Black Holes May Not Grow Beyond Certain Limit

xyz writes "Do black holes increase in size indefinitely? According to an analysis by astronomers at Yale and the European Southern Observatory, the maximum size a black hole may reach is only few tens of billion of solar masses. The limit was calculated using an analysis of what may happen to the gas surrounding a black hole which has reached few tens of billions of solar masses. It is thought that black holes of such size heat the surrounding gas to a temperature where the radiation pressure begins blowing outer layers into space."

Comments

Interesting repercussions

[AKAImBatman]

I am not an astrophysicist (IANAAP?), but this would seem to have some interesting implications for galactic mechanics. For one, does this means that stars are continously recycled by the black hole believed to be at the center of each galaxy? i.e. They get sucked in, crushed, then ejected as gassous emmisions which then collect and reform as a new star.

Wouldn't this also create a "galactic wind" similar to the solar wind experienced inside a solar system? Could such a wind (as weak as it may be on a micro scale) be responsible for the universe's apparent anti-gravity effect? It seems to me that if a galactic wind did exist, it would cause the galaxies to repel each other as the particles communicate back the forces of the particle collisions over billions of years.

Speaking of Black Holes, I was just listening to an interview with Brian Greene on NPR this morning. It seems that he has released a children's book designed to help children understand Relativity. Specifically, the link between gravity and time. Amazon has a nice video* where Mr. Greene explains the story and how he attempts to create an emotional connection between readers and the physics of Relativity.

* Full Disclosure: I did NOT include a referral code. This is a clean link
** Someone should really make a joke out of LHC doomsday and how we're all saved. I couldn't come up with anything funny.

Re:Interesting repercussions

[Ethanol-fueled]

They get sucked in, crushed, then ejected as gassous emmisions which then collect and reform as a new star.

That sounds a lot like the big bounce theory, which is like the big bang except that the bounces are periodic. It depends on the theory that space begins to behave repulsively as the amount of mass packed into it reaches a critical point.

Side note: makes much more sense then the big bang theory, which reeks of creationism.

Re:Interesting repercussions

[Zenaku]

I'm not an astrophysicist either, but as far as I can tell nothing about this hypothesis contradicts the idea that once matter crosses the event horizon it doesn't come out again, except as radiation. They aren't saying that the black hole begins "ejecting" gas, just that at that mass it gives off enough radiation to prevent any more gas from falling in.

I'm not sure I buy that as setting an upper limit on the size of a black hole. It just means the rate of growth would slow, and potentially reach equilibrium with regards to the surrounding gas. If something denser, like a star were to fall in, I doubt that the radiation pressure would push it away.

But who knows. I don't.

Re:Interesting repercussions

[jbeaupre]

Not quite sucking them in and spitting them out. Rather it's when the inflowing matter creates so much heat it clears out all the remaining matter in the area. Creates a "dry galaxy" (their term, not mine). So nothing left nearby for it to suck in and thereby grow.

An analogy would be how when a star forms it coalesces to a point that it produces enough energy to clear the area (T Tauri wind?). The star growth is then capped.

Re:Interesting repercussions

[KillerBob]

Side note: makes much more sense then the big bang theory, which reeks of creationism.

Until somebody asks where it all came from in the first place. Then you're back at square one, with the same problem that the Big Bang theory has.

Unless you adopt the Hindu/Buddhist take on the cosmology... it wasn't created, it didn't magically poof into existence out of nothing: it just is. Always has been, always will be, and goes through periodic cycles of growth and destruction, without end.

Re:Interesting repercussions

[mfh]

For one, does this means that stars are continously recycled by the black hole believed to be at the center of each galaxy? i.e. They get sucked in, crushed, then ejected as gassous emmisions which then collect and reform as a new star.

Well it could mean they are continuously recycled, and then ejected as gaseous emissions, but only if a spell-check was involved. :P

Either way, this SPELLS trouble for us all because it could potentially support arguments against the big bang. :S

Re:Interesting repercussions

[Colonel Korn]

I'm not an astrophysicist either, but as far as I can tell nothing about this hypothesis contradicts the idea that once matter crosses the event horizon it doesn't come out again, except as radiation. They aren't saying that the black hole begins "ejecting" gas, just that at that mass it gives off enough radiation to prevent any more gas from falling in.

I'm not sure I buy that as setting an upper limit on the size of a black hole. It just means the rate of growth would slow, and potentially reach equilibrium with regards to the surrounding gas. If something denser, like a star were to fall in, I doubt that the radiation pressure would push it away.

But who knows. I don't.

You are completely correct. Good work.

Re:Interesting repercussions

[Ethanol-fueled]

Unless you adopt the Hindu/Buddhist take on the cosmology... it wasn't created, it didn't magically poof into existence out of nothing: it just is. Always has been, always will be, and goes through periodic cycles of growth and destruction, without end.

...and that's the explanation which makes the most sense to me. I like science to be mundane and predictable. If I want drama then I'll go see a movie and entertain the thought of some big magical guy in a toga who made the Earth with snot and space rocks.

Re:Interesting repercussions

[sanosuke001]

Well, if you think of it as time being a loop, then there is no time outside of time (er...) and once it ends, it is back at the beginning again and starts over.

Now, ask me to prove that and I'll just laugh. But, there are possible outcomes/beginnings that might be plausible. I think time being a loop is a lot more realistic than some twat in the sky creating us, but that's my opinion.

Re:Interesting repercussions

[Bemopolis]

or one, does this means that stars are continously recycled by the black hole believed to be at the center of each galaxy? i.e. They get sucked in, crushed, then ejected as gassous emmisions which then collect and reform as a new star.

What happens, roughly, is that stars that stray too close to the black hole are torn apart by the tidal forces, their constituent gas adding to a large torus of gas orbiting the black hole. Some fraction of this torus loses enough angular momentum to either fall into the event horizon of the black hole, lost "forever" (astronomically speaking), or a grazing collision that gives it enough energy to avoid being sucked in. This gas can form a galactic wind of sorts: that flow becomes collimated by the high spin rate of the black hole and the torus of gas around it. This produces jets like those seen emanating from the core of M87. That gas, with its high temperature and flow rate, will not cool to a low enough temperature to coalesce into new stars any time "soon" (astronomically speaking.)

Now, there are flows that involve gas being ejected from the disk of the galaxy with less energy, which can rain back down onto the disk and contribute to newly-formed stars. But these "champagne flows" are usully caused not by the energetics of the central black holes, but rather the collective stellar winds from the stars in the disk; for example, the galactic superwind of M82

In both cases, the thermal energy of the ejecta is insufficient to explain the gravitational anomalies you mention.

Re:Interesting repercussions

[Mr. McGibby]

Side note: makes much more sense then the big bang theory, which reeks of creationism.

So, instead of using rational thought and evidence to decide what theory is correct, you're going to use your "gut" feeling to make the determination? Sounds a little like what the relgionists, that you're so quick to deride, like to do.

Re:Interesting repercussions

[SBacks]

Why does everyone assume that nothingness is the default? From everything we've observed of the universe, it tends towards chaos and disorder (entropy). Nothingness is the complete lack of entropy, so why would should that be considered stable?

And, by the way, there are branches of cosmology that contend that the universe, has, in fact, always been and will always be. It comes from the idea that as you measure time further and further backwards, you find yourself measuring time forwards again. It has something to do with string theory, but the math is way beyond me.

Re:Interesting repercussions

[Anonymous Coward]

I'm not an astrophysicist as well. Just thought you'd like to know.

Re:Interesting repercussions

[sexconker]

Don't feel bad, the physics is way beyond the string theorists, so they just make up the math as they go along.

Re:Interesting repercussions

[Ethanol-fueled]

Fail. Read my post any try again. I have already decided, based on my understanding(which includes having done my homework) of the two theories, that the big bounce makes much more sense to me than the big bang does. The reference to creationism was just an afterthought.

Re:Interesting repercussions

[Missing_dc]

So, instead of using rational thought and evidence to decide what theory is correct, you're going to use your "gut" feeling to make the determination? Sounds a little like what the relgionists, that you're so quick to deride, like to do.

The 100 trillion life forms that reside in my gut have faith in my ability to provide for them, why should I not listen to their prayers?

More than 500 different species of bacteria exist in our bodies, making up more than 100 trillion cells.
http://www.brainsturbator.com/articles/networks_bacteria_and_the_illusion_of_control

Re:Interesting repercussions

[Anonymous Coward]

And you are an idiot with a two digit number. Wow.

The big bang isn't a religious theory. It may be wrong and in fact, you have to accept that possibility in science.

Re:Interesting repercussions

[Mr. McGibby]

OK, read again. You still sound foolish.

Doesn't sound like an afterthought. Sounds like the whole point.

Re:Interesting repercussions

[interiot]

If something denser, like a star were to fall in, I doubt that the radiation pressure would push it away.

It's not just that it pushes gas away, it also gets to the point where it prevents star formation in its vicinity:

Furthermore, it appears that black holes can keep the gas too hot to settle in large quantities back to the galaxy's nucleus or to form stars through most of the galaxy's bulk. ... "So galaxies reach the point where you don't make stars."

But stars can still form elsewhere and be pulled in, yes. These black holes would be ~one tenth the mass of our galaxy, so they should be able to capture other galaxies that orbit it and eventually fall in.

Re:Interesting repercussions

[Visaris]

I came here to post almost the exact same thing. The story is about a limit to the size of black holes with respect to the ways the universe is expected to have developed. This is not a hard limit on the size but more of an equilibrium thing as the parent mentioned.

