside" explosion pushes everything out, conservation of energy will eventually bring it all back again.(or eventually stop at infinity)

Re:I'm no astrophysicist... (5, Informative)

Michael Woodhams (112247) | about 12 years ago | (#4464796)

"but really, wtf could hold an entire GALAXY together but a black hole?"

I am (or rather, was) an astrophysicist. The answer is the rest of the galaxy holds it together, a bit like the gravity of the Earth is what holds the Earth together. The galaxy has the mass of billions of stars - so any stars not at the center are being pulled towards the center.

In answer to the original poster, the 'size' of a black hole is its event horizon radius:

R = 2GM/c^2
where
G = universal gravitational constant
M = mass of the black hole
c = speed of light.

Re:I'm no astrophysicist... (5, Informative)

helix400 (558178) | about 12 years ago | (#4464810)

wtf could hold an entire GALAXY together but a black hole?

This is a small misunderstanding. Many people seem to think that a black hole has super gravity or extra strength power just because its a black hole. Actually, it all depends on the mass.

For example, if our sun suddenly turned into a black hole, we wouldn't get sucked in. We'd still orbit our new black hole sun the same way we orbited our old normal sun. Just because it became a black hole doesn't mean its mass changed. And since its mass didn't change, we would still orbit the same.

Ditto for our galaxy. If we didn't have this black hole at the center of the galaxy, but instead 3.7 million suns, everything would orbit just the same

---
A black hole is just God dividing by zero

Event Horizon (2, Redundant)

Cheeko (165493) | about 12 years ago | (#4464623)

I think another possible explanation for the size analogy, is that the limit of the event horizon of the black hole is the size of 3 solar systems. Anything crossing that point would become part of the black hole so it makes sense to refer to the black hole as being this large, even if the condensed object is far smaller. Logic would seem to imply that the black hole is more dense or at least as dense as a star, but not being an astrophysicist, I could be wrong.

From the article: (3, Insightful)

Cyclopedian (163375) | about 12 years ago | (#4464624)

The astronomers found "unambiguously" that the central star is moving around Sagittarius A "like the Earth orbits the sun," the ESO consortium said in a statement.

So, does that mean that in time, the blackhole will swallow up the star?

-Cyc

Re:From the article: (0)

dlt074 (548126) | about 12 years ago | (#4464709)

no more likely then the sun swollowing the earth. when the sun expands into a red giant we're toast. or if an outside force acts on the earth in such a way as to destablize our orbit and we plung into it.
but unless some outside force acts on that star or the event horizon expands the star will be fine till it die's it's own natural death.

Re:From the article: (5, Informative)

delta407 (518868) | about 12 years ago | (#4464721)

So, does that mean that in time, the blackhole will swallow up the star?
Maybe, maybe not.

Comets can orbit the sun for a really long time; some smack into an object (like the sun, for instance), some escape their orbit, and some just keep orbiting. There's nothing that guarantees the star will get sucked in; it all depends on the orbital path, really. It may experience a slingshot effect and leave the black hole altogether.

Orbiting a Black Hole (5, Informative)

jaaron (551839) | about 12 years ago | (#4464754)

An object can orbit a black hole just like a planet can orbit the Sun (or a star). The Sun will not swallow or pull in the Earth any time soon. Black Holes are not cosmic vacuum cleaners that "suck" up everything around them. If you're in a stable orbit, it would be just like orbiting a Sun.

That said, there is evidence from general relativity that due to graviton radiation (gravity particles), large orbiting bodies slowly move closer to each other. The gravitons leaving such a system take energy out of the system slowly bringing the orbiting bodies together. This effect is (AFAIK) theoretical, although many people are currently working on ways to detect this graviton radiation and show that it is coming from systems like this. So in this case, yes, eventually (think eons) the star and the black hole would slowly move towards each other (the star would move more since it the least mass of the two) and in this type of collision, the black hole wins.

black hole orbiting (1)

Napalm Boy (17015) | about 12 years ago | (#4464761)

Not necessarily. It depends on things started. Celestial objects (stars, planets, black holes, comets, whatever) form orbits around massive objects based upon how they're formed and/or their entry trajectory and speed. It's quite possible for the star to be in a stable orbit around the black hole, just as Earth is in orbit around an object much more massive. The physics at great enough distances (outside the event horizon) is the same.

