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Black Hole at Center of Milky Way

michael posted about 13 years ago | from the frank-hayes-had-it-right dept.

Space 165

kwertii writes: "The Washington Post reports new evidence that there is a black hole with the mass of 2.6 million suns at the center of our galaxy. The Chandra X-Ray Observatory happened to be looking at the presumed site of the hole at the moment it absorbed a comet, blasting x-rays off into space as a byproduct. The implication is that the Milky Way is slowly spiraling down into a giant galactic drain..."

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fp (-1, Offtopic)

gavlil (255585) | about 13 years ago | (#2259105)

fp

Re:fp (-1, Offtopic)

Anonymous Coward | about 13 years ago | (#2259115)

What the hell does FP mean?

Re:fp (-1, Offtopic)

gavlil (255585) | about 13 years ago | (#2259147)

i tried to writ first post but the black hole sucked the irst ost in!!!

Re:fp (-1, Offtopic)

Anonymous Coward | about 13 years ago | (#2259284)

First gatse.ms [microsoft.com] post! Mr Bill sez : "I W1|| 0WN J00, 5UX0R5!"

..Its not really suprising.. (1)

tolan's my name (234431) | about 13 years ago | (#2259108)

This has been a pet belief of mine for some time, as it is hard to see how a galaxy could form and survive without a ridiculous amount of mass gathering at the center.

My question is what is the approximate size (diameter) of this black-hole and what is its density. I assume its not particuarly dense just particuarly big.

Re:..Its not really suprising.. (0)

olivieradam (162258) | about 13 years ago | (#2259151)

>>what is the approximate size (diameter) of this black-hole

Assume that it is a few kilometers (10) diameter large sphere, with a giant mass, extremely dense in deed, so we can orbit around with the help of gravitational laws (Newton). But I doubt that we fall in, as satellites like our moon don't fall at all. Satellites can raise nearer, but before they fall they come to Roche boundary and tear appart (Saturn belt).

Re:..Its not really suprising.. (1, Informative)

DodgyGeezer (83311) | about 13 years ago | (#2259205)

"My question is what is the approximate size (diameter) of this black-hole and what is its density. I assume its not particuarly dense just particuarly big."

This article from the BBC's web site is more informative: [bbc.co.uk]
http://news.bbc.co.uk/hi/english/sci/tech/newsid _1 526000/1526724.stm. It claims that the black hole is 150 million kms across.

Re:..Its not really suprising.. (2, Interesting)

Hater's Leaving, The (322238) | about 13 years ago | (#2259272)

According to the BBC article, the size is 108 times that of the diameter of the sun, and the mass is 2 million times the mass.
108^3=1.25 million
=> the density is 8/5 that of our own sun.

Anyone else think these figures sound like they've been pulled out of someone's arse? Or am I just a cynic?

THL

density of a black hole is infinite. (4, Interesting)

moller (82888) | about 13 years ago | (#2259408)

Or approximately infinite.

Density is defined as d = m/v (m is mass, v is volume.)

The volume of a singularity (the object at the center of a black hole) is effectively zero, so the density of the singularity is undefined (though commonly said to be infinite).

When the diameter of a black hole is referred to, they are most often talking about the Event Horizon, the boundary around the singularity from which nothing can escape, not even light.

Note that the distance of the event horizon from the singularity is determined by the mass of the black hole, not the density or volume (since density and volume for ALL singularities are effectively equal). Gravity is still dependent on mass, and the event horizon is simply the region of space where the escape velocity from the singularity's gravitational pull exceeds the speed of light.

(on a side note, since the only real requirement for a black hole is to have zero volume, anything could become a black hole if compressed enough.)

~Moller

Re:density of a black hole is infinite. (3, Interesting)

Dyolf Knip (165446) | about 13 years ago | (#2260270)

the only real requirement for a black hole is to have zero volume, anything could become a black hole if compressed enough

Indeed. Problem is, the smaller a black hole, the faster it evaporates due to Hawking radiation*. So while you could theoretically turn my cat into a black hole, neither he nor it will last very long (provided you do it somewhere far away from some mass is can eat up). And you'd owe me a new cat.

* Hawking radiation: he hypothesized that all the time all over the universe, pairs of virtual particles pop up. They are anti-particles to each other, so they annihilate each other as soon as they appear and nobody is the wiser. But, should a pair appear right on the event horizon, one particle gets sucked in and the other goes free and to balance the energy books, the black hole loses a very, very small amount of energy. Needless to say, it takes a while. This big monster of a hole will probably evaporate around 10^100 A.D.

Re:..Its not really suprising.. (2, Insightful)

tolan's my name (234431) | about 13 years ago | (#2259444)

They may have been, however a large [diameter] black-hole [and by that I just mean large diameter of event horizon] does not have to be very dense.

Basically if we take an object [well a sphere] of density d with a mass m then as we increase the diameter x [in a linear manner] the volume increases as x^3. So since g~m/x^2 the effective gravity on the perimeter increaes linearly.

In otherwords [in newtonian terms anyway] a large enougth object of any density would become a blackhole.

Interestingly as such an object would not necessarily be particuarly different from our world [ie if our universe is big enough and is evenly distributed etc then light is bounded, bounded universe ~ black-hole]

Re:..Its not really suprising.. (1)

Johnny5000 (451029) | about 13 years ago | (#2259368)

It doesnt seem dense from what I could tell.