Think about this thought experiment:
One finds a black hole and shoots energy into it in the form of light in discrete sized packets or quanta. If the packets are put in faster than the natural blackbody radiation of the black whole releases energy through Hawking radiation, it will grow in size. Since the black body temperature of the hole decreases as it gets larger, it can grow in this way indefinitely. The larger it is, the softer it pushes outwards (w.r.t HR)...

The story is only really talking about matter/gas clouds, EM energy is an entirely different beast.

Re:Interesting repercussions

[cthulu_mt]

I have enough trouble with "dry counties"; the thought of a dry galaxy makes we want to weep.

Re:Interesting repercussions

[Anonymous Coward]

Lets see if we can clear some of this up for everyone...

When you have a black hole sucking in matter, that matter will start to get denser as it gets closer to the black hole. The larger the black hole the farther its gravitational influence and the more matter it can attract. As the matter falls in and gets denser its rotational momentum causes it to orbit. As this happens it starts to get quite close together and due to friction begins to heat up. Eventually it gets really really hot and expands as well as emitting high energy radiation. Once this reaches a critical point it overpowers the gravity of the black hole attracting said matter and starts blowing it back out.

Eventually this wind will be dissapated and will be inconsequencial on the scale of 100s of light years. Since galaxies are tens of thousands of LY across the intergalactic medium is not affected by this.

Again, this is not due to anything being emitted directly from the black hole, only the superheated matter falling into it.

Re:Interesting repercussions

[Anonymous Coward]

...some twat in the sky creating us..

All hail the Magic Celestial Vagina!

Re:Interesting repercussions

[Anonymous Coward]

And, by the way, there are branches of cosmology that contend that the universe, has, in fact, always been and will always be. It comes from the idea that as you measure time further and further backwards, you find yourself measuring time forwards again.

It's a really popular concept, but not with the people you'd expect:

http://en.wikipedia.org/wiki/Wheel_of_time

Re:Interesting repercussions

[mfh]

And you are an idiot with a two digit number. Wow.

The big bang isn't a religious theory. It may be wrong and in fact, you have to accept that possibility in science.

You misunderstood me. I was suggesting that this finding could result in the Big Bang theory being turned on its ear, which is an upset for science that the creationists would feed on, and we all know that it's a bad idea to feed creationists unless they are threatening to eat your young (and they do from time to time, just ask Sarah Palin).

I don't recall suggesting the big bang was a religious theory. But if you misread my comment, perhaps it was the terrible spelling in the grandparent that misdirected you? Oh wait... you are AKABatman!!! So you are calling me an idiot because I embarrassed you. Dude don't worry about it, I've forgotten to spell check before SUBMIT, too. It happens. Nietzsche was right! It's worse to publicly offend someone who has created an insignificant error than it is to condemn someone for acts they deserved. To hell! (that was a toast)

Re:Interesting repercussions

[Anonymous Coward]

Not quite right either. Nothing escapes a black hole except gravity. The radiation produced by a quasar comes from the super-heating of the gases as they are compressed rushing into the black hole.

What this article is saying is that the radiation (light/x-ray, etc.) pressure from this glowing super-heated gas is pushing away other incoming gases at a rate that "chokes off" the process.

Re:Interesting repercussions

[MikeDirnt69]

Until somebody asks where it all came from in the first place.

It came from the future!

Re:Interesting repercussions

[rrohbeck]

Those Hindus may not be far off:
http://www.sciam.com/article.cfm?id=big-bang-or-big-bounce

Re:Interesting repercussions

[AKAImBatman]

Um, dude. I'm right here. (*waves hand*) And I thought that post was rather unfair to your comment. My response would have been some sort of grumbling about the fact that Chrome didn't catch the spelling mistake when I copied and pasted it. (I did check! Worst. Spell. Checker. Ever.)

On his second point, I have no idea why anyone is trying to drag religion into this. As I recall, the original theory of the Big Bang was not acceptable to the Catholic church either. Funny thing, though. It wasn't acceptable to science, either. Until it was refined, many of the issues worked out, and the Pope stopped by to say "God created the Universe with a Big Bang". There. Settled on both sides.

Perhaps we'll prove tomorrow that both the scientists supporting the theory and the Pope were wrong. Maybe the next Pope will declare that God created the universe with a series of pops after science disproves the big ol' bang. Personally, I'm not really vested either way. :-)

As for the identity of the AC? Looks like Yet Another Slashdot Troll(TM).

Re:Interesting repercussions

[Tubal-Cain]

If something denser, like a star were to fall in, I doubt that the radiation pressure would push it away.

True, but that star falling in would increase the output of radiation (how permanent would that increase be?), and make a little bit harder for the next one to fall in. Eventually even the stars would be pushed away, and you'd have to step up to feeding it neutron stars (and eventually, other black holes). At least that's how I understand it.

Re:Interesting repercussions

[Windows_NT]

Im not a science guy, and my post might be too late to get an answer. What about how when you pull a plug in a drain, the water swirls and goes down, could this be the same, but the 'water' comes out somewhere else? like a different dimension? From what ive read about string theory and stuff in that math bracket, I would think the center of a black hole would have plenty of energy to rip a hole in a dimension and pour through. And i would think this would happen far before it could reach a saturation point, OR maybe that point is when the dimensions come apart.

Re:Interesting repercussions

[nschubach]

Aren't most hypothesis born from gut feelings? You are eventually educated to a point of understanding at which point things don't make sense. You get a "gut feeling" that it must be something else and you go about trying to prove it. (Or in this case reflect it off others to get feedback.) Then in trounces Mr. Wrong and steps all over your thoughts and tells you that you are wrong, without a doubt. "This is the way it is, and has been for years. So and so proved it and now you must comply." That to me sounds religious in nature. Because [I|God|We|They|Einstein] said so.

This frankly upsets me more than anything. The person so dead set in their ways that everything is black and white. There's no questioning allowed.

Re:Interesting repercussions

[Tubal-Cain]

And you are an idiot with a two digit number.

He paid for it
Apologies to mfh.

Re:Interesting repercussions

[nschubach]

What if the matter isn't entering the "event horizon" but is being shot out like a projectile from the other side and in doing so causes other object near it to follow? There are whole galaxies like this, but what if you looked at them from the "top"? Would they "look" like a black hole?

Re:Interesting repercussions

[ArsonSmith]

fast forward a few billion years when we have populated most of the galaxy. We start dumping our waist into black holes and the hippies come out of the woodwork, "What? We already messed up our dimension why are we ruining another dimension?"

Re:Interesting repercussions

[Ambitwistor]

Regarding your thought experiment: the cosmic microwave background radiation is a much larger influx than the Hawking radiation outflux of any stellar (or larger) black hole. So unless the black hole is isolated from the rest of the universe, it will always grow from cosmic radiation, even if no matter falls in. (Or at least until the universe expands enough that the background radiation becomes cooler than Hawking radiation; see here, in the second half.)

Re:Interesting repercussions

[Stripe7]

If I remember correctly from another forum, this article does not take black holes merging, into account. When two galaxies with central black holes around this limit collide, their cores will eventually merge into one above this limit. The maximum here is only for black holes pulling in normal matter not for interactions between black holes.

Re:Interesting repercussions

[steelfood]

Or perhaps nothingness is a state of equilibrium.

Re:Interesting repercussions

[blair1q]

"EM energy is an entirely different beast."

No it isn't.

The reason a black hole has an event horizon is that it has gravity. The reason it has gravity is that it has mass. If shooting energy into it can grow it, then shooting energy into it increases its mass.

But what if it doesn't? What if it just increases its temperature?

Then the black hole can increase its rate of radiating energy. Which will at some point repel particles and preven the accretion of further mass.

Increasing temperature can also increase the rate of "evaporation" of a black hole, which involves the creation of particle-antiparticle pairs through quantum uncertainty at the event horizon. A particle and antiparticle are created on opposite sides of the event horizon and follow different geodesics, with one falling in and the other pushed out. If the push is greater than the force due to gravity, the outer particle may never fall in.

One reason black holes are hard to see is sometimes they are very bright.

Re:Interesting repercussions

[bonch]

"It just is" sounds like a halt in the pursuit of answers.

Re:Interesting repercussions

[Anonymous Coward]

Until somebody asks where it all came from in the first place. Then you're back at square one, with the same problem that the Big Bang theory has.

Where it all came from in the first place? I think this is more kind of a last question ...

Re:Interesting repercussions

[exp(pi*sqrt(163))]

You made me all excited about astrophysics. I wish I had a telescope big enough to see M87's jet.

Re:Interesting repercussions

[HTH NE1]

Rather it's when the inflowing matter creates so much heat it clears out all the remaining matter in the area. Creates a "dry galaxy" (their term, not mine). So nothing left nearby for it to suck in and thereby grow.

Yeah, but it should still have an immense gravitational pull and drag matter into its area of influence again, flare up again, and self-extinguish again, effectively "sparking" repeatedly. It doesn't just become a source of anti-gravity, does it?

Re:Interesting repercussions

[E 99]

Side note: makes much more sense then the big bang theory, which reeks of creationism.

That was exactly the approach of the Scientific Religionists who denied the Big Bang for generations on that very basis. And then the cosmic background radiation was discovered, which put an end to the denial. Someone really needs to formulate a new Scientific Method, which doesn't make use of evidence. That way we can come up with scientific theories that smell just the way we like.

Re:Interesting repercussions

[qeveren]

The only way to increase the 'temperature' of a black hole is to reduce its mass, which increases the rate at which it produces Hawking radiation. Dumping EM radiation of any frequency into a black hole will only serve to -increase- its mass.

Stellar-mass and greater black holes are not bright; they're colder than the background radiation. The region surrounding them may be enormously bright, but the black hole is not.