Now we know (4, Funny)

m_chan (95943) | about 12 years ago | (#4464626)

where Enron's accountants found work.

Space (1)

sixdotoh (584811) | about 12 years ago | (#4464627)

yeah, i thought black hole's were points too, but they also have event horizon's that extend far out form the actualy black hole point. perhaps that's what they were talking about.

What's the radius? (0)

Thud457 (234763) | about 12 years ago | (#4464706)

So, would it be possible that whole star systems are intact within the Schwarzchild radius? Could stuff be in stable orbits where tidal forces didn't rip things apart? Cool!

Clarification for submitter (1)

DrkShadow (72055) | about 12 years ago | (#4464632)

So what is up here? Since when do black holes occupy so much space (I thought they were points)?

Black holes are points, as best I know. Infinite compression sort of thing. However, their effect reaches beyond "point" status. As their gravity increases, their grip on everything also increases. Here, where they say "that it occupies a volume of space about 3 times that of our solar system" they most likely mean that light can't escape that region.

So, it is a point, but the volume, as they say it, is how far its ultimate effect (capturing light) reaches. At great distances, gravity weakens greatly, so much mass is required to reach large distances.

My clarification.

-DrkShadow

black holes ARE a point.... (2, Informative)

jokrswild (247507) | about 12 years ago | (#4464633)

Yes, black holes are a point (that's called the singularity), but they're talking about the size of the event horizon, or point of no return. So this particular black hole has a mass of 2.6 to 3.7 million or whatever suns, but its event horizon is larger than the solar system.

With a black hole this big, you can actually cross the event horizon, and not be torn apart because the change in gravity over a certain distance (6 feet or so for your height) isn't great enough. Smaller black holes will rip you apart quicker though

Re:black holes ARE a point.... (1)

jackb_guppy (204733) | about 12 years ago | (#4464715)

Prove they are a "point".

The volume of space the matter takes up could be the size of earth or bigger, but because once you cross the event horizon there is no turning back, it could be thought of as a "point". Since the math comes out "right".

Just as calculating the gravity action between two say planets use the center of there mass as the reference point of the distances between them.

Earth you saying earth then is a "point". Or is math just simpler.

Re:black holes ARE a point.... (1)

u19925 (613350) | about 12 years ago | (#4464795)

Wrong! You would be surprized to know that a perfectly happy life can exist inside a BH! Consider a supermassive BH of trillions of times that of our galaxy. Such a black hole can take billions of years to collapse into singularity. The moment the mass becomes confined within the Schwatzchild radius, it is technically a BH; but it may take long time for things inside to feel any difference! It is just that when people talk about BH, they talk about BH which have been suspected to be existing and hence we get a feeling that they have large density or that they are point like and so on.

Density, anyone? (1)

Chastitina (253566) | about 12 years ago | (#4464637)

If my math is correct, about 230 million suns could fit into that same volume, so it doesn't impress me that the claimed mass of the black hole is only between 2.6 and 3.7 million times that of the sun.

As I understand it, all the mass of a black hole is compressed into a singularity at the center of an event horizon with the volume between effectively empty. The impressive thing about a black hole is the incredible density of the compacted mass at the center, not the distance at which the black hole starts taking effect or the actual mass in the middle.

Super-Massive Black Holes (5, Informative)

Spicy_Italian (224301) | about 12 years ago | (#4464639)

According to my Astronomy course, Super-Massive black holes are less "violent" than their smaller brothers because most of the mass is concentrated at the center in a very very small space. Their event-horizons are very large because of this mass, which makes them seem not as dense as we would assume. With a small black hole, the event horizon is very small, and thus the effects near the point are much more drastic because mass that passes the event horizon is "consumed" immediately. I realize I am simplifying quite a bit, but hopefully you get the point.

kiss my blackhole slashdot!!! (-1, Troll)

Anonymous Coward | about 12 years ago | (#4464640)

you read it here first.