The diameter of the sun is 862,400 miles.

The diameter of the black hole is about 93 million miles, which is about 107.8 times as large.

The volume of the black sun would be... lets see, 4/3 pi r^3, I believe.

about .3 million miles cubed, if my calculations are correct.

The black hole volume would be about 421,000 million miles cubed.

so the density would be about 4000 times as great as the sun, if I'm not mistaken.

Which I probably am.

-J5K

Re:..Its not really suprising.. (2)

Dyolf Knip (165446) | about 13 years ago | (#2260200)

Ok, if sphere A is twice as wide as sphere B, it's 2^3 = 8 times as big. If it's 107.8 times as wide, it's therefore 107.8^3 = 1252726 times as big. Volume is a third degree relationship.

If it's 2.6e6 times as massive, then its density is 2.6e6/1252726 = 2.08 times as dense.

But really, this is all moot. A black hole does not have density in any sense of the word. Its gravity is so large that it consumes itself and neatly exits the universe. It is a perfect geometric point, having mass but no volume, and since density = mass/volume, its density is a division by zero and requires a universal exception handler. The 93 million miles refers to the diameter of the event horizon, which is the point at which light itself can no longer escape.

Of course, nobody knows what it actually looks like inside the event horizon, so it's possible that the black hole consists of 2.6 million Solar masses worth of chocolate bars or something.

Re:..Its not really suprising.. (0)

Anonymous Coward | about 13 years ago | (#2260333)

Don't confuse black holes with the singularities inside them. Singularities are perfect geometric points; black holes are regions bounded by an event horizon that contain a singularity.

Big Slashdot Announcement @# +1 ; Important #@ (0)

Anonymous Coward | about 13 years ago | (#2259375)

Is Slashdot accepting donations to purchase a one-way ticket to the black hole for the uber cyber-geek wannabe Jon Katz?

Thank you and have a heroin-induced weekend.

Re:..Its not really suprising.. (1)

Matt Kimball (1226) | about 13 years ago | (#2259378)

My question is what is the approximate size (diameter) of this black-hole and what is its density. I assume its not particuarly dense just particuarly big.

Huh? It's a singularity, of course. You know, point-mass and all that, so it's very dense and very small.

But maybe you mean how far out is the event horizon? You can exactly calculate it from the mass of the black hole using R = 2 * G * M / c^2 where G is the gravitational constant, 6.67e-11, and c is the speed of light, 3e8. Since the Sun's mass is 1.989e30 kg, you can find this black holes mass by multiplying by 2.6e6. When I work out the radius of the event horizon, I get 7.7 million kilometers. From that you can calculate the "density" if you are still interested.

I bet you could have found all this out with this here Internet thing. After all, that's what it's here for.

Dude! It's a black hole (1)

Nino the Mind Boggle (10910) | about 13 years ago | (#2259703)

I always thought that a black hole, by definition, has infinite density, and zero diameter.

Now the size of it's event horizon is a different matter...

A black hole can be as dense as water (1)

MillionthMonkey (240664) | about 13 years ago | (#2260116)

The density can be calculated two ways. The real density is infinite (all the mass is at a point in the center)

Apparent density (which is the only density you can really calculate) varies proportionally to M/R^3 where M is mass and R is the radius from the center to event horizon. But with black holes, R is directly proportional to M (R=2GM/c^2). So this "density" falls off as 1/R^2 or 1/M^2 (take your pick). But this is not real density. Remember the "volume" is proportional to M^3. But this isn't the hole's own volume. It's the volume contained within its event horizon, which is much different.

The surface gravity at the event horizon can be arbitrarily low, because it varies INVERSELY with the mass of the hole: g=(c^4)/(4*G*M). A 2-million-sun black hole has a mass of 5.2x10^36 kg. I get a "surface gravity" (at the event horizon) of about 6000 g when I plug that in. (This is about 7.7 million km from the hole.) Which is pretty sad, actually. Surface gravity at the surface of a mere sun-sized black hole would be 2.6 million times greater than this. But you would have to get much closer to the smaller hole to reach its own event horizon. A small black hole's field falls off very quickly because the mass is comparatively small. A supermassive black hole, OTOH, has a relatively weak field that persists in strength for many light years outward.

For a black hole to have a surface gravity of about 1g, it would need to weigh as much as 16 billion stars (only a few percent of the mass of a typical galaxy). Such a hole would have a radius of 50 billion km (about 1/3 of the distance from the Sun to the Earth). The hole in M87 is only about half this size. Meaning that you would experience a surface gravity of 2g at the event horizon, and you would probably not even realize you fell in for several hours after wandering inside- unless you could look through your spaceship's window and see the weird optical effects on stars. By the time you would experience the "spaghettification" effect from tidal forces, you would almost be at the singularity anyway. A smaller hole can spaghettify you before you even cross the event horizon.

Minor nitpicking... (0, Redundant)

Vuarnet (207505) | about 13 years ago | (#2259109)

By a stroke of good fortune, NASA's Chandra X-ray Observatory satellite happened to be looking when the presumed black hole enjoyed a quick snack of gas and dust. Analysis of the resulting belch -- a sudden X-ray flare that changed in intensity over a span of just a few minutes -- provided strong new support for the existence of the black hole. So when did this gas and dust turn into a comet, exactly?