Re:Interesting repercussions

[The Wooden Badger]

Great Scott!

Re:Interesting repercussions

[glitch23]

Unless you adopt the Hindu/Buddhist take on the cosmology... it wasn't created, it didn't magically poof into existence out of nothing: it just is. Always has been, always will be, and goes through periodic cycles of growth and destruction, without end.

Although that does conveniently ignore any hint of a Creation, it doesn't actually provide a useful answer which is what scientists are always searching for in order to be satisfied that the answer may be viable (along with whether the solution is "clean" or "beautiful"). It may be one reason why not many people have not liked that theory much (except Hoyle). There isn't any evidence that a constant expansion/contraction is occuring though which is probably the better reason why scientists don't go for the steady-state theory. It was possible when Hubble first discovered that the universe was expanding but when he discovered that the expansion is accelerating it makes it difficult for the contraction phase to ever get initiated.

Re:Interesting repercussions

[Anonymous Coward]

For a second I though you were talking about either the Force or going up against Xenu.

Re:Interesting repercussions

[arminw]

....but when he discovered that the expansion is accelerating ...

That was not a discovery, but an interpretation based on the assumption (belief) that the observed red-shift is due to the doppler effect. There is increasing evidence, that the red shift cannot be due to any large-scale motion or expansion of the universe.

Re:Interesting repercussions

[arminw]

....I'm not sure I buy that as setting an upper limit on the size of a black hole...

I am not sure that I buy existence of a black hole, since nobody has ever actually observed one. There are certain observations made which has been interpreted to be evidence of black holes. There are however other possible interpretations of that which is observed. Everything about black holes is based on mathematics which is in turn based on interpretations of certain observations.

Re:Interesting repercussions

[glitch23]

....but when he discovered that the expansion is accelerating ...

That was not a discovery, but an interpretation based on the assumption (belief) that the observed red-shift is due to the doppler effect. There is increasing evidence, that the red shift cannot be due to any large-scale motion or expansion of the universe.

What else creates red-shift? If there is increasing evidence ruling out large-scale motion (of what?) or expansion of the universe then what are they ruling in? All you said was accelerated expansion is wrong based on incorrect assumption of where the red-shift originated without saying what the proposed red-shift origination really is which can support the observed red-shift.

Re:Interesting repercussions

[arminw]

...Once this reaches a critical point it overpowers the gravity...

Any time a gas gets very very hot, it becomes a highly active plasma subject to electrical forces 36 orders of magnitude higher than gravity. Fast-moving charges, being accelerated by electrical fields of enormous intensity can produce incredible amounts of high-energy radiation. There is no known way to generate such radiation other than by accelerating charges. In addition to gravity, there must be considerable electrical activity in the neighborhood of any black hole if indeed there is even such a thing.

Re:Interesting repercussions

[Anonymous Coward]

That idea has its holes too. What can exist yesterday, today, and tomorrow? Once that is answered, then why concern yourself with anything else. Conversely, why concern yourself with it. For all intent and purpose, it has existed yesterday, today, and tomorrow. Focus on what matters, and that is being present. Which in itself is a singularity.

Re:Interesting repercussions

[fireboy1919]

Do they always assume that? I've always heard the phrase "heat death of the universe," which doesn't imply nothing...exactly, but it would be close.

Thanks to almighty laws of thermodynamics, we could theoretically reach a point where every bit of matter has been broken down into mere energy, and every quantum of energy is so far away from every other quantum of energy that no interaction ever happens again - everything stays in the lowest possible energy state, at the lowest level of organization.

If you could suddenly teleport to that time in the future, what you'd see for light years in every direction would be nothing at all. Sure, there'd be *something* since energy can't be destroyed.

It just wouldn't be doing much...probably not enough to detect.

Re:Interesting repercussions

[arminw]

...without saying what the proposed red-shift origination really is which can support the observed red-shift...

The red shift as measured, does not occur continuously, but in little jumps. That is, it is observed to be quantized. That observation tells us only one sure thing and that is the red shift cannot be due to doppler motion. It is inconceivable that stars and galaxies should move only in discrete velocities.

Since atomic phenomena are quantized, the observed quantization of the red shift must be in some way connected to atomic behavior. There is also evidence that certain constants, which govern atomic behavior, such as Planck's constant h and its inverse the speed of light c have not necessarily had the same value as we measure them today.

There is no law of physics that mandates that these "constants" should be invariant over overlarge spans of time. We also know from measurements, that the speed of light is greatly affected by the medium through which it travels. As the universe expanded from the beginning, possibly from what scientists have labeled a singularity, its density and therefore the properties of space itself has changed greatly. This would cause a continuous shift upward in Planck's constant h and a downward shift in c. Atomic orbits would not be able to shift continuously, but only in discrete quantized energy levels. This would affect mandate that the wavelengths of light radiated by stars and other celestial light sources also be quantized. This is what we indeed observe as we look back into the past of the universe.

If you are interested in researching this further, just google for "quantized red shift"/

Re:Interesting repercussions

[allgoodnamesaretaken]

* Full Disclosure: I did NOT include a referral code. This is a clean link

nothing wrong with referal links in my eyes if you are honestly recommending something. do people get flamed for it?

Re:Interesting repercussions

[Antique Geekmeister]

When does the light interact enough with that surrounding cloud of ruined matter and broadcasting energy to be caught there and blocked? Such a big black hole seems likely to have a fairly noticeable and thick shell. This is basically a shielding problem for the black hole, according to this paper. And that shell is likely to grow from whatever source created the black hole in the first place, such as a galaxy's mass, until it reaches some stable or semi-stable state.

You can't ignore the existence of that shell and say that EM will somehow magically pass through it untouched, anymore than you can say X-rays penetrate tissue without noticing the lead apron in front of it.

Re:Interesting repercussions

[VShael]

Don't feel bad, the physics is way beyond the string theorists, so they just make up the math as they go along.

Oh please. Physics and the so-called universe are just mere approximations of mathematical purity.

Re:Interesting repercussions

[Anonymous Coward]

There already is a children's book on relativity. A whole series actually, by Russell Stannard: http://www.amazon.com/exec/obidos/search-handle-url/ref=ntt_athr_dp_sr_1?_encoding=UTF8&search-type=ss&index=books&field-author=Russell%20Stannard
I loved them as a kid!

Re:Interesting repercussions

[Tenebrousedge]

And your alternate explanation is...?

Re:Interesting repercussions

[aproposofwhat]

Although that does conveniently ignore any hint of a Creation, it doesn't actually provide a useful answer...

It might point the way to an answer, though - just not one that fits neatly into our limited understanding of space, time and causality.

The elimination of the idea of a 'first cause' may actually reflect the way things are, rather than the way they appear to us through our limited view.

Anyway, it does away with all that God superstition, so it'll do for me :o)

Re:Interesting repercussions

[Ambitwistor]

See here for what the heat death of the universe would be like.

Re:Interesting repercussions

[Ambitwistor]

I don't waste my time arguing with creationist nutjobs like arminw, but just for the sake of scientific accuracy, you should know that cosmological redshift is NOT quantized into discrete redshifts. The people who claim so don't even understand what "quantization" means.

In the past there has been some weak evidence of a periodicity in redshifts in small samples of galaxies. "Periodicity in redshift" means that galaxies are more likely to be found at multiples of certain redshifts than others. It does not mean that the redshifts are quantized, meaning they only occur in discrete multiples. Even if you accept the claimed periodicity, there are most certainly plenty of galaxies (the vast majority, in fact) which occur at redshifts other than periodic multiples.

The studies which purported to find periodicities didn't all agree with each other as to which redshifts were the peaks. That's a hallmark of data-mining a spurious signal out of noise, a classic outcome of small-sample statistics. When you take into account any of the following factors (1) large sample sizes (we now observe far more galaxies than when those original claims were made), (2) the existence of large scale structure (you're going to see more galaxies at certain distances if that's where a supergalactic cluster is located), (3) sample selection bias, the "effect" goes away.

You should also note that periodicities in redshift do not contradict the evidence in favor of the expansion of the universe, either. Even if they existed, the most direct interpretation is that there is inhomogeneous large scale structure formation (which we already know there is, see point 2 above).

Re:Interesting repercussions

[Anonymous Coward]

The math far predates them [think Riemann], which is why we need NEW math to help our understanding now!

Re:Interesting repercussions

[xolo]

Taken well salted considering the source, but an interesting read nontheless: here. Summary is this: if the universe is not past-infinite, what are the philosophical and religious inferences we can make regarding the big bang.

Re:Interesting repercussions

[griffman99h]

All hail the Magic Celestial Vagina!

That's my wife you midget!

Re:Interesting repercussions

[sexconker]

XKCD is lame.

Re:Interesting repercussions

[arminw]

....And your alternate explanation is...?...

Most interpretation of cosmological observations, including black holes are based on the operation of the gravitational force alone. That is an interpretive assumption, not an observation. We know about other interactions besides the gravitational one, most notably the electrical force. Objects that have been interpreted to be black holes and other exotic constructs are observed to be giving off large amounts of highly energetic radiation. The only way known to science how to generate such radiation is by electrical means. It is also observed that there are large magnetic fields in space and on the Sun. Again, the only way we know of to generate a magnetic field is by the movement of electrical charges. In most currently accepted mainstream cosmological interpretations, the electrical force is largely ignored. For this reason it has become necessary to propose objects such as black holes with immense gravitational fields, to explain the energetic outbursts we observe in certain places of the universe.