Achieve intellectual enlightenment (-1, Offtopic)

Anonymous Coward | about 12 years ago | (#4464641)

Down the Drain (2, Interesting)

(eternal_software) (233207) | about 12 years ago | (#4464644)

I've always thought it was obvious that super-massive blackholes lie at the center of galaxies. The intense gravity at the center should create one, and spiral galaxies are all just pinwheeling "down the drain".

I would bet there are black holes at the center of ALL spiral galaxies like our Milky Way. Other shaped galaxies may just be at earlier stages of evolution (such as elliptical) before their holes have formed.

academic implications? (3, Interesting)

smd4985 (203677) | about 12 years ago | (#4464648)

the scientists in the article seem to assert that this is CONCLUSIVE proof of a black hole's existence. but i remember reading a few months ago about a schism in the physics community - a sizable segment of the community is disputing the theoretical existence of black holes! i wonder how this discovery will affect that debate....

Re:academic implications? (3, Funny)

benwb (96829) | about 12 years ago | (#4464777)

Kip Thorne has a subscription to penthouse. They exist.

To clarify... (5, Informative)

pq (42856) | about 12 years ago | (#4464649)

Since when do black holes occupy so much space (I thought they were points)? And how can something with a density only 1/100 of our Sun be called super-massive?

The "size" of the black hole refers to the size of its event horizon (a.k.a the Schwarzschild Radius), which is R = GM/2c^2. For a huge value of M ("supermassive"), the event horizon is very large: once you cross this, there's no coming back, and our physics stops at the edge. But since R is so large, the tidal forces are small at the event horizon - much smaller than the tidal forces at the event horizon of a smaller black hole. (Chew on it for a second and it makes sense).

The "actual" naked singularity is in fact a point, but we have no way of probing anything inside the event horizon. So calculating the density of a black hole is misleading...

Re:To clarify... (5, Insightful)

Pedrito (94783) | about 12 years ago | (#4464757)

...once you cross this, there's no coming back, and our physics stops at the edge.

I'm not picking on you, others have been saying things like this too. They talk about "there's no coming back", "can't communicate to the outside", and "physics stops at the edge" and such. These are all theories, not facts. I wish people would just be a little more careful in their phrasing, as indeed, black holes themselves are still theories.

Even relativity is only a theory. But I digress.

No, physics doesn't stop at the edge, our understanding of physics breaks down at the edge. We don't know what happens because our physics deals in infinities that make no sense once you cross the event horizon. Physics still exists, it's just undefined to us.

In the same vain, communication from within a blackhole to the outside is impossible, assuming our basic theories of black holes are correct, and assuming that there's no way to communicate faster than the speed of light. Again, relativity is a theory, not a law. It's a theory that has come into question recently as well.

I'm not putting down Einstein or relativity. Amazing stuff, to be sure, but it may not be entirely correct.

Yes, a black hole is a point (1)

Nathanbp (599369) | about 12 years ago | (#4464657)

However, by size the article is likely referring to the size of the event horizon of the black hole. The event horizon is the bondrary between where light can escape from the black hole and where it cannot. As mentioned in the article, this is not a new idea, only the proof is new. Of course, we could have just sent Beowulf Shaeffer to the center of the galaxy to find this out. (See "At the Core" by Larry Niven)

So... (5, Funny)

sirgoran (221190) | about 12 years ago | (#4464659)

Would this be the proverbial drain that we're all swirling around to our eventual demise?

Just wondering.

-Goran

No... (5, Funny)

SkulkCU (137480) | about 12 years ago | (#4464752)


That's Florida.

That explains it (5, Funny)

Anonymous Coward | about 12 years ago | (#4464662)

From the very center, this galaxy sucks.