This hipothesis of a giant blach hole at the center of the galaxy is really interesting... too bad we won't have the galactic center exploding, as in Larry Niven's "Known Universe" books.

more nitpicking... (2)

radja (58949) | about 13 years ago | (#2259144)

>By a stroke of good fortune, NASA's Chandra X-ray Observatory satellite happened to be looking when the presumed black hole enjoyed a quick snack of gas and dust.

give or take a few million years... light does take a little while to reach us from the middle of the galaxy you know :)

//rdj

Re:more nitpicking... (0)

kiwipeso (467618) | about 13 years ago | (#2260095)

27 000 light years approximately?

Re:more nitpicking... (2)

Dyolf Knip (165446) | about 13 years ago | (#2260296)

30,000 years. Not a few million.

Re:Minor nitpicking... (2)

Guppy06 (410832) | about 13 years ago | (#2259236)

"This hipothesis of a giant blach hole at the center of the galaxy is really interesting... too bad we won't have the galactic center exploding, as in Larry Niven's "Known Universe" books."

You mean the center of the universe. And we can't look at the "center" of the universe all that easily because that would require pointing our telescpes in a direction that is perpendicular to everything.

Re:Minor nitpicking... (1)

haruharaharu (443975) | about 13 years ago | (#2259323)

no, he means the center of the galaxy. What are you thinking of?

Oh boy, that's a real sucker ! (0, Offtopic)

Taco Cowboy (5327) | about 13 years ago | (#2259110)



Talk about a gigantic sucker.

Oh boy !

Re:Oh boy, that's a real sucker ! (0)

Anonymous Coward | about 13 years ago | (#2260161)

Offtopic?

Who the fuck modded this? At least give it a 0, funny.

Haiku (3, Funny)

quintessent (197518) | about 13 years ago | (#2259116)

At the candy shop--
Dark, terrible, he requests:
"One Milky Way, please"

Re:Haiku (2)

geomcbay (263540) | about 13 years ago | (#2259775)

Offtopic? +5 Funny/Genius.

No fear, the galaxy's safe. (3, Insightful)

Jodrell (191685) | about 13 years ago | (#2259118)

A mass of 3 million Suns may seem a lot, but it isn't when you remember that the Galaxy is quite a bit bigger than that. It's unlikely that this Black Hole could "swallow" the galaxy, in fact it's probably the only reason our galaxy exists.

Incidentally, the BBC article is here [bbc.co.uk] .

Re:No fear, the galaxy's safe. (2, Informative)

gazbo (517111) | about 13 years ago | (#2259159)

Possibly due to the name, everybody seems to treat a black hole as if it is exactly that - a hole. Really it is just a massive gravity source due to phenomenal mass and density.

The implication in this case is that the black hole provides a central gravity source large enough that the entire galaxy slowly circles it, in a gradually degrading orbit. In this aspect you are right - without such an object the Milky Way could not exist as it does now, as there would be nothing stronger than the attraction between solar systems to hold it together.

However, that does not mean that the black hole is incapable of "swallowing" the galaxy. The fact that the Milky Way is a spiral demonstrates that the orbit is degrading. As more objects are drawn in to the black hole, it can only serve to increase the size and mass and make an even more powerful gravity well.

Re:No fear, the galaxy's safe. (2, Interesting)

CheshireCatCO (185193) | about 13 years ago | (#2259379)

n this aspect you are right - without such an object the Milky Way could not exist as it does now, as there would be nothing stronger than the attraction between solar systems to hold it together.

The attraction between stars would be quite enough to hold the galaxy together. For decades, galactic researchers didn't have any reason to think that there was a black hole at the center of our galaxy. They never needed it to hold things together; after all, the black holes looks just like 3 million solar mass stars in the galactic nucleus to our Sun.

By way of analogy, globular clusters are hold themselves together without black holes in their cores (N-body simulations indicate that they are, in fact, dynamically stable). And there is at least one case of a galaxy that probably does not have a black hole in its nucleas. All tests have come up negative for it.

The fact that the Milky Way is a spiral demonstrates that the orbit is degrading.

Not really, no. The spiral structure of galaxies has nothing to do with "spriralling down the hole." It's probably some time of density wave phenomenon, stable and self-perpetuating. The orbits of individual stars and gas clouds are basically stable, Keplerian orbits.

Re:No fear, the galaxy's safe. (2)

Dyolf Knip (165446) | about 13 years ago | (#2260329)

The orbits of individual stars and gas clouds are basically stable, Keplerian orbits

Yeah, really fscking long ones; plus they've got this vertical oscillation. I think Sol's orbit is 200 MYears and the oscillation is 26 MYears. It's thought there may be some correlation between mass extinctions here on earth and when we go through the thickest part of galaxy.

Re:No fear, the galaxy's safe. (1)

sportydan (519712) | about 13 years ago | (#2259416)

[quote]The fact that the Milky Way is a spiral demonstrates that the orbit is degrading[/quote] Spiral galaxies do not degrade, this was recently studied by someone who was looking to see how they stay together when it should be that the stars at the outside have to orbit much faster then the stars on the inside to keep the galaxy together, but it was observed that they do not. It was found that it stays together because the stars in the centre of the galaxy are not always the same. They all rotate in circles which bring stars at the outside near the middle, and the stars in the middle in turn rotate so that they go to the outside. So the orbital circumfrance of all the stars is close to being the same and the galaxy stays together. dan.