Because the electrical force is 39 orders of magnitude greater than gravity, it would certainly dominate in any environment that is not largely electrically neutral, such as we have it here on earth. The most common form of matter in the universe is not gas, liquid or solid such as we are familiar with, but a highly charged, electrically active plasma, such as on the Sun, in the solar wind which envelops the earth and most of the solar system. Of the known fundamental forces of nature, gravity is actually the least understood, whereas we know and experience the electrical interaction every day. In the standard model of particle physics, gravity seems to stand out like a sore thumb that nobody really knows how to integrate with the other forces. It is hoped that experiments with the new LHC in Europe some observational light can be shed on this mystery.

In short, black holes, quasars and other "exotic" objects are mathematical fictions that are constructed to explain the observation of high energy phenomena by the action of gravity alone.

Re:Interesting repercussions

[paulgrant]

wuss :P thats just a bad a dodge as a bad explanation. There's nothing random about randomness, and just 'cause somethings here doesn't alway mean it was.

Re:Interesting repercussions

[Tenebrousedge]

IANAP

"The only way known to science how to generate such radiation is by electrical means."

False. In fact, the mechanism for doing so by gravitational means is what is described in this fine article.

"Again, the only way we know of to generate a magnetic field is by the movement of electrical charges."

Non sequitur. Are you suggesting that it is magnetism that keeps the planets in their orbits? They don't seem to be particularly perturbed by this insistence of yours that electricity be factored into this equation.

"In most currently accepted mainstream cosmological interpretations, the electrical force is largely ignored."

Only when it is not necessary. The principle of parsimony indicates that we should exclude other factors when they are not necessary or sufficient to explain observations.

Black holes were not actually proposed to explain observations. They were first theorized a century before Relativity, and should not be terribly difficult to understand. It is observed that light is affected by gravity--this is indisputable. It is not outrageous to consider that an object may be massive enough so that light cannot escape it. Relativity at this point is one of the most well-tested theories in the history of science; it does not completely describe black holes, but it is sufficient to show that if an object is massive enough, it will 'absorb' light.

Many people have attempted to disprove Relativity---if and when that happens, we may reconsider whether black holes exist. One would most likely have to assume that light is not affected by gravity in order to postulate the non-existence of black holes; I presume you have an alternate mechanism for gravitational lensing handy.

"The most common form of matter in the universe is not gas, liquid or solid such as we are familiar with, but a highly charged, electrically active plasma..."

You keep linking these factoids together as if they mean something. Perhaps you are just a great genius, to see these things where wise and learned men have not. Also, what you are describing aids rather than contradicts the idea that the large-scale universe is electrically neutral, the same way that plasma is. Additionally, the magnetic fields from this ubiquitous plasma are have been determined. In the case of the intergalactic medium, for example, this is about 10^-12 T. That's one hell of a substitute for Relativity there. I can see why you're excited.

"...gravity is actually the least understood, whereas we know and experience the electrical interaction every day."

I for one experience gravity on a daily basis...unless that's just magnetic forces in action? Right, because people in Faraday cages are weightless. Gotcha.

In short, non sequiturs won't cut it. Stop this handwaving and prove your statements. Start with disproving relativity, then explaining why the plasmas we measure are not of sufficient strength to explain any phenomenae explained by relativity (and do so without postulating exotic forms of matter). Hopefully this will also explain what we observe as gravitational lensing, which will dispel this idea that we can measure the masses of anything, which will discredit the observational evidence for black holes, and then you can work out the mechanism for particle acceleration (as observed). From then on, solving the mystery of dark matter and attaining the Lucasian Professorship should be a piece of cake.

Unless that damn global conspiracy of scientists gets in the way, I suppose. Parsimony and observations---they're a bitch, I tell you...

Re:Interesting repercussions

[arminw]

....In fact, the mechanism for doing so by gravitational means is what is described in this fine article...

No, it is an interpretation how such radiation MIGHT be produced by gravitational mens. However, here on earth, by actual EXPERIMENTS we do this daily using electricity. Nobody has EVER created even a single high energy photon by any means other than moving electrical charges. The same is true of magnetic fields.

(...Are you suggesting that it is magnetism that keeps the planets in their orbits?...)

No, of course not, but then planet are mostly electrically neutral. This is not true of the sun or stars. They are electrically active, as well as massive gravitationally. Gravity and electricity have to considered together.

(....when they are not necessary or sufficient to explain observations...)

That is the big problem, explaining the observations WITHOUT taking the electrical interaction into account as well, leads to some of the "exotic" constructs, such as black holes, quasars, dark matter and dark energy. If electricity and its accompanying magnetic fields are ALSO considered, the need for such exotica disappears and the universe, even very far away becomes just as ordinary as it is here around earth and our solar system.

(..It is not outrageous to consider that an object may be massive enough so that light cannot escape it...)

Just because it is mathematically possible to conceive of and calculate the possible properties of such an object, doesn't mean automatically that such a thing must actually exist in reality. The same can be said for the other exotica cosmologists mathematically theorize. Mathematics and science are NOT one and the same.

(..Relativity at this point is one of the most well-tested theories in the history of science...)

True, as I experienced first hand when we first switched on the Stanford Linear Accelerator back in 1967. IF, and that is an unproven IF, black holes, if they existed not only in mathematical interpretations of observations, but could be directly observed, should be subject to relativity. Indeed, IF an object really existed that were as massive as black holes are theorized to be, it should "absorb" light. My point is, that well known and tested electrical laws can equally well, in a much simpler fashion explain the observations we actually make.

(...You keep linking these factoids together as if they mean something...)

Are you disputing that plasma is NOT the form in which most matter in the universe occurs? The cosmic background radiation is an ELECTRICAL fact we actually measure. The whole Universe is pervaded by electrical activity. Plasma is definitely NOT electrically neutral neither here on earth in real experiments, nor in the reaches of distant galaxies.

(...I for one experience gravity on a daily basis..)

So does everybody else. We also experience time and yet there also, nobody really knows what and why there is this thing we call time and why it seems to only go in one direction. Just because something can be measured and experienced, doesn't tell us its intrinsic nature.

(...Start with disproving relativity...)

Why? If the conjectured, exotic entities in space were real, they definitely would be affected by relativity. The existence of relativity doesn't affect whether these things exist in reality, rather than only in mathematical theories.

(...Hopefully this will also explain what we observe as gravitational lensing...)

What we actually observe is the fact that star light passing near an object, such as a our sun is slightly displaced or bent. This has been INTERPRETED to be due to the gravity of the sun. Since light is an electrical activity, it will respond to any electric fields in the neighborhood of the sun 36 orders of magnitude more readily than gravity. So what has been attributed to gravity can also be caused by an electric or magnetic field, including the high radiation from the sun and the solar wind.

I cannot understand WHY the present cosmo

Re:Interesting repercussions

[Anonymous Coward]

Given that the universe appears to be expanding at an increasing rate it means the universe is unlikely to contract again, why do you think the big bounce theory makes more sense?

Tens of billion?

[courteaudotbiz]

few tens of billion of solar masses

Since when "tens of billion" is "few"?

Re:Tens of billion?

[OglinTatas]

When your national debt is in the tens of trillions

Re:Tens of billion?

[Hatta]

So the phrase "astronomical numbers" is now superseded by "economical numbers".

Re:Tens of billion?

[eldavojohn]

When your national debt is in the tens of trillions

Stop spreading FUD, it's only a single ten of trillion.

Re:Tens of billion?

[megamerican]

Stop spreading FUD, it's only a single ten of trillion.

You are forgetting the unfunded liabilities the American taxpayer is on the hook for which is $60+ trillion.

Re:Tens of billion?

[dreamchaser]

It just means more than 1x10 billion but not many multiples thereof. Yes, it's a fuzzy definition.

Re:Tens of billion?

[PyroFred]

I would think the that "tens of billion" is realativly "few" when regarding thing on such a grand scale. It would be the same scale if it was say, cells in a human body. The number is large, but realativly it is only a few.

Re:Tens of billion?

[SpeedyDX]

Or "economic numbers".

Trying not to be a grammar nazi (and obv failing), but the generally accepted definition of "economical" is to the effect of "thrifty" or "prudent", ant., "wasteful". "Economic", on the other hand, refers to that which pertains to the economy, or science of economics, etc.

Re:Tens of billion?

[Anonymous Coward]

I don't know, 20 billion solar masses of gold would cost $1.029 times 10 to the 45 dollars, and 20 billion solar masses of light sweet crude would be 284.131 times 10 to the 36 barrels and would cost about $17.937 times 10 to the 39 dollars. At today's prices. So the national debt is really nothing against that.

At least if my calculations are correct.

Re:Tens of billion?

[courteaudotbiz]

if my calculations are correct

Thanks, Doc Brown!

Re:Tens of billion?

[Anonymous Coward]

... Or when you throw around $810 billion around at the strippers

Re:Tens of billion?

[gv250]

There are 10^11 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.
Richard Feynman, US educator & physicist (1918 - 1988)
http://www.quotationspage.com/quote/26930.html

Re:Tens of billion?

[bugi]

But those are pretend dollars, so they don't count.

Re:Tens of billion?

[nedlohs]

That is part of Feynman's joke.

Re:Tens of billion?

[sexconker]

If we had that much gold, it would cease to be valuable.

Re:Tens of billion?

[shawb]

I think that phrase was slightly mistyped. I parsed it as a few (tens of billions.) I assume they are using English units, in which a few is about a half a handful, which is somewhere around 10-12. So they are saying about 50-60 billion solar masses.

Re:Tens of billion?

[megamerican]

But those are pretend dollars, so they don't count.

Shhh... People aren't supposed to know that!

Re:Tens of billion?

