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Largest Black Hole Measured
Posted by
kdawson
on Fri Jan 11, 2008 11:48 AM
from the that's-no-moon dept.
from the that's-no-moon dept.
porkpickle tips us to a BBC article on the quasar OJ287, a binary object containing largest black hole yet discovered, weighing in at 18 billion times the mass of Sol. Researchers were able to estimate its mass due to the presence of a smaller black hole in orbit around it. When the smaller companion's orbit intersects OJ287's accretion disk, once every 12 years, it triggers a burst of radiation that was detected by the Spitzer Space Telescope. More detail and a diagram are available on the Turku University site.
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eh? I don't get it? (Score:4, Interesting)
I mean, if they used the word "massive" I'd get it. But large?
Re:eh? I don't get it? (Score:5, Informative)
Parent
Re:eh? I don't get it? (Score:5, Informative)
Parent
Re:eh? I don't get it? (Score:5, Informative)
Furthermore, this thread is based on quibbling over semantics without really understanding what the author quite validly meant. The "black hole" aspect of a singularity is a description of the effects of its event horizon, which of course scales with mass. A more massive black hole is by definition larger then a less massive black hole. Someone mod this up so this misunderstanding can be cleared up for more people.
Parent
Re:eh? I don't get it? (Score:5, Informative)
Parent
500 AU event horizon (Score:2)
correction: 325 AU (Score:3, Funny)
Re:eh? I don't get it? (Score:5, Informative)
Parent
Re: (Score:3, Interesting)
Re: (Score:3, Informative)
I mean, if they used the word "massive" I'd get it. But large?
I believe they are measuring the event horizon, not the singularity.
Wow. (Score:5, Funny)
Proctologists across the globe swoon!
so is Rosie orbiting Oprah, or vice versa? (Score:2, Funny)
Ask slashdot (Score:5, Funny)
That was serious, here's the link [uncyclopedia.org] to the non-serious.More there...
Re:Ask slashdot (Score:5, Informative)
I think astronomers are reluctant to guess at a size limit now as they don't want another discovery to make them look like asses.
Parent
Re: (Score:3, Informative)
While I can't give you numbers since I'm going from memory, but there used to be a theoretical limit to black hole size.
There has never been a theoretical limit to the size of a generic black hole. (Technically, the observable universe could be in a giant black hole.) But back when people thought the only way a black hole could form was from the collapse of a single star, there was a practical limit on the size of an astrophysical black hole: if it forms from stellar collapse, it can't be more massive than the most massive stars. Everyone recognized that black holes can get larger by swallowing more mass, but it was a l
Re: (Score:3, Informative)
The Eddington limit [wikipedia.org] appears to limit the size of a star. At one point in time, it was thought that black holes formed from the collapse of stars. Later on, it was concluded that supermassive black holes are very good at feeding on neighboring stars, and thus supermassive black holes could form. The Wikipedia page on Black Hole Parameters [wikipedia.org] has an explanation.
When it comes to choosing neighbors, (Score:3, Funny)
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Not "hahaha man that was bad haha." just lame.
Ugh, the jokes aren't even funny anymore... (Score:2, Funny)
Need a better measurement comparison (Score:5, Funny)
Yes, but how many Twinkies is that?
Re:Need a better measurement comparison (Score:5, Funny)
Parent
Re:Need a better measurement comparison (Score:4, Funny)
-nB
Parent
Re: (Score:3, Insightful)
Or 3.685*10^29 AU, (3.24810^24 Parsecs), 1.05*10^25 light years, room for about a billion of these in the universe!
"That's a really big Twinkie"
9.8 × 10^50 twinkies (Score:2)
http://www.mctague.org/carl/fun/twinkie/ [mctague.org]
Mass of the Sun: 1.99 × 10^33 g
http://www.google.com/search?hl=en&q=mass+of+the+sun&btnG=Google+Search [google.com]
1 solar mass = 5.47 × 10^31 twinkies
9.8 × 10^42 twinkies (Score:2)
I'm glad it's Friday. *headdesk*
Re: (Score:2)
2*10^30*1.8*10^10=3.6*10^40
3.6*10^40*10^3= 3.6*10^43
3.6*10^43/35=1.028*10^42
Gravity & Levity together in a black-hole (Score:2)
which looks like a very light-bright sphere (maybe a little
physically distorted) to all humans, and within the absence of
light there is much levity to consider.
Tell me again, why is it a big black-hole and not a big bright-spot?
In the absence of levity there is gravity.
In the absence of gravity there is levity.
Tag as Sun!Sol (Score:3)
Re: (Score:3, Insightful)
gridwars (Score:3, Informative)
And again, and again...
