Black Hole Sans Donut Puzzles Astronomers

Anonymous Squonk writes: "This time, a telescope made news by not finding something. According to this Honolulu Star-Bulletin article, a black hole was found that did not contain the expected 'donut' of warm matter swirling around it. This discovery (or lack of discovery) may lead scientists to rethink what they know about the core of active galaxies."

Comments

viva la homer

[banditski]

(as homer is sucked into said blackhole)

mmmm.... intergalactic donut...

d'oooooooohhhhhhh!!

Re:viva la homer

[jeffy124]

From the episode of Mensa taking charge of Springfield:
[steven-hawking]Homer, your theory of a donut shaped universe is intriguing[/steven-hawking]

Re:viva la homer

[Gkeeper80]

correction. he says

"crapcrapcrapcrapcrapcrapcrapcrapcrapcrapcrapcra pc rapcrap...."

Re:viva la homer

[Anonymous Coward]

Redundant!? It's the very first real post!! I actually see that post as Funny

Re:viva la homer

[Zenjive]

Doh! I knew I should have listened to that wheelchair guy!

Not necessarily

[Apotsy]

A black hole without the "doughnut" of hot matter is not in conflict with current theory, if it is massive enough. Read Kip Thorne's "Black Holes and Time Warps" and notice the description near the beginning of a hypothetical massive black hole called "Gargantua". It is so massive that its event horizon is far enough away from the center so that the tidal forces are not enough to produce the large, flattened disk of hot spiraling matter.

The article doesn't say, but perhaps the reason they are puzzled is because this black hole is thought to be far less massive than Thorne's hypothetical "Gargantua". Nonetheless, the lack of a so-called "doughnut" is not necessarily in conflict with current theory.

Re:Not necessarily

[MousePotato]

good points and thanks for the tip on the book.

My theory, albeit an unedumacted one, is that this may be a wormhole rather than a classic singularity/core type. The terms may be wrong but I think you get my idea of it being a conduit to another point in warped/folded space versus a "crush everything it can suck in to some insanely massive yet small space" type of black hole. All we need to do is look to see if there is an 'other end' to it.

This may be one of the coolest discoveries yet :)

Re:Not necessarily

[mmontour]

A black hole without the "doughnut" of hot matter is not in conflict with current theory, if it is massive enough.

But according to the article, this black hole *does* have the hot accretion disk (as well as a huge jet blasting out of it). The missing "doughnut" is cooler matter (emitting in infrared, not X-rays) that they expected to find around the disk.

I think (but I'm too lazy to check) that there's a picture in the Kip Thorne book you mentioned showing a few possible theories for what the gas around a black hole could look like, with a variety of electric and magnetic field patterns. So this "no doughnut" observation will probably help to refine those calculations, but I don't see it overturning any fundamental black-hole concepts.

Re:Not necessarily

[kaimiike1970]

I believe that is spelled 'edumacated'.

Gemini's website

[thesolo]

Is actually here: http://astra.hi.gemini.edu/gallery/science/m87/

wheee

[smaughster]

>>This discovery (or lack of discovery) may lead scientists to rethink what they know about the core of active galaxies."

ermz, isn't this the essential part of science? Every astrophysic I know is among the first to admit that the current theories are still based on several large assumptions, and can are turned over every once in a while. This makes it one of the most exciting parts of science since there still is lots of new things to find out and do. So next time, replace the word may with should or will. :)

Or perhaps

[alnapp]

If its a very big black hole, its a really big Donut and they just need to zoom out a bit.

Just a theory

Is it my imagination...

[tonyc.com]

Or has almost every astrophysics-related story I've seen lately included something like "this discovery will force scientists to rethink everything they know about [insert specialty here]?"

Is this a requirement for continued research funding? Or is our understanding of astrophysics in general so incomplete that none of our theories form a coherent system that can stand the addition of even one more observation?

Re:Is it my imagination...

[Jace of Fuse!]

It's not your imagination... it's just further proof that everything everybody knows is wrong.

Re:Is it my imagination...

[Lowther]

It isn't your imagination. Astrophysicists don't know - they are making a best guess on the limited information they have available. Just a matter of a few hundred years ago, we were prepared to throw a man in jail because he declared his belief that the Earth circled the Sun, and not vice versa. At that time it was also a matter of debate as to whether the planet was a sphere (or oblate spheroid even), or whether it was flat. And we were living on it at the time !

Given the fact that our technology will only allow us to venture a miniscule distance from our planet in universe terms, and achieving more will take centuries (if we survive that long), and at best we can observe but a miniscule fraction of it from our planet, and it is supposed to be growing, it follows that we know nothing of the universe, and this will not change in our lifetimes or our children's.

And yes, massive amounts of funding are tied up in this exploration. We need to explore the universe. But if the astrophysicists said "Well chaps, we have looked into the skies for centuries, spent trillions on manned and unmanned missions, and, to tell the truth, we still know jack s**t", I suspect the funding would dry up. It is better for them to present each new discovery as something which enhances and expands our comprehension, and challenges our hypotheses, rather than admitting that in real terms, we still know nothing about the Universe and how it works.

Re:Is it my imagination...

[ChenLing]

Of course, teasers such as "New Data Collected by Astrophysicists Confirm Current Theory -- Story at 11" just doesn't cut it.