[ari wins]

Love that quote, used it as a sig on a few forums for a while!

Re:Tens of billion?

[Firehed]

Aside from the complete failure of scientific notation, you need to take into account that if we suddenly came across a black hole made of pure accessible gold or oil, the prices on said commodity would drop to below nothing.

Re:Tens of billion?

[jcnnghm]

Given that Medicare is already the single largest unfunded liability (at $255,280 per household), is it really prudent to socialize healthcare at this time, creating an even larger liability?

Re:Tens of billion?

[DamnStupidElf]

Aside from the complete failure of scientific notation, you need to take into account that if we suddenly came across a black hole made of pure accessible gold or oil, the prices on said commodity would drop to below nothing.

Leave it to the Republicans to try mining a black hole for resources ;)

Re:Tens of billion?

[budgenator]

in breaking news, the Bush administration ordered all NASA websites to report astronomical distances in the more appropriate metric unit of measure the meter.

Phew...

[Richard_at_work]

Thats nice to know, another less thing I have to worry about!

Agreed, Very Interesting repercussions

[eldavojohn]

It is thought that black holes of such size heat the surrounding gas to a temperature where the radiation pressure begins blowing outer layers into space.

Well, I'll admit this sounds intuitive with the Penrose-Hawking singularity theorems applied to the Big Bang. Now, I'm not a physicist either but I have read a lot that speculates the Big Bang was a singularity that created a hot unstable mess. All the mass of the universe in a singularity suddenly starts blowing out and producing massive heat. Although what was around this singularity is nothing--not even space.

As always, it brings up interesting questions about what was before that epoch since it is kind of clear that such a singularity could not be possibly be stable for any amount of time (as this research indicates).

** Someone should really make a joke out of LHC doomsday and how we're all saved. I couldn't come up with anything funny.

I was trying to relay what I had read about the micro black holes the LHC is trying to create to a female coworker. I failed. She told me someone in India committed suicide facing the LHC being turned on. All I could think of was that I really wish they called micro black holes that exist for minute fractions of a second something other than "black holes." It scares people unnaturally.

Re:Agreed, Very Interesting repercussions

[Clandestine_Blaze]

All I could think of was that I really wish they called micro black holes that exist for minute fractions of a second something other than "black holes." It scares people unnaturally

What scares me unnaturally is the uncanny resemblance. We're doomed!

Re:Agreed, Very Interesting repercussions

[Anonymous Coward]

I was trying to relay what I had read about the micro black holes the LHC is trying to create to a female coworker.

For some reason I read this as "LHC is trying to create a female coworker", and I thought that was a pretty funny joke, until I realized that wasn't what you meant to say at all.

Re:Agreed, Very Interesting repercussions

[sexconker]

Seems to me that that Large Hardon Collider would be seeking to create male coworkers.

Re:Agreed, Very Interesting repercussions

[psychicninja]

As always, it brings up interesting questions about what was before that epoch...

The Sixties?

Re:Agreed, Very Interesting repercussions

[mcgrew]

All I could think of was that I really wish they called micro black holes that exist for minute fractions of a second something other than "black holes."

Microscopic singularities. Of course, the press wouldn't eat that up; newspapers don't exist to educate the public, they exist to generate revenue.

Re:Agreed, Very Interesting repercussions

[Anonymous Coward]

such a singularity could not be possibly be stable for any amount of time/quote>

That's fine, since "before" the Big Bang, there not only was no space, there was no time, either.

Not that I'm saying the question what came before the Big Bang isn't an interesting one, but I don't think one can just say "the singularity can't have been stable, therefore, there must've been something before it". It may well be that there simply wasn't a before.

Re:Agreed, Very Interesting repercussions

[Nimey]

If fools kill themselves over stupid shit like that, the gene pool's better off without them.

Re:Agreed, Very Interesting repercussions

[HTH NE1]

All I could think of was that I really wish they called micro black holes that exist for minute fractions of a second something other than "black holes."

Bugophants?

Actually, in that book they don't evaporate and never stop eating, but they do send information back in time commensurate with their size.

Re:Agreed, Very Interesting repercussions

[Anonymous Coward]

No kidding. Besides, if the world were to be destroyed by a black hole, wouldn't you want to stick around to at least see what it was like?

Not to mention the huge party and the ability to use lines like "Hey, we're all going to be dead tomorrow, why not?"

Re:Agreed, Very Interesting repercussions

[Ambitwistor]

Well, I'll admit this sounds intuitive with the Penrose-Hawking singularity theorems applied to the Big Bang.

No, it has nothing to do with singularities (or the Big Bang). It has more to do with matter which orbits black holes.

Now, I'm not a physicist either but I have read a lot that speculates the Big Bang was a singularity that created a hot unstable mess. All the mass of the universe in a singularity suddenly starts blowing out and producing massive heat. Although what was around this singularity is nothing--not even space.

Don't think of the singularity as a point that blew matter in all directions. As you correctly note, there is nothing "around" a singularity. For now limit consideration to an infinite universe, which is preferred by standard inflation scnearios. Then a singularity isn't even really a single point. The universe is still infinite in extent, it's just that the matter/energy in it is of infinite density. (See here.) Think of the Big Bang as where space expands making the matter less dense, rather than some single location that spews matter away from itself.

As always, it brings up interesting questions about what was before that epoch since it is kind of clear that such a singularity could not be possibly be stable for any amount of time (as this research indicates).

To reiterate, this research has nothing to do with the singularity inside of black holes. It has to do with matter which is outside black holes not being able to make its way in, due to the pressure created by other infalling matter. The black hole itself does not emit any appreciable matter/radiation (other than a very tiny amount of Hawking radiation).

All I could think of was that I really wish they called micro black holes that exist for minute fractions of a second something other than "black holes." It scares people unnaturally.

I agree. "Micro black hole" is a terrible name. I prefer "Death, Tiny Destroyer of Worlds".

Re:Agreed, Very Interesting repercussions

[doublebackslash]

XD Wish I had mod points

Re:Agreed, Very Interesting repercussions

[Fourier404]

It is questionable if it is acceptable to do so if they are end-term on a horrific disease, due to the chance of recovery.

The girl in India thought that she was at the end-term of humanity with zero chance of recovery. According to what she knew, even your definition makes her suicide acceptable.

Re:Agreed, Very Interesting repercussions

[Hordeking]

Nope. They have to create both, due to Pro-IP, DMCA, Affirmative Action(tm), and the civil Rights Act of 1964.

The real problem is when the time comes to find out which one you got, due to quantum entanglement, Heisenburg's uncertainty principle, and of course, wave functions. It turns out that observing it will cause it to collapse into a male coworker, a female coworker, or a persnickety cat, with no way to pick one over the others.

Re:Agreed, Very Interesting repercussions

[davolfman]

Hawking explosion?

Re:Agreed, Very Interesting repercussions

[aproposofwhat]

"if you can remember them, you probably weren't there"

Though after the shock news of myelin erosion increasing after the age of 39, most of us who were there are now struggling to remember...

Oh, and get off my lawn :P

Re:Agreed, Very Interesting repercussions

[aproposofwhat]

"Death, Tiny Destroyer of Worlds"

So that's a microVishnu, then?

Re:Agreed, Very Interesting repercussions

[OldManAndTheC]

microShiva to be accurate. Shiva is the destroyer, Brahma the creator, Vishnu the preserver.

Or to put it in Slashdot-friendly terms:

Brahma writes the code
Vishnu maintains the code
Shiva accidently overwrites the project folder with pr0n

Re:Agreed, Very Interesting repercussions

[aproposofwhat]

As far as I was aware (bearing in mind that the last time I read the Bhagavad Gita was at school 30 years ago), all are aspects of Vishnu.

You're right, though - microShiva is more precise.

What if our universe were one big black hole?

[PrescriptionWarning]

I either just blew your mind, or sucked it.

Re:What if our universe were one big black hole?

[Rayeth]

science never sucks, it can only blow.

Re:What if our universe were one big black hole?

[elFarto the 2nd]

I saw an interesting interview with Michio Kaku here, and he talks about just this.

Re:What if our universe were one big black hole?

[sexconker]

That, sir, depends on your frame of reference.

Re:What if our universe were one big black hole?

[hierophanta]

science never sucks, it can only blow.

unless you work for Dyson - in which case science never loses its sucking power

Re:What if our universe were one big black hole?

[Anonymous Coward]

see a Spaceballs quote coming...

"Oh, my God. It's Mega Maid. She's gone from suck to blow. "

Consistent with interracial porno.

[bloodninja]

While I've noticed that white chicks' holes grow in a linear fashion to their, um, workload, the black chicks' holes grow in a logarithmic fashion. So at first they grow fast, but then they tapper off and after some time there is barely any noticable growth.

Thai chicks, on the other hand, seems to vary by a sine wave. God, I've got to get to Thailand.

Re:Consistent with interracial porno.

[mfh]

Thai chicks, on the other hand, seems to vary by a sine wave. God, I've got to get to Thailand.

First, get out of your parents basement, then explore THE WORLD. Go, outside!

Re:Consistent with interracial porno.

[sanosuke001]

So, white chicks progressively get sluttier as tehy get older, black chicks start out slutty and can't really get sluttier from there, and thai chicks have cycles?

Re:Consistent with interracial porno.

[bloodninja]

So, white chicks progressively get sluttier as tehy get older, black chicks start out slutty and can't really get sluttier from there, and thai chicks have cycles?

That's what us basement dwellers have been led to believe.

Re:Consistent with interracial porno.

[mcgrew]

OT but I have been to Thailand. Considering your comment, I think you might be interested in this ole K5 diary.