Re:No fear, the galaxy's safe. (2, Informative)

Neil Rubin (11261) | about 13 years ago | (#2259971)

However, that does not mean that the black hole is incapable of "swallowing" the galaxy. The fact that the Milky Way is a spiral demonstrates that the orbit is degrading. As more objects are drawn in to the black hole, it can only serve to increase the size and mass and make an even more powerful gravity well.

Actually, it is impossible to for a black hole to ever swallow all of the matter orbiting it, unless some outside force (not gravity) starts literally pushing it in. This is a simple consequence of the conservation of energy.

For any object in a bound orbit in a gravitation field with a 1/r^2 force (true for a black hole except when you get extremely close), the average kinetic energy of the orbit <T> and the average potential energy <U> obey <U> = -2 <T>. This is due to the famous Virial Theorem. As a result, the average total energy is always negative and equal to half of the average potential energy.

Now, as the average radius of an orbit decreases, the potential energy will become more negative, and so will the total energy. If this were to happen to all of the matter orbiting the black hole, the total energy of the system would decrease--impossible!

What actually happens is that the particles in orbit constantly bounce off each other, some gaining energy and some losing. Those that lose enough, fall into the black hole. Those that gain enough, escape never to be seen again.

This is exactly what is observed to happen with the clouds of dust that collect to form stars. It all bounces around, and some of it ends up in the star while the rest of it flies off into the great beyond. Of course, some of the extra energy in the black hole case is lost from the X-rays originating from the extremely hot region just outside the horizon. That, however, can't explain how something the size of a galaxy could all end up that close to the horizon of the black hole to begin with. A very large fraction of the matter must escape long before then.

Better than the BBC. (0)

Anonymous Coward | about 13 years ago | (#2259161)

What's really funny is the Washington Post got scooped by slashdot, check the science section, and Fox News! That's right. When excited matter from the wrong side of the accretion disk attacks. It's a shame we won't see primary researchers on Paula Zahn with counterpoint by Pat Robertson.

Re:No fear, the galaxy's safe. (3, Informative)

Cheeko (165493) | about 13 years ago | (#2259385)

actually the black hole will continue to grow as it swallows more matter. That is to say that the event horizon will continue to expand. This is the result of the increase in gravity as it becomes denser and denser. In effect it swallows some matter, expands, thus making it stronger and able to swallow more matter, and so on. In theory as long as there is matter flowing into the black hole then it could continue expanding to swallow the whole galaxy in time.

Steven Hawking explains this concept pretty well in his Brief History of Time

Re:No fear, the galaxy's safe. (1)

CheshireCatCO (185193) | about 13 years ago | (#2259525)

A black hole can only consume as much matter as it can reach. Its gravity doesn't have some magical proerpty that allows it to yank stars out of their orbits, so the feeding slows to a near halt after a while. This is why the Milky Way does not poesses an active nucleus like many younger, distance galaxies appear to.

Re:No fear, the galaxy's safe. (1)

Cheeko (165493) | about 13 years ago | (#2260157)

I'm not saying that it does have magical properties, but as the comet proves, the black hole is still eating matter. Its just a matter of time (say a few hundred million years or soemthing) until its mass increases to a point that maybe the closest star starts to get slowly pulled in.

I will admit though that the fact that the force of gravity drops off rather quickly over distance makes if likely that it would take ALOT of mass to make the black hole expand to swallow the whole galazy.

Re:No fear, the galaxy's safe. (1)

theDunedan (462687) | about 13 years ago | (#2260375)

As I try to imagine what is going on, I imagine
that by now the area in the vicinity of the black
hole is stable. With most everything orbiting
the black hole, not much drops in. So it is not
surprising that the area is not highly luminous.

What causes the luminosity spikes then? Perhaps
it is when two objects near miss each other,
throwing one of the objects into an orbit which
then gets eaten by the black hole.

sevneth psot! (-1, Offtopic)

Anonymous Coward | about 13 years ago | (#2259120)

ACs Rule!!!
Suckaz!

The milkiyway may have a black hole... (1, Redundant)

smaughster (227985) | about 13 years ago | (#2259122)

But we've got CowboyNeal!

I wonder if these effects will cancel each other

Other links (4, Informative)

Joao (155665) | about 13 years ago | (#2259123)

Here are a few more links on this:

Official website [harvard.edu]

Official press release [harvard.edu]

Story on CNN [cnn.com]

Whe are doomed (0, Troll)

ruisantos (316753) | about 13 years ago | (#2259124)

Doommed I tell you !!!!

Vindicated at last (2, Funny)

Rogerborg (306625) | about 13 years ago | (#2259128)

  • The implication is that the Milky Way is slowly spiraling down into a giant galactic drain...

They all laughed when I built my Y2k bunker and bought all that Spam(tm). Well, who's laughing now?

Re:Vindicated at last (1)

buttahead (266220) | about 13 years ago | (#2260135)

I'm laughing now. The image of you and the spam in question being compressed by the gravity of 2.6 million suns -- finaly turning into some carbon based spam patty -- is a funny one.

-tom

Shouln't this exact moment not last for ever?? (3, Insightful)

Deag (250823) | about 13 years ago | (#2259139)

I'm probably completely wrong here, but as you go near a black hole doesn't time not slow down, so to us this comet going into hole should last forever... or something???