Diameter of a Black Hole (4, Informative)

Crispin Cowan (20238) | about 12 years ago | (#4464672)

So what is up here? Since when do black holes occupy so much space (I thought they were points)?
Black holes are not points. The edge of a black hole is the point at which the escape velocity (velocity required to escape the gravitational field of the object) exceeds the speed of light, and thus light can no longer escape from the object. This is called the "event horizon." [uiuc.edu]

This would seem to imply that, in theory, a very large black hole could have rather low density inside the event horizon. It seems to me that a black hole could spontaneously form around a particularly dense cluster of stars if it was large enough and they all happened to clump together.

But my head starts to hurt thinking about what happens to physics when a region of normal space suddenly finds itself inside a black hole like that. I am definitely not a physicist, so I can't explain what goes on inside a black hole, or if my globular cluster black hole is even possible.

Crispin
----
Crispin Cowan, Ph.D.
Chief Scientist, WireX Communications, Inc. [wirex.com]
Immunix: [immunix.org] Security Hardened Linux Distribution
Available for purchase [wirex.com]

Re:Diameter of a Black Hole (0)

Jock Kodimar (599124) | about 12 years ago | (#4464786)

I read, i think in Discover that they think that as you approach the event horizon that time slows down. So you could send something in but it would never really reach inside because it would get frozen in time before it reached. I dunno i thought that was kinda interesting.

Discovery Channel (1)

omegakidd (592638) | about 12 years ago | (#4464676)

I was watching a show on the Discovery Channel and they were talking about how they think that there are super massive black holes in the middle of every galaxy, or in most. I forget.

Size quoted is the orbit of a star (5, Informative)

vondo (303621) | about 12 years ago | (#4464677)

What they have found is a star that orbits the center of our galaxy at an average radius of 17 light hours and does it in 15 years. That radius is what is 3 times the size of our solar system. The event horizon of the black hole does *not* occupy all of that space.

density of blackhole (2, Informative)

Anonymous Coward | about 12 years ago | (#4464685)

when the mass (radius) of black hole is increased the density actually decreases. ofcourse the density is mass per volume and the volume of a black hole is not the same as sphere of same radius. btw. black hole can has only 3 degrees of freedom: mass, impulse momentum and electric charge. from those it is possible to derive all properties of black hole.

How many "it's the event horizon" posts do we need (3, Insightful)

Anonymous Coward | about 12 years ago | (#4464708)

Jesus people! Of the 41 posts so far, 13 of them have said the same thing... event horizon.

I can imagine the first few stepping on eachother, but doesn't anyone else bother to see what others have written before posting the same thing... over and over and over...?

Better article (5, Informative)

Anonymous Coward | about 12 years ago | (#4464711)

Space.com is carrying a more informative article [space.com] about it.

Spiral shape (0)

Anonymous Coward | about 12 years ago | (#4464712)

Notice how our galaxy is shaped like a spiral? Sort of like a whirlpool? Not a cooincidence.

We're all spiraling into the black hole.

This has been suspected for a long time (2)

f97tosc (578893) | about 12 years ago | (#4464723)

The news is that somebody made a direct observation which confirmed the suspisions and also suggested a precise location of the black hole.

Tor

Once again life imitates art... (2, Informative)

Bobulusman (467474) | about 12 years ago | (#4464729)

Anyone remember the Foundation series by Isaac Asimov? He mentions several times in those books that the center of the universe is a black hole. I can't remember the exact line, but one of them was something along the lines of, "The planet was at the center of the universe, or as close to the center as a planet could be, for the true center was a massive black hole"

It's been a few years since I've read those, but I do remember that the fact that that planet was at the "center" was a pivital plot points in one of the later books.

Oh that was a misprint... (0, Troll)

dubiousmike (558126) | about 12 years ago | (#4464731)

They meant that the black hole was located in my wallet. You see, my electric bill skyrocketed from powering up my Windows box too often.

Obligatory goatse.cx link (-1, Offtopic)

Anonymous Coward | about 12 years ago | (#4464732)

To pre-emptively prevent a deluge of goatse.cx links given the title of the story, here is the link goatse [goatse.cx] Therefore, please do not post any more links as they will be Redundant.