I've heard that "once you do black you never go back" but that's not been my experience.

Watch out for that Event Horizon Tsunami!

[PolygamousRanchKid]

When your national debt is in the tens of trillions

Stop spreading FUD, it's only a single ten of trillion.

That was true when you posted, but in the meantime ... that national debt grows like crazy ... he must be eating his "Wheaties" ...

Re:Watch out for that Event Horizon Tsunami!

[genner]

That was true when you posted, but in the meantime ... that national debt grows like crazy ... he must be eating his "Wheaties" ...

We should stop making pennies then......*rim-shot*.....*crickets*.......so ashamed.

Limits on balck holes?

[oodaloop]

Clearly they've never been to goatse.

Re:Limits on balck holes?

[Tatisimo]

Goatse is more like a virus than anything else. Once you are goatsed, you must goatse others. Goatse shold be studied by biologists, not cosmologists.

Colliding black holes

[CubicleView]

I'm sure I'm basing this on some bad sci fi movie or other, but can't two of these maxed out black holes merge together (in theory at least) to form a larger one?

Re:Colliding black holes

[corsec67]

Or would the black holes repel each other, possibly leading to clusters of black holes like The Maw?

Re:Colliding black holes

[AstroWeenie]

I'm sure I'm basing this on some bad sci fi movie or other, but can't two of these maxed out black holes merge together (in theory at least) to form a larger one?

Actually this is a very good question and was the first thought I had too. (And I am an astrophysicist.)

It looks like the answer that the paper offers is that to have two extremely massive black holes in the same galaxy would require that galaxy to be more massive than any we have found. There's a close correlation between the mass of the central black hole and the mass of the galaxy.

I consider this a slightly weaker explanation though, compared with the argument that the black hole can't continue to grow because gas can't accrete to it.

Re:Colliding black holes

[Urkki]

This "limit" is just a practical limit. If this is correct, then it's just very hard to feed a lot of mass to thig big a black hole, because if you try to feed it too much, it'll blow away most of the mass you were trying to get in. So considering the age of the universe, and the mechanisms by which they accrete matter, you get a max size for the biggest black hole possible.

But if you merged two such black holes, you'd probably get a much bigger black hole, and there would be no limit. Or if there was a limit, it would be due to entirely different effects. Our current theories like General Relativity might not even hold in a situation where two really really big black holes collide, so what would happen is anybodys guess.

Re:Colliding black holes

[Veinor]

Yeah they can. But that's a pretty anomalous event, and I think the article is talking about the standard methods of black hole formation.

Re:Colliding black holes

[budgenator]

of course the chances of two blackholes colliding head on are quite small, but two going into a binary death-spiral would produce effect that would be mind-boggling. The tidal forces could easily rip holes in the event horizons allowing mater to spill out into the central regon

This was in my kids book

[Anonymous Coward]

This was in my kids book. I just read it to him last night.

LHC doomsday

[Anonymous Coward]

As an optimistic observer-moment, I'm sure it won't occur. Every universe in which the LHC fired up successfully has been destroyed already.

We'll see a few more spectacularly random failures before our scientists realize that the safe bet is to permanently deactivate the thing.

Just Like MRIs

[Anonymous Coward]

What we today call MRI (Magnetic Resonance Imaging) used to be called NMRI (Nuclear Magnetic Resonance Imaging). As with "Black Holes", people were afraid of anything "nuclear"; hence the name change.

Re:Just Like MRIs

[Taint Bearer]

Same reason why ITER isn't an acronym anymore. It was previously known as the International Thermonuclear Experimental Reactor (ITER), and is know known only as Iter, which means 'journey' in Latin (even though it's in France). Seems that some people aren't to crash hot about something with experimental and nuclear in the same sentence.

Re:Just Like MRIs

[ppanon]

Heh. I remember when my high school senior physics class took a tour of TRIUMF. TRIUMF is synchrotron - a type of particle accelerator. This was a few years after the release of "The China Syndrome" but before "Silkwood". Because we all had to wear visitor badges to measure radiation exposure, one of the people in the group asked (and had to be reassured twice) whether there was any possibility of a meltdown-type nuclear accident.

Joe SixPack and Joe the plumber probably never took any physics in high school beyond lower-level mandatory science classes, so it's no wonder that most Americans completely misunderstand the risks and are so easily manipulated on the subject.

That said, I wouldn't want anywhere close to my home a nuke plant that was run by a for-profit company with incentive to cut inspections and maintenance levels so low that accidents would happen. I don't care that a whole regulatory apparatus might be in place now to monitor and control maintenance levels when they can buy politicians over a 10-20 year time-frame to gut the regulatory apparatus.

I think nuclear power can be safe and needs to be an option in the power generation game, but it needs to be run by highly regulated non-profit corps to limit the biggest risks, which stem from greed and corruption.

Re:Just Like MRIs

[Hordeking]

Non-profits aren't immune to corner-cutting and greed, either.

Re:Just Like MRIs

[profplump]

Ignoring the fact that non-profit groups might have the same reasons for cutting corners -- couldn't you use economic incentive to make corner-cutting unattractive?

For example, we could create a $500,000 tax credit for any inspection company that finds a significant violation not found by any previous inspection company (and fund it by fining the plant and/or the first inspection company). Then all you have to do is require inspection by at least 2 outside companies. It's possible to bribe them, but if you make the reward for finding faults high enough it quickly becomes cheaper to just avoid violations in the first place.

Re:Just Like MRIs

[profplump]

Would you rather have a cost-cutting plant with hundreds of tons of high volatile fuel full of poisonous (and radioactive) chemicals and no containment dome near your home?

Or live next to train tracks where easily-gasified, extremely poisonously chemicals are shipped at high speed in relatively thin metal containers that are *not* designed to withstand crashes?

Sure, nuclear contamination (sometimes) has a longer threat timeline, but that's not really important if you're living there when it happens. And with the safety features that are standard in all plants even considerable negligence in a nuclear plant less dangerous than many other threats you don't bother to consider.

Re:Just Like MRIs

[ppanon]

I said highly regulated. I didn't say how. Your approach is intriguing. However I think that it has its flaws as well. While trying to get a bounty might work as motivation, in an environment where nuclear operators are afraid of giving up a bounty, you could also get an inspecting organization that hires cheap inexperienced inspectors because they can pay them less and have greater profit margin on the inspections. They would have a competitive advantage so that other private auditors would be forced to adopt similar approaches to avoid being underbid, until the point where all the auditing companies are barely competent and your power producers figure out they can skimp on maintenance without anybody catching on.

Perhaps have one inspection done by the public sector (DoE or equivalent) and one by the private sector? The competition for prestige might help both keep a higher quality of inspection, because you can compare the results and see which one missed more. That can help with promotion/bonus decisions in the public sector and contracting decisions on the private side and reduces the chance of collusion that might exist if there were only private sector companies.

Re:Just Like MRIs

[ppanon]

Ignoring the fact that non-profit groups might have the same reasons for cutting corners

It's less of an issue. For-profit corporations in the US are required by law to maximize profit for shareholders. Non-profits usually have different priorities. Sure there's still a lot of potential for individual greed gumming up the works, but non-profit organization eliminates a whole class of failure modes. For some types of enterprises, society is willing to accept the risk of those failure modes in exchange for the increased efficiency that they can provide in delivering a desired product. However a very strong argument can be made that the production of energy through nuclear fission has sufficiently bad potential consequences (thousands or millions dying and trillions' worth of land and resources unavailable for decades vs. a few thousand people out of work) that the greater efficiencies sometimes available through for-profit organizations are not worth the risk.

Re:Just Like MRIs

[Anonymous Coward]

Given the hysteria of some portions of the population to anything nuclear and general wariness of it by most other people, surely it would be political suicide for any politician to do anything to make nuclear power less safe, so it's unlikely any politicians would consider doing it even if they were offered personal incentives to do so.

Re:Just Like MRIs

[Anonymous Coward]

Boy, you don't even know your own legislative system do you?

The way this is easily gotten around is that you bury it on page 451 of a bill that funds veteran's benefits, extra personal body armor for the armed forces, special funding for counter-terrorism, moms, and apple pies in the 24 hours before the last reading. Then if anybody shows any sign of voting against it, you hammer them in the media with "They're voting for terrorism and against veterans, moms, and apple pie!!". Done deal.

Stable Structure?

[corsec67]

What if there was a black hole, at this size limit, inside of a very dense cloud of gas?

Would it look like an enormous gas planet to an outside observer?
If the gas cloud was dense enough, could fusion start, creating a star with a hollow region between the "star" part and the black hole, held in place by this "radiation pressure"?

Hmm, what if the external part started becoming solid? Would it be like a planet, but inside out with "gravity" provided by the pressure from the black hole? Of course the radiation on the inside would be huge. Would the outside have tolerable gravity levels, due to the empty space inside?

Heh, I think I have one sentence there that isn't a question.

Re:Stable Structure?

[ceoyoyo]

It would look like a very dense cloud of gas first being turned into a rapidly rotating disc, heating up enormously, then being shot out in jets, from the poles.

Re:Stable Structure?

[freeasinrealale]

Yes this in fact a plausible structure. My mother in law served one up for dinner last Xmas.

Big Crunch?

[Culture20]

Does something like this throw the Big Crunch (and cyclical universe by extension) out the window?

Re:Big Crunch?

[Ambitwistor]

No. No amount of pressure can prevent a collapsing universe from collapsing; that's the content of various cosmological singularity theorems. This doesn't even prevent simple things like galaxies colliding. It really only works because a black hole event horizon is relatively small, and it's hard for a lot of matter to all cram in. But in a collapsing universe, once you get to the point that things are starting to collide, the collapse has already built up enough that it's unstoppable. Past a certain point, pressure itself gravitates more than it repels. That's why black hole collapse is inevitable beyond a certain critical mass.