Can't wait for Celine Dion single (1)

Kibo (256105) | about 13 years ago | (#2259154)

They're talking about a clump of matter in the accretion disk that isn't quite ready to go down. But yes, we would never see the moment the clump actually crossed the event horizion. We would get to see it get closer and closer to the event horizon at lower and lower frequencies, but never cross.

Re:Shouln't this exact moment not last for ever?? (0)

Anonymous Coward | about 13 years ago | (#2259155)

What do you think we are Einstien or something?

Re:Shouln't this exact moment not last for ever?? (3, Informative)

krlynch (158571) | about 13 years ago | (#2260364)

You are correct ... and you are also wrong.

Let me explain :-)

To an observer outside the event horizon of the black hole, the object never appears to actually cross the horizon, just to approach it more and more slowly as time goes on. In other words, the clock of an infalling observer will appear to run slower than the clock of an observer that does not approach the horizon. More generally, to a distant observer a clock in a strong gravity field will run slower than a clock he carries around with him.

Meanwhile, for the poor observer entering the black hole, as he approaches the horizon, the clock HE carries appears to continue ticking away at its usual rate, while his view of the universe slowly gets distorted, so that it looks like he is travelling down a tunnel towards the hole's surface. In a finite amount of time, he crosses the event horizon, and the "tunnel vision" he has of the rest of the universe shrinks to zero size. He doesn't notice his clock slowing down, and he eventually will hit the "bottom" of the hole.

Interesting fact: if he tries to fight the hole to prolong the time before he hits the bottom, he'll actually hit the bottom sooner than if he didn't fight.... of course, when you've already been ripped apart by the tidal forces, you wouldn't notice, but let's consider just and "ideal observer" :-)

This "strange" (some would incorrectly say "paradoxical") behavior of the same set of events appearing differently to two observers is one of the hallmarks of the "Theory of Relativity" ... but results like this where two people disagree qualitatively on the outcome can only occur when the two can never again communicate with each other. Otherwise, they will only disagree quantitatively on the outcome of an "experiment".

Just Wondering (0)

Anonymous Coward | about 13 years ago | (#2259140)

If, as the article states, nothing can escape the black hole, then how is radiation emitted?

Re:Just Wondering (1)

deathcow (455995) | about 13 years ago | (#2259148)

Nothing is seen past the event horizon of a black hole. Beyond that, there are great masses of rotating gasses becoming enormously compressed orbiting their way around and falling in towards the black hole. These massively compressed gasses, dust, etc. get so incredibly hot that unfathomable amounts of energy are released well outside the event horizon. This energy can escape and be seen.

Re:Just Wondering (1)

mike77 (519751) | about 13 years ago | (#2260248)

Hey, I saw some things on here which aren't entirely correct, I just wanna set the record straight.... no evil intentions or attempt to anger anyone is being made.

1)Nothing is seen past the event horizon of a black hole. Beyond that, there are great masses of rotating gasses becoming enormously compressed orbiting their way around and falling in towards the black hole. These massively compressed gasses, dust, etc. get so incredibly hot that unfathomable amounts of energy are released well outside the event horizon. This energy can escape and be seen.

-> Once something (gas, dust, small planets, etc) has passed the event horizon you will see nothing from it. The idea of the event Horizon is that at that point the escape velocity is the speed of light. As matter cannot reach this (thank Einstein) once it passes, it's gone. this also works for light, the speed of light is constant, once it passes the event horizon, it ain't coming back either. what we see from Chandra is photons(X-rays) that have been released PRIOR to some chunk of mass passing the event horizon.

2)Does anybody here know about the work that is being done on gravity waves?

-> try checking out LIGO (Gravity wave observatory just now coming online)
http://www.ligo.caltech.edu/

3)I assume its not particuarly dense just particuarly big.

-> Black holes are by nature very dense. They have vary large amounts of mass stuffed into very small areas. For instance a small blackhole usually consists of several times the mass of the sun stuffed into an area of roughly the size of New York city.

4)is it 'draining' clockwise or counter-clockwise?

-> depends from which side of the galaxy you look at it...from above or below? ;)

Re:Just Wondering (0)

Anonymous Coward | about 13 years ago | (#2259150)

The Heisenberg principle makes it possible for energy (radiation or particles) to escape at the event horizon. Two particles are created from the energy exactly at the event horizon. One of them resides just outside the horizon and the other one is inside the no-escape zone. As a result, the former particle can escape while the latter one remains trapped in the hole. This is how the black holes radiate energy.

Feeding the mozillaquest troll... (2, Funny)

simpleguy (5686) | about 13 years ago | (#2259141)

" The implication is that the Milky Way is slowly spiraling down into a giant galactic drain... "

Do we get to see Mozilla 1.0 before that happens ?

Heh.

You mean.... (0)

Anonymous Coward | about 13 years ago | (#2259143)

"The funniest joke ever is that you're all going to be sucked into a black hole." Signed, God.

Ross Perot was right! (1)

Luxury P. Yacht (18865) | about 13 years ago | (#2259149)

Apparently he did hear a giant sucking sound!

Good! (-1)

stinkgeek.com (450152) | about 13 years ago | (#2259152)

It confirms what I always believed deep down, that the universe is just a huge pile of rubbish, about to be sucked up by a humongous Hoover.