Thank you.

CmdrTaco

Discovery Channel makes me think I'm smart (3, Informative)

GMFTatsujin (239569) | about 12 years ago | (#4464733)

There was a show called (oddly) Supermassive Blackholes on a few months ago.

Interesting stuff -- once they were discovered to be in just about every galaxy, people smarter than me started thinking about how they formed. Conventional wisdom says that they formed after the galaxy took shape, and that stellar matter near the center collided and merged into these monsters. Another theory, however, posits that the SMBH actually triggered stellar formation in a cloud of otherwise unremarkable hydrogen.

The idea is that as the hydrogen gas fell inward and collapsed, the gas in the nearby area would heat up and glow. This is, of course, what we see. However, it goes further to say that this surrounding energetic gas could cause a sort of super-shockwave of energetic particles travelling back out through the surrounding gas, pushing it around and raising the density, causing the whispy bits to compress together to the point of fusion.

Poof! Stars born by black holes at the center of a gas cloud.

Pretty neat, I thought.
GMFTatsujin

mmmm.... (1)

s4m7 (519684) | about 12 years ago | (#4464746)

That means our galaxy is one big delicious forbidden dooooughnut.

Seriously who thought that something that exists in nature was the same as a euclidean mathematical construct? A point? I mean really. A point has NO dimention which would give your black hole INFINITE mass. My best guess is, that would give it sufficient grabbity pull the whole universe through to the scientifically documented "negaverse" and we could all hang with bizzaro superman.

Imagine a beowulf cluster of... *DOH!*

Re:mmmm.... (2)

dadragon (177695) | about 12 years ago | (#4464811)

Actually, a point with no volume would have infinite density, but finite mass. Density is defined as Mass/Volume.

Let's set mass = k, and volume = x okay?

Lim(x->0) k/x = infinity.

What's inside a point with infinite density? Who knows, but we do know that our universe has finite mass, just like black holes....

points to ponder.

Be careful! (1)

s4m7 (519684) | about 12 years ago | (#4464762)

If you read the earlier post about the kernel patch, you would know that talking about the hole may be a violation of the DMCA!

Someone Obviously Hasn't Seen Star Trek V (4, Funny)

guttentag (313541) | about 12 years ago | (#4464764)

We already know there's a powerful telepath living on a planet there and he needs a space ship. If there had been a black hole in the center of the galaxy, you'd think someone would have mentioned it.

Black hole size (5, Insightful)

Anonymous Coward | about 12 years ago | (#4464769)

The article is referring to a determination of the orbit of the star closest to the galactic center. The periasteron (closest point in the orbit) is 17 light hours from the galactic center. This implies that the mass necessary to create that orbit is concentrated within that radius. The only thing in our current cosmic zoo that fits 3 million solar masses inside of 17 light hours is a black hole. The event horizon itself should be smaller than that, but not by much.
What is an interesting question is where the Roche limit is for these parameters, and how close this star is to that limit. (In other words, how much closer can the star get before it is ripped apart.) I seem to remember that it is possible to set up conditions so that the Roche limit is inside the event horizon. Obviously, the physics around there are very strange.

Now you've done it!! (-1, Troll)

Anonymous Coward | about 12 years ago | (#4464770)

There's no WAY Star Trek 5 can come true!

You... KLINGON BASTARDS!!!

Rickety (0, Offtopic)

Phayyde (192873) | about 12 years ago | (#4464773)

I don't know. The whole thing just seems sort of rickety to me.

The math doesn't match the description! (5, Informative)

Ichoran (106539) | about 12 years ago | (#4464782)

For anyone who wants equations to go along with the descriptive posts on event horizons and Schwarzschild radius, said radius is given by
  • r = 2GM/c^2
where G = 6.67e-11 m^3/s^2*kg (the gravitational constant) and c = 3e8 m/s (the speed of light, of course). Plug in 3 million sun-masses (the sun weighs 2e30 kg), and you have
  • r = 8.9e9 m = 5.5 million miles = 0.06AU
So unfortunately, the event horizon isn't three times as big as the solar system. The earth's orbit is 1AU (that's how the unit is defined). The event horizon barely stretches past the surface of the sun (7e8 meters)!