Re:Big Crunch?

[dwye]

> Does something like this throw the Big Crunch (and cyclical universe by extension) out the window?

The Big Crunch has been "out the window" for some time, now. The current expectation is of a Big Rip, when the expansion of the Universe, which is apparently proceeding faster as time goes on, becomes so great that, first, all the galaxies outside of the local group will be receding too fast to be seen. Some months later, the Local Group will rip apart from the expansion, leaving just the Milky Way and its gravitationally bound galaxies. Shortly after, the galaxy will be receding and rip apart, leaving just the Solar System with a coal-black sky. But don't feel bad about that, because a few days later, the Solar System will be ripped apart by the expansion, and so on, at faster rates, until even composite elementary particles like hadrons will rip into a quark or gluon per whatever, effectively per Universe.

Well, doesn't THAT brighten up your day?

Re:Big Crunch?

[Ambitwistor]

No, a Big Rip isn't the currently preferred scenario. An accelerating expansion due dark energy, yes. But one that accelerates so fast as to ultimately rip apart matter requires an extreme form of "phantom dark energy", which is not observationally favored.

Wait a second

[Anonymous Coward]

only few tens of billion of solar masses?

He's quoting Feynman-

[Petskull]

He's quoting Feynman:

"There are 10^11 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers." -- Richard Feynman

Also: Economical Number
A number n is called an economical number if the number of digits in the prime factorization of n (including powers) uses fewer digits than the number of digits in n. The first few economical numbers are 125, 128, 243, 256, 343, 512, 625, 729, ... (Sloane's A046759). Pinch shows that, under a plausible hypothesis related to the twin prime conjecture, there are arbitrarily long sequences of consecutive economical numbers, and exhibits such a sequence of length nine starting at 1034429177995381247.
http://mathworld.wolfram.com/EconomicalNumber.html

not so fast!

[Lord Ender]

You can test these theories like you test software. Consider an edge case.

Suppose there exist two of these "maximum" density black holes on a collision course. Sure, the "radiation pressure" may exceed gravity at some point for low-momentum gas particles, but that doesn't mean the pressure would be so much greater than gravity that it would halt an oncoming super black hole (with corresponding super momentum!).

It seems in such a scenario it would be possible to form a black hole with double the "maximum" mass.

Re:not so fast!

[kungfugleek]

It seems in such a scenario it would be possible to form a black hole with double the "maximum" mass.

I call it a "Hawking Hole".

Re:not so fast!

[ceoyoyo]

The paper (not the summary) doesn't suggest that you can't have bigger black holes, just that you generally won't because the normal way black holes grow has limits.

Note that anything that's not actually another black hole will get torn apart by tidal effects, and two 30 billion sun mass black holes colliding is likely to be a fairly uncommon event.

Re:not so fast!

[budgenator]

I'm not so sure about that, not being a math whiz I can't prove it, but it seems that a 30G solar mass black hole would have a very very large event horizon which would greatly reduce the tidal forces. The lunar tide has little effects on my body, a 30G SM blackhole may not have much effect on a star the deltaG would likely be too little. All we know about blackholes is mass, charge and angular momentum everything else is lost crossing the event horizon; in fact if the horizon is big enough one might even cross it unnoticed, this is called weak spaghettification.

Re:not so fast!

[ceoyoyo]

Interesting. Let's see:

Classically, Fg = GMm/r^2

For a sphere, r = R +- deltaR, where deltaR is the radius of the sphere. That gives us

Fg = GMm/(R+-deltaR)^2.

The event horizon of a non-rotating black hole is located at the Schwarzschild radius, which is given by:

rs = 2GM/c^2.

For our 30 billion solar mass black hole, that works out to about 88.5 billion km (8.85 * 10^13 m).

Back to our force equation, R = rs, M is 30 billion solar masses, m is one solar mass and deltaR is one solar radius (let's throw the sun into the black hole).

Working it out, Fg- = 1.011484 * 10^33 N, Fg+ = 1.011452 * 10^33 N.

Subtracting the two, there's a force differential of 3.18 * 10^28 N across the sun.

Okay, that's interesting, but it doesn't tell us whether the sun gets ripped apart.

Calculating the Roche limit for something non-rigid like the sun is tricky, but Roche gave an approximation:

d = 2.44*R*(pM/pm)^1/3 where pM and pm are the density of the black hole and the sun, respectively. The density of a black hole is a bit tricky, but if you look at the derivation of that formula, the density they're using is just the mass over the volume, so pM/pm becomes:

(M*deltaR^3) / (m*R**3), which makes a lot more sense (the constants in the volume equation cancel out). Working everything out gives a Roche limit of d=5.3 * 10^12 m. That IS less than the radius of the black hole.

That's all a classical treatment, which probably isn't going to work very well when you're close to an event horizon. Some other effects that might get involved are heating and compression. The black hole doesn't just pull things apart, it also squishes them. When you squish a star they tend to blow up. Heating them up and irradiating them with x-rays probably has similar effects.

So... I'm going to say inconclusive. If you chucked a star straight into the black hole it would probably make it. If you put your star in orbit around the hole (a more realistic situation) I suspect it probably wouldn't. At the least the radiation pressure would presumably maintain it's orbit just as well as it would for free gas. I wonder if the sun would sweep up enough material in the accretion disk to do whatever stars do when they get too big?

Re:not so fast!

[Ambitwistor]

The tidal force isn't too much different, relativistically. Dimensionally the tidal force still has to look something like GMm/R^3 deltaR. I looked up the relativistic calculation in Misner, Thorne, and Wheeler (in Section 32.6, with the charming running title "Gore at the singularity). There should be a 1/4 in front of that expression. The horizontal compression in any direction is half that of the vertical tension. I am no expert on what that would do to a star.

No matter ejected from inside the hole

[iamlucky13]

They're not saying that matter is ejected from inside the hole, so no, stars wouldn't be recycled. Also, they are not saying black holes at galactic cores are at this limit. Sagittarius A*, for example, which lies at the center of the Milky Way, is estimated to be only 3.7 million solar masses...orders of magnitude below this theoretical maximum. Also, such a wind as you suggest should be observable as it interacts with free gas and dust in the Milky Way. This may sound hard to believe, but it is in fact regularly observed in supernova remnants and massive stars like in the Crescent Nebula.

So what they're actually decribing is gas, dust, etc in the accretion disc orbiting near but not yet swallowed by the black hole. As stated, this gas becomes superheated and expands as it swirls ever closer to the hole. They claim that at some point the heat grows so intense that like a Wolf-Rayet star at the Eddington limit, it just blows all of the remaining gas away from itself to form a big bubble of relative emptiness. The article fairly descriptively labels this as a "dry" black hole. Actually, going back to the star recycling concept, this effect may be so dramatic as to actually prevent star formation in the host galaxy for the predictable future.

At this point I think the description is a little sloppy, since the black hole would then be devoid of material to compress and heat, and therefore the "black hole wind" (AC's insert crude fart joke here) effect is now gone. Theoretically then, feeding is able to occur at slow rates, and reading between the lines of the article, it sounds like the researchers agree about that. However, it would not allow the super-fast feeding behavior that results in the distant strobes known as quasars, which are believed to be such super-massive black holes below this limit.

Ultimately what they're suggesting is that quasars can't last forever because eventually their growth slows down to practically nothing, and then you have a relatively quiet, but huge black hole. Please keep in mind, however, that the end of the article disclaims this as being speculative physics. It makes sense, and it seems to fit the data, but it hasn't been thoroughly validated yet.

Re:No matter ejected from inside the hole

[Anonymous Coward]

You asked, so I must deliver:

At this point I think the description is a little sloppy, since the black hole would then be devoid of material to compress and heat, and therefore the "black hole wind" (wouldn't this be more of a brown hole wind?) effect is now gone.

I feel cheap for doing that, hence the AC post.

Perhaps good enough..

[elloGov]

...to suck up all the a**holes who seem to have no growth limit.

slashdot editor fail...

[g0dsp33d]

the maximum size a black hole may reach is only few tens of billion of solar masses

Physics understanding fail! Volume != Mass

Re:slashdot editor fail...

[kosack]

It's not totally crazy - when talking about black holes, the "size" of the black hole refers to it's Schwarzschild radius, which is directly proportional to its mass. Though you're probably right that in this case it's just a mistake!

Re:slashdot editor fail...

[ceoyoyo]

For black holes "volume" (as far as that term applies) is strictly related to mass. Note also that "size" does not necessarily imply "volume," particularly for objects like black holes.

Comment removed

[account_deleted]

Comment removed based on user account deletion

Where does the energy come from? Hmmm?

[argent]

The energy to blow away the dust and gas from the black hole comes from infalling dust and gas. In the absence of infalling dust and gas the black hole doesn't emit any energy at all. So once it reaches this limit, and clears out the nearby vicinity of the hole, what keeps its neighborhood clear? It's no longer taking in matter, the radiation pressure drops, and the expelled matter eventually returns to start te growth again, no?

This all sounds like the T-Tauri stage in stellar evolution... except that the star continues to radiate, and the black hole doesn't.

Re:Where does the energy come from? Hmmm?

[Dan Ost]

Black holes do radiate particles (search for "hawking radiation" on Wikipedia), but that's not what they're talking about here. As matter falls into the black hole, it gets superheated and radiates lots of EM. Thus, it isn't radiation from the black hole that clears out the surrounding space, but radiation from the matter falling into the black hole.