This explains a lot why bad things are the default state of the universe, it's made out of plain dirt. As we humans are too.

I wish though, to learn who the housemaid is who is doing the hoovering? God (usually depicted as a black female, like many housemaids are) or fate/chance?

Does she play with dice (like Hawking believes) or not (like the revered Einstein believed)

I thought nothing escaped a black hole (1)

lyberth (319170) | about 13 years ago | (#2259153)

I was certain that absolutly nothing could escape a black hole, so im wondering how x-rays could be seen as a result.

of course my elementary school astronomy level excuses for that knowledge

Re:I thought nothing escaped a black hole (1)

germinatoras (465782) | about 13 years ago | (#2259203)

I am wondering the same thing. Here's what's really got me thinking:

As it turns out, the region in question could not be much larger than the diameter of Earth's orbit around the sun, or about 20 times the size of the hole's event horizon.

It seems like the emissions come from a region somewhere outside the black hole's event horizon, thus we're able to see them. But IANAS - anyone with more insight willing to post?

Re:I thought nothing escaped a black hole (0)

Anonymous Coward | about 13 years ago | (#2259708)

The x-rays aren't emitted after the matter is within the event horizon, but before. While the matter is accelerating towards the event horizon it's matter approaches the speed of light, and emits X-rays. The X-rays are fast enough to escape the gravity as long as they're outside of the event horizon.

Re:I thought nothing escaped a black hole (0)

Anonymous Coward | about 13 years ago | (#2259209)

The X-rays are emitted just before a particle has
passed the event horizon. It is possible to
escape from outside the event horizon, therefore
the definition.

Re:I thought nothing escaped a black hole (0)

kiwipeso (467618) | about 13 years ago | (#2260132)

X- rays are emittted because there is a matter/antimatter reaction on the event horizon.
The reaction creates radiation.

Not necessarily spiralling into it (4, Interesting)

1984 (56406) | about 13 years ago | (#2259156)

I saw a BBC "Horizon" about this the other day on a flight. They talked a lot about "feeding" of apparent suppermassive black holes that they think live in (probably all) galactic centres.

Apparently they stop "feeding" after a while because the mass of the surounding matter in the galaxy means it won't fall in. The attraction from the black hole is balanced, so the matter orbits the hole. Anything itinerant -- like a comet say -- that passed near the hole slowly or closely enough would still get swallowed, but most of the galaxy should stay intact.

Of course, that's iff nothing else intereferes. The Andromeda Galaxy is heading our way, so in some (distant) future time matter in it will become a significant gravitational influence on matter in our own Milky Way. That should upset the balance, and researchers are hypothesising the disruption setting off feeding of the black holes at the centre of both galaxies, which will go on to swallow up large portions of each galaxy.

Should be quite a show.

does not matter ;) (1)

mbyte (65875) | about 13 years ago | (#2259160)

Bah ... just launch 40 nova bombs into it and we are save again ;)

Dense? (1)

deathcow (455995) | about 13 years ago | (#2259164)

> I assume its not particuarly dense just

> particuarly big.


I guarentee it, sonny. That thing is dense. Reeeeally damned dense. It's downright doubly damned dense. I bet billions of pounds of gas and dust are probably being sucked past it's event horizon for every character I write. You should never play down a black hole sitting at the middle of a galaxy 100,000 light years across with possibly 1 trillion stars in it.


Probably though it is not as dense as someone who assumes a black hole isn't.

black hole information (1)

archen (447353) | about 13 years ago | (#2259189)

For any developers out there that want to see what this is really capable of you've got to check out http://www.square1.nl, these guys have put together a really nice gallery.

I grabbed a GoLive license as soon as I saw this stuff!

black hole discovered on internet (0)

Anonymous Coward | about 13 years ago | (#2259211)

see? slashdot could go off (&/or stay off) at ANY time. looks like the "new" "culture" is trying to trap itself. 'coarse, finding a venue as populated, & as uncensored/unmanipulated (at the same time) as here, is NOT possible. three cheers to the commander, for not sucking up. have you seen these guise [opensourcenews.com] ?

Interesting Photgraphic evidence of this... (1)

jcapell (144056) | about 13 years ago | (#2259212)

This is nothing new. I've had this photo for a while: Black Hole at the center of the Milky Way [3477457840] .

is /. working again? (-1, Troll)

Anonymous Coward | about 13 years ago | (#2259214)

this is a test.

which way (2, Funny)

Hooya (518216) | about 13 years ago | (#2259237)

is it 'draining' clockwise or counter-clockwise?

Were all gonna die!!!! (0)

Atrophis (103390) | about 13 years ago | (#2259247)

.... in like a 100 million years..

remember spaceballs? (1)

Hooya (518216) | about 13 years ago | (#2259254)

can we switch from 'suck' to 'blow'?

Yay! Chandra Found!!! (0)

Anonymous Coward | about 13 years ago | (#2259277)

(a back hole)

Required (1)

riggwelter (84180) | about 13 years ago | (#2259292)

My understanding for quite some time had been that current theory was that there was a super-massive black hole at the centre of every galaxy, and in fact that they were required for the formation of galaxies...

drain... (1)

h4x0r-3l337 (219532) | about 13 years ago | (#2259318)

The implication is that the Milky Way is slowly spiraling down into a giant galactic drain...