So much for that idea!

I thought... (4, Funny)

JHromadka (88188) | about 12 years ago | (#4464788)

at the middle of the galaxy was some calm looking planet with a grey-haired guy that Sybok is looking for. Thanks for bringing up horrible memories of ST:V!

There's a Hole in the Middle of It All? (1, Funny)

orangepeel (114557) | about 12 years ago | (#4464799)

*drooling* Mmm ... donut!

Didn't Disney discover this? (1)

Beebos (564067) | about 12 years ago | (#4464801)

I thought Disney discoverd this in the eighties. http://www.geocities.com/Area51/Shire/6822/

The sniper has been identified ... (-1, Offtopic)

Anonymous Coward | about 12 years ago | (#4464812)

... but why are they keeping it a secret? Presumably not to cause widespread panic.

Why would this be? It's clear that there are only two possibilities as to who the murderer is:
  1. The sniper is a high ranking official in the US Army. This is the conspiracy theorist's favorite choice. Obviously, this is where the sniper would have received such training. And it is a convenient leftist myth that Uncle Sam's finest, faced with the possibility of fighting an unjust war, will be cracking up, fearing another Vietnam.
  2. The truth however is obvious. The sniper is a muslim. All muslims receive weekly training in the art of murder at their terrorist training camps (mosques). The reason why this fact hasn't been revealed is that it would cause the American public, as one, to rise up and eradicate the islamic filth from the country. And as the 'good guys', we don't want to appear to be racist.
Personally, I believe, along with every heterosexual Slashdot poster, that it is ABOUT TIME we did something about these rag-wearing animals that pollute our welfare system.

But alas, the leftists are in control of the media. A white kills a muslim on US soil, and it is declared a racist attack. A gang of muslims rape and murder a white woman in Saudi Arabia, and the same bullshit story of 'western alcohol bootleggers' is replayed. And our media, fearing even the slightest hint of political incorrectness, lap the story up.

Saudi Arabia are NOT our allies. And mecca shall be in ruins before the decade is through.

i once had a friend... (0)

Anonymous Coward | about 12 years ago | (#4464813)

who went to a black hole to measure its radius. never did hear back from him...

Heretofore Undisclosed Tidbit (1)

jazman_777 (44742) | about 12 years ago | (#4464817)

They _could_ make out the symbols "/." in a faint gray shade on this monster blackhole.

Big Black Holes are Thin (2, Interesting)

afreniere (611999) | about 12 years ago | (#4464819)

I think it was mentioned in "A Brief History of Time" by Stephen Hawking that black holes are actually less "dense" the larger they get. "Density" doesn't actually make a lot of sense here because there isn't really a material to have density, but if you take the mass and divide it by the volume denoted by the Schwarzchild Radius, you get decreasing density with increasing mass. Many have surmised, from this, that maybe the Universe is really a super-mega-humongo-unimaginably-massive black hole whose Schwarzchild radius is a few hundred billion light-years. We're not a singularity because, since we're *inside* the black hole, our time is dilated relative to the outside, and we haven't collapsed yet...

p.s. I may be wrong about which book mentioned it, but it was one of those uber-cool sci-fact books by a reputable physicist, like Feynman or something. Really. I'm serious.

-Ansel.

Several black hole questions ... (0)

Anonymous Coward | about 12 years ago | (#4464820)

I've been interested in black holes since my last relationship, and I have a few questions. First, could black holes eventually swallow all matter and will there be just one someday? Could such a single singularity explode, as in a big bang? Could this be where some of the missing matter is? How small can a black hole be, could we manufacture one? Since black holes accelerate outside mass to the speed of light, does that stuff freeze in time? Could you use that acceleration to get around? What happens to the stuff at the center, that is the stuff that isn't time locked?

2tec ~ just curious
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