Re:Where does the energy come from? Hmmm?

[argent]

Black holes do radiate particles (search for "hawking radiation" on Wikipedia)

The hawking radiation from a galactic sized black hole is negligible.

As matter falls into the black hole, it gets superheated and radiates lots of EM.

Indeed, that's my point. One the black hole has cleared its surroundings to the point where it's no longer growing, then the radiation emitted from this source will drop until it starts growing again.

Re:Where does the energy come from? Hmmm?

[Urkki]

Indeed, that's my point. One the black hole has cleared its surroundings to the point where it's no longer growing, then the radiation emitted from this source will drop until it starts growing again.

But the expelled matter doesn't magically fall back. The matter that didn't fall in was forced into a stable orbit around the galactic center by the radiation pressure. There'd be only random wandering stars that by chance get too close to the central black hole in their orbits. But even a galactic black hole is a tiny tiny dot in the center of a galaxy, so these unlucky stars would be few and far between.

So in practice the black hole stops growing in a galactic environment. It could grow if it got some mass, but it just can't get that mass from anywhere. A star per millenium (or whatever) doesn't do much for a black hole this big, not even in cosmological time scales.

Or that's how I understood it. I could be wrong.

Re:Where does the energy come from? Hmmm?

[argent]

But the expelled matter doesn't magically fall back.

It's not magic, it's just turbulence. "Orbits" in a galaxy aren't ever going to be stable over cosmological time scales... and the ring outside the empty zone is still the densest part of the galaxy. It's going to spread out and flatten until the average density around the black hole starts increasing again, no?

Re:Where does the energy come from? Hmmm?

[Urkki]

But the expelled matter doesn't magically fall back.

It's not magic, it's just turbulence. "Orbits" in a galaxy aren't ever going to be stable over cosmological time scales... and the ring outside the empty zone is still the densest part of the galaxy. It's going to spread out and flatten until the average density around the black hole starts increasing again, no?

Well, if the article is correct, then apparently not. As far as I understand, the growth would have to be very slow, or the radiation pressure would blow the rest of the matter away and again stop the growth.

Also, once the immediate vicinity of the black hole is empty, it's sphere of influence is really very small in galactic scale. Anything falling towards it would have to hit it quite exactly, or it'd just zip past it without getting sucked in, and then perhaps make another pass in a few million years, again probably missing it. The neighborhood of the black hole would be rather empty, everything either having fallen in or been blown away by the earlier radiation, so there wouldn't be much resistance either. And any occasional star getting ripped apart by the black hole would create a burst of radiation that would keep the vicinity of the black hole clear of gas and dust.

Something like a merger of galaxies might create brief periods of faster growth, giving the black hole new mass to swallow. But again the radiation pressure would blow most of the new matter away quickly, so compared to the total mass of the black hole, the relative growth would be very little.

Re:Where does the energy come from? Hmmm?

[John Hasler]

> And any occasional star getting ripped apart by the black hole would create a burst of
> radiation that would keep the vicinity of the black hole clear of gas and dust.

So the growth doesn't come to a complete and absolute halt: it just becomes imperceptibly slow.

We need to find the ANCIENT TIME-LOOP DEVICE

[Joe The Dragon]

To control the loop.

Re:We need to find the ANCIENT TIME-LOOP DEVICE

[Anonymous Coward]

Loop control found:

for (i = 0; i < MAX_UNIVERSE_SIZE; i++) { universe.expand(); }

Re:We need to find the ANCIENT TIME-LOOP DEVICE

[LordSnooty]

Ahhh, but who or what defined MAX_UNIVERSE_SIZE?

Growth not forbidden, merely altered

[SleptThroughClass]

The proposed situation does not forbid the growth of black holes, it merely suspects that the usual supply of material may be lost. Basically, the infalling material may become so energetic that it explodes outward and pushes away the interstellar dust and gas. However, anything which gets close enough to the black hole will still be pulled in. Growth of the black hole is not forbidden. Gas and dust which escapes "nearby" stars will still fall in, as will any stars which pass too near. The proposed mechanism would only block growth if any particle or photon which approaches the black hole will be so excited by the approach that it gains enough energy to escape before reaching the event horizon. This also requires that when an accelerating particle heats up and emits radiation, any infalling radiation also is accelerated and escapes. Nothing in the summary of the process indicates that the process affects all infalling material, only an effect upon some surrounding material.

Real limits on black holes

[ziani]

Personal experience has shown that black holes expand to about the size of a corporate accounting department.

They may actually be one and the same thing.

UPPER BOUNDS OF BLACKHOLE!

[Windows_NT]

Bill Gates found it in the 80's:
640K!

A Cosmology Geek jokes...

[wild_berry]

Always has been, always will be, and goes through periodic cycles of growth and destruction, without end

So overall you're a steady-state cosmologist. I assume you were quite perturbed by the emergence of Big Bang Theory?

This is what they needed cray for?

[moniker127]

All of those super computers they use for these sorts of calculations....
I think the scientists just use the crays to play 4000 instances of world of warcraft at once, and they just phone in the results of "oh, yeah, blackholes can only get really really big" "how big can they get?" "Umm... like... a hundred billion.... STARS."

Self evident

[Perdo]

After the discovery that all galaxies had a super massive black holes at their cores, it was obvious that black holes had an upper size limit, since there are no universe spanning super galaxies.

The discovery is about the mechanism of this fact, not the fact itself.

Blackhole Weapons

[kmahan]

Farscape covered this at the end. Just ask John Crichton.

Brigadoom

[HTH NE1]

Well, if you think of it as time being a loop, then there is no time outside of time (er...) and once it ends, it is back at the beginning again and starts over.

"Time begins, and then time ends,
And then time begins once again.
It is happening now, it has happened before,
It will surely happen again."

What if 2 collide?

[Anonymous Coward]

So what happens when 2 black holes, each at their size limit, happen to collide with each other?

What if two converge

[WarJolt]

What if two black holes converge? Then I bet it would be one giant super black hole of death.

Are you sure?

[Neanderthal Ninny]

I have a larger black hole larger than that, the one that our politicians and financial people are.
That black hole sucked all of our money (the key word here is OUR money) in.

Local redistribution of light gases.

[Randomly]

For reasons not fully understood, it appears that the sizes of central black holes and the masses of their galaxies, especially the central bulges, are almost perfectly in step.

Is it therefore safe to assume the black holes are only redistributing gases within each galaxy?

IANAAP, even so I wonder, if gases are being forced through the centre of black holes in some form, through four or more dimensions, what is the net 'jet' effect on the direction and velocity of the galaxies?

Well, that's certainly a relief.

[IWood]

I'm glad they reined those things in.

What if there is no gas?

[sugarmotor]

What if there is no gas? What if just one lollipop drops into the black hole every hundred years? Would the black hole then reach a limit "No more lollipops, please" ?

Oh well,

Stephan

Re:What if there is no gas?

[John Hasler]

Even a ten-billion-sun black hole probably emits more than a lollipop's worth of Hawking radiation in a hundred years. Thus fed only on one-a-century candies your black hole might actually shrink.

HHTTG knew this ages ago...

[Falconhell]

Ford Prefect; So do you know how the universe was created?

Arthur; "No"

Ford Prefect: "First, you get a large Ebony bath"

Arthur; "Where from, Harrods was destroyed by the Vogons"

Ford; "It doesnt matter"

Arthur; "So you keep saying"

Ford "Anyway, put the plug in and fill it up with fine white sand, then pull the plug, but you film it, then play the film backwards and everything seems to swirl up out of the plughole.

Arthur; "And thats how the universe was created?"

Ford; "No but its a marvellous way to relax" (-:

Time Dilation

[Maltheus]

Anyone know how close the surrounding gas would have to be before it would appear to stop swirling from our perspective? Or is it moving so fast that time dilation wouldn't appear to have much effect. Would the gas that gets blown away actually appear to speed up as it gets further from the black hole?

hot enough to evaporate a sun

[budgenator]

If something denser, like a star were to fall in, I doubt that the radiation pressure would push it away.

I was thinking the same thing but if you heat a star to a 100 million degrees I doubt it would stay star-like. Something hot enough to evaporate a star, now that would be some shit to get your head around, it might look like a comet only in x-ray instead of visible light. A neutron star or another blackhole might do the trick; another neat effect might be pulses of gas being expelled at near light speed as star get crushed and get heated up in pulses as the fall into the surrounding vacuum.

Black hole (sucking in a) sun...

[aisrael]

If something denser, like a star were to fall in, I doubt that the radiation pressure would push it away.

IANAAP either, but while we're speculating from our armchairs -- unless that star were dense enough on its own wouldn't it break apart (into its component gases) as it reached the black hole's Roche limit?

In fact, the article itself states:

Their quasar-pumping conversion of matter to outward-beamed energy as they consume gas, dust and the occasional unlucky star...

Maybe a neutron star would fit the bill, or another black hole -- but the article doesn't take either into account.

Engineering Notation

[Anonymous Coward]

In engineering notation, the exponent must be a multiple of 3.

The idea of a black hole made of gold is kind of funny. If you find one, be sure to help yourself to the gold inside.

LOL

[cyn1c77]

It is questionable if it is acceptable to do so if they are end-term on a horrific disease, due to the chance of recovery.

The girl in India thought that she was at the end-term of humanity with zero chance of recovery. According to what she knew, even your definition makes her suicide acceptable.

The girl was 16 and her parents tried to convince her it wasn't true. It sounds like she had other problems and the LHC was just an excuse.

I get a kick out of her mentality though, some act of nature might kill me, so I kill myself first... Natural selection for the win there, IMO.