That's not at all the implication, and the article doesn't say that either. It would be nice if the slashdot editors didn't repeat everything that was submitted literally, since in this particular case, the bit about the "giant galactic drain", is simply bullshit, and obviously the brainfart of someone who doesn't know the least bit about black holes, gravity and orbits.

The Real Story is that they found Sha Ka Ree (3, Funny)

jea6 (117959) | about 13 years ago | (#2259347)

SYBOK Our destination is the planet Sha Ka Ree, which lies beyond the Great Barrier at the center of the galaxy.
KIRK (alarmed) The center of the galaxy?
SPOCK There Sha Ka Ree is fabled to exist.
KIRK But the center of the galaxy can't be reached. No ship has ever gone into the Great Barrier. No probe has ever returned.
SPOCK Sybok possessed the keenest intellect I have ever known.
KIRK Spock! My only concern is getting the ship back. When that's done and Sybok is in here then you can debate Sha Ka Ree until you're green in the face. Until then, you're either with me or you're not.
SPOCK (as if it's obvious) I am here, Captain.

News for nerds, indeed.

Re:The Real Story is that they found Sha Ka Ree (0)

MrHyd3 (19709) | about 13 years ago | (#2259866)

KIRK : There's ....something...out...there..(head turn)...off the wing.... SPOCK : You're presumption is correct, Captain (looking stiff) KIRK : It's .....still...out there.. BlackHole : Brrrrrrrrrrrrrrr (sound from Motion Picture everytime it shows the blue cloud) Bones : Dammit, Jim qit saying that. KIRK : We're....gonna......die SPOCK : Affirmative (Eyebrow raises) BlackHole : Suck, Suck Suck, Enterprise Z is gone.

Re:I suppose Earth is spiralling into the Sun? (1)

sgups (449689) | about 13 years ago | (#2259364)

Correct me if I am wrong but isnt a black hole a 'dead' star, while the sun is yet 'alive' and all the black hole effects are seen only when the star runs outs of its fuel?

My question is can a black hole grow infinitely?

Galactic flush... (1)

tcc (140386) | about 13 years ago | (#2259369)

This gives a new meaning to "FLUSH".

Now I wonder if it's clockwise or counter-clockwise :)

Re:Galactic flush... (0)

Anonymous Coward | about 13 years ago | (#2259657)

It's both. Which direction are you looking from?

gravity waves (1)

iAlex (134189) | about 13 years ago | (#2259402)

Does anybody here know about the work that is being done on gravity waves? I remember going to a seminar in college where Kip Thorn, a physicist out of Berkley I believe, spoke about his theory of gravity waves. I think these were small ripples in space-time that were supposed to be caused by black holes. The idea was that if they could be measured then it would prove the existance of black holes. I don't remember the particulars, I just went because it gave me extra credit for my Differential Equations class. But it seems that this work is now superseeded by these images from the observatory.

Re:gravity waves (0)

Anonymous Coward | about 13 years ago | (#2260380)

People aren't interested in gravitational waves just to prove the existence of black holes. Most everyone is already convinced they exist. Gravitational waves are interesting because they can tell us a lot more about how black holes behave than we can tell from electromagnetic observations.

Einstein was wrong. (0)

Anonymous Coward | about 13 years ago | (#2259423)

You can break the speed of light, by immersing yourself in a containment field, and then modulating that field the frequency of light.

Granted, there will be some time distortion. This is the same theory, that would let you walk through walls, by modulating your personal frequency to that of your environment. You just need to figure out some way to keep your molecules together during the modulation....

Re:confused...what's the frequency, Kenneth? (1)

LMCBoy (185365) | about 13 years ago | (#2260128)

What do you mean by "frequency of light"? Light can have any frequency, just about.


And what do you mean by "modulating your personal frequency"? What frequency is my personal frequency? Do I have to register it with the FCC? :)


Perhaps you mean the effective frequency associated with all matter particles, due to the wave/particle duality of matter? Which of the billions of particles that make up my material self shall I choose to represent my "personal" frequency? That frequency can't be modulated, however, so I don't know what you mean...

Say hi to Nigel Walmsley... (2)

dpilot (134227) | about 13 years ago | (#2259434)

when you get to the Wedge.

I've heard before that galaxies don't rotate right, that the core and outer velocities are not "correct" with respect to each other. This has been mostly in connection with dark matter and missing mass. I wonder how supermassive black holes affect this apparent mismatch. (for better, or worse)

Re:Say hi to Nigel Walmsley... (1)

niall2 (192734) | about 13 years ago | (#2259683)

The mass of the super massive black holes in galaxies is accounted for in the "missing mass" problem. The problem is that when the mass density of a galaxy starts to fall off (e.g. you start running out of galaxy), the velocity of the orbits at that radius should start getting smaller the further out you go. An orbits velocity measures the mass of everything within the orbit. In the real world, you never see this even when you run out of luminous objects in the galaxy. Hence the term "dark matter".

Care and feeding of black holes (2)

hodeleri (89647) | about 13 years ago | (#2259474)

From my understanding, a black hole will dissipate energy in the form of gamma/X-rays throughout its life. If the hole is not actively 'feeding' it will eventually dissipate (conservation of energy and all that). (I doubt a hole the size of this one will dissipate in any reasonable amount of time though.)

Of course, this is from my reading of Earth by David Brin, so I may be totally off kilter.