Question about gravity (Score:5, Interesting)
Re: (Score:3, Interesting)
(In fact if the singularity somehow disappeared magically the outside world wouldn't detect it since the signal of black hole disappearing wouldn't escape from the gravitational well.)
Re:Question about gravity (Score:4, Informative)
Parent
Re: (Score:3, Insightful)
But the most commonly accepted theory is that heavy objects cause the fabric of spacetime to bend under its mass - like a heavy ball placed on rubber sheet.
With this image, it is spacetime that bends so there's no meaningful question for how gravity 'escapes' from it.
Re: (Score:3, Informative)
One hypothesis of gravity is that it is an exchange of 'gravitons'. If this hypothesis is indeed correct, then it does indeed make sense to ask how these gravitons can escape a black hole. And I don't know the answer to that.
Static gravitational fields are mediated by virtual gravitons, which can travel at any speed, including faster than light. However, you cannot use them to transmit information, i.e., changes in the field from inside the horizon.
With this image, it is spacetime that bends so there's no meaningful question for how gravity 'escapes' from it.
Right. Classically you can see that the exterior field does not depend on the interior field, and that gravitational radiation generated inside the hole can't get out.
Re: (Score:3, Interesting)
However, the mediating particles themselves are not affected by the force they mediate. Otherwise the universe would disappear up its own arse.
Hence, gravity is not affected by gravity.
Actually, most mediating particles are affected by the force they mediate, including gluons, the hypothetical gravitons, and IIRC the W bosons.
In gauge theory, a non-Abelian gauge group will in general lead to a nonlinear Yang-Mills theory with self-interacting fields, in contrast to the linear Abelian theory of electrodynamics.
Because gluons, the mediator of the strong nuclear force, themselves carry strong ("color") charge, it's possible for them to bind to each other. (See glueballs [wikipedia.org] in quantum chromody
Re: (Score:3, Informative)
If I used my magic obliterator to magically make the sun disappear, would Earth go flying off into space at the same moment or would it continue to orbit the missing sun for the 8 minutes it would take the last rays of light to reach us?
The latter.
This is where they say gravitons come in as a particle that conveys gravity which doesn't make any sense.
Why doesn't it make any sense? Photons are particles which convey electric and magnetic forces, do you have a problem with them too?
Anyway, you don't need to appeal to graviton particles to answer the above question. Even in classical general relativity, the answer is still "8 minutes later", since that's how long for gravitational waves of spacetime curvature, traveling at the speed of light, take to reach the Earth.
That's incredible! (Score:5, Informative)
For a 12 year orbital period this means that the orbiting black hole is AVERAGING 1/6c (~49965km/sec, call it 50k km/sec)... meaning at periquaserion it's really booking! Much faster than The Dash!
Tom.
And so... (Score:4, Funny)
I see they used the term "Sol" (Score:3, Funny)
Re: (Score:3, Informative)
Re:that's a lot (Score:5, Funny)
Parent
Re: (Score:3, Informative)
I'll save you all the time of googling this cuz I know you wanna know too. There's 200-400 billion stars in the milky way for example but most are bigger than our sun I think. So 18 billion solar masses is A LOT of stars to suck up in one galaxy. Geeze the think probably looks like a big donut by now.
Actually, my understanding is that the most common stars in the galaxy are Red Dwarfs, and thus smaller than our sun. (Yup, NASA confirms: http://planetquest.jpl.nasa.gov/glossary/red_dwarf.html [nasa.gov])
Re: (Score:2)
Well, I've read comments here over the years that prove the existence of Mass Holes.
Now I suppose we just find those users and weigh them.
Re: (Score:2, Informative)
The Hawking Evaporation or just random stuff that's falling into it (gas, particles) should emit a considerable amount of light. W
Re: (Score:3, Interesting)
Re:orbiting blackholes? (Score:5, Informative)
Furthermore, as the Earth-Sun barycenter is well outside the Sun's Schwarzschild radius, it would be outside the event horizon of a solar-mass black hole, too. Not that the location of the barycenter even matters to the stability of the orbit.
There are exoplanets — the first discovered, actually — known to orbit neutron stars, which are only 10-20 km in radius. There's no reason why planets couldn't orbit black holes too.
Parent
Re: (Score:3, Informative)
(FYI, the smallest known black hole candidates are about 3 solar masses, with a size of about 18 km in diameter, i.e., about half the size of a neutron star.)
Re: (Score:3, Interesting)
Re: (Score:3, Insightful)
"Today"?! How often do you feel the need to stare at a gaping anus?!?