Re:Care and feeding of black holes (1)

Graymalkin (13732) | about 13 years ago | (#2259756)

Where do you get that a black holewill dissipate if it isn't eating up new matter? It is collapsed matter, it won't just disappear if given enough time. Besides the singularities themselves don't give off x-rays and gamma rays (nothing gets past the event horizon) it is matter accelerating towards the "surface" of the hole at crazy fast deltas and being stretched nearly infinitely by the tidal forces that emits said radiation. I just moved so I don't know what box my old cosmology notes are in but if you're interested I can find the equations that demonstrate all this.

Re:Care and feeding of black holes (1)

KyleJ61782 (106226) | about 13 years ago | (#2260022)

While it's true that they don't give off x-rays and gamma rays, due to the Heisenberg Uncertainty Principle, the fabric of space-time has particles and their corresponding anti-particles pop into and out of existence (mostly due to the vacuum energy of space). So, if one of these pairs happens to occur right on the event horizon, one particle could effectively be shot out away from it, while the other particle would fall into the hole. However, that particle shot into the hole, would in turn annihilate with some matter in the black hole, thus depleting the black hole of mass and thereby following the law of conservation of mass-energy.

Re:Care and feeding of black holes (1)

Neil Rubin (11261) | about 13 years ago | (#2259781)

I assume that you are referring to Hawking radiation. This, if it exists, would cause the black hole to dissipate. However, its typical wavelength is of the order of the radius of the black hole. A one million solar mass black hole has a radius of around one light-year, so the radiation is of extremely long wavelength and thus low energy. It is definitely not gamma or X-ray radiation.

The famous X-ray radiation believed to come from black holes actually comes from material outside the black hole, as it reaches incredibly high temperatures just outside the horizon.

Incidentally, the life-time of a black hole losing mass to Hawking radiation goes as the mass of the black hole cubed. A one million solar mass black hole is extremely long lived. That said, they may actually live forever, since no one has ever observed Hawking radiation (how could one observe such low energy radiation?), and I tend to doubt it actually exists. The reasons have to do with arcane details of Hawking's "proof."

Re:Care and feeding of black holes (3, Funny)

quintessent (197518) | about 13 years ago | (#2259889)

Whew! I was starting to worry that Slashdot's servers had been sucked in. Good to have you back, Slashdot.

this is news to you? (1)

cowtamer (311087) | about 13 years ago | (#2259487)

Beowulf Schaeffer has known this for a while :)

Now all we have to do is follow the puppeteers out of here

its not a comet (1)

Lawrence_Bird (67278) | about 13 years ago | (#2259798)

read the story before submitting your post - just because it says 'comet sized' does not mean it was a comet.

WoW!!!! (1)

snwbd4life (517179) | about 13 years ago | (#2259903)

Awesome!!!!!

chandra X-ray observatory... (1)

dollargonzo (519030) | about 13 years ago | (#2260103)

maybe the chandra x-ray observatory will find chandra levy in that black hole too...:-\

Chandra Levy? (0)

Anonymous Coward | about 13 years ago | (#2260137)

So THAT'S what happened to Chandra Levy!

Can't all go down the drain (2)

Michael Woodhams (112247) | about 13 years ago | (#2260190)

Only stuff that goes very close to the center of the galaxy can get sucked into the black hole - i.e. only matter with a very low angular momentum (relative to galactic center.) The total angular momentum of the system is conserved, so there is only so much you can feed the hole before you 'run out' of 'low angular momentum'. This is a likely reason why such black holes cause quasars in young galaxies, but they aren't being fed fast enough to do this in older galaxies.

I expect that if you could let the galaxy run for long enough (ignoring collisions with Andromeda, exhaustion of fuel for stars, proton decay, evaporation of black holes etc.) you would end up with some fraction of the mass eaten by the hole and the rest in circular orbits in a flat disk - as this is the minumum energy configuration for a given amount of angular momentum.

Actually, if you're prepared to wait a really long time, the angular momentum will be shed by gravitational radiation and the black hole wins after all. (Or would, if it hasn't evaporated.)

Who cares? (1)

evilninja (261516) | about 13 years ago | (#2260358)

This happened 27,000 years ago.

A small piece of basic physics (5, Informative)

PD (9577) | about 13 years ago | (#2260406)

I've noticed that some people have a bit of confusion here about exactly what the effects of a black hole are. Here's are examples:

Q: What would happen to the orbit of the earth if all the matter in the sun were suddenly compacted into a black hole?

A: Absolutely nothing. A black hole which contains the mass of the sun would still also have the same gravity as the sun. The earth would continue to orbit as it always has.

Q: The galaxies stars orbit around the black hole.

A: This isn't proven. Some galaxies don't have any evidence of a black hole, yet theirorbit around a center of mass. In any case, the black hole at the center of our galaxy is 2.6million solar masses. This is NOTHING compared to the billions of stars in the galaxy, so the effect of the black hole of the actual shape and orbit of the stars is not significant.

Q: Doesn't it sound like someone has pulled the stats on this black hole out of their arse?

A: Not really, the size of this black hole has been measured in several ways, including observing very high velocity stars near the black hole. The motion of these stars betrays the existence and size of the massive object at the galaxy's center.

Q: Aren't black holes required for the formation of galaxies?

A: We don't know for sure yet. There are galaxies without black holes, so it might not be required. Of course, we might just not be detecting the black holes that are in those galaxies.

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