There are experiments every day that confirm and/or expand our understanding of the universe. However, the only "newsworthy" items are the ones that are either really new and interesting; or conflict current theories to a large degree. For the other "discoveries", you have to read scientific journals, and not the Honolulu Star. :)

Re:Is it my imagination...

[MrFredBloggs]

Yeah, and the universe is far older than previously thought, scientists announced today. Another classic they wheel out every 6 months or so.

Re:Is it my imagination...

[Blackneto]

It's also proof that once the answer is found, The question will change and make it invalid anyway.

Re:Is it my imagination...

[darkonc]

Of course, teasers such as "New Data Collected by Astrophysicists Confirm Current Theory -- Story at 11" just doesn't cut it.

Seven thousand images were takent today, and they chose the one wierd one to put on the front page.

Re:Is it my imagination...

[ozbird]

Is it my imagination... Or has almost every astrophysics-related story I've seen lately included something like "this discovery will force scientists to rethink everything they know about [insert specialty here]?"

It's not your imagination:

"There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened." - Douglas Adams

Seriously(?), it probably simple bias - stories like "Scientists find what they set out to discover" just aren't newsworthy, unless the subject matter is newsworthy/wacky/humourous e.g. "Why shower curtains billow inwards."

Gravity sucks; black holes really suck.

Re:Is it my imagination...

[Rasta Prefect]

Actually, no it hasn't. In fact I believe the one just two stories down the front page about dark matter measurement...

Secondly - Of course every story you see is about some measurement that upsets our current theories about something. If they simply took yet another measurement that confirmed that yes, we pretty much understand this, it wouldn't be news, would it? Hence, we only hear about the ones that change things, cause it's more interesting to those outside the field.

Re:Is it my imagination...

[Geeky Frignit]

Come on, this is the /. community. Would you rather them collect all this new information and keep it to themselves?

Re:Is it my imagination...

[Ctrl-Z]

It could still be considered a matter of debate as to whether the Earth is round or flat.

Re:Is it my imagination...

[Anonymous Coward]

Well, for the sake of argument...

The "ether factor" and "maintaining speed" objections are based on pre-Einsteinian assumptions. "But light waves would still require a medium for transmission, and the actual purpose of the [Michelson-Morley] experiment was to determine the existence of that medium.") However, there is no such requirement, as Einstein showed, and furthermore no experimental evidence for the existence of such an ether.

The "accelerating world" objections are based on an ignorance of free-fall physics. Astronauts gravitationally accelerate in a circle about the Earth, but they are not hurled away.

The "staying on top" objection is so absurd that I am amazed. They don't seem to know that the gravitational force is centrally attractive, not oriented in one particular direction (such as "from the North to the South poles").

In the "falling off" objection, they suddenly seem to realize that gravity isn't supposed to work the way they think it does. They attempt to dismiss it with vague handwaving about "alignment of gravitational charge". I have no idea what this means; if you drop an object, it falls immediately. It doesn't sit around and "align" with anything.

"Negotiating long-distance travel" still ignores the central nature of gravity. The local gravitational pull depends on location; someone at the North pole doesn't carry around a "down direction" with him, he is merely pulled down towards the center of the Earth no matter where he is or was originally.

The "fluid problem" is based on the same bizarre arguments, and "thermodynamic complications" aren't even justified.

Re:Is it my imagination...

[Anonymous Coward]

Of course, I might also add that "for the sake of argument" is self-amusement, as somehow I doubt that the authors really believe in rouge hamster insurrections...

I have been bitchslapped, and must use another ip!

[Anonymous Coward]

It's not really surprising that some black holes don't match the canonical form. They draw the matter in the torus from the surrounding galaxy, so any galaxies with unusual properties would affect the black hole. The article doesn't give many details about the M87 galaxy or how much research has been conducted on it, and since noone bothered to look for a black hole torus in it before, there may be other related phenomena yet to be discovered.

Is inference an art?

[imrdkl]

When I read stuff like this, I really wonder about the reliability, feasibility, and especially the beleivability of inference based on observations (or inference from the lack of observation). Consider a couple more..

• Wobbly suns mean planets are orbiting around them, even though they cant be seen. Maybe they just wobble once in awhile. I know I do. ;)
• The universe keeps getting older, because we know exactly how light behaves over time and space. What happens when we invent yet larger and/or more powerful telescopes? Will galaxies continue to be found which are further and further away?
• The moon must only be about 5-10 thousand years old, since it only had a half-inch or so of dust on it, uniformly and consistently.

I'm no physicist, and probably should just be reading this thread from afar, but I cant help wondering about these "inconsistencies".

Please dont lecture me about the scientific process, I do respect the work and effort of those who would know answers to these sorts of questions, but once again they must revise their theories, it seems.

Perhaps cosmological inference is simply faith.

Re:Is inference an art?

[IngramJames]

Oh, boy, will you get flamed!

But not by me. I'm nowhere near a pro, but even I recognise the huge faws in your arguments.

Wobbly suns mean planets are orbiting around them, even though they cant be seen. Maybe they just wobble once in awhile. I know I do. ;)


Nothing moves without a force being applied to it. If there is no force, there is no motion. In your case, the force is alchol and gravity. In the case of a star it must be gravity, unless there's some really bizarre other force as yet undiscovered. However, since our own sun wobbles in accordance with the laws of gravity, as do the planets with moons, it's pretty safe to assume other stars are acting under the same forces.
There are also other methods of detecting extra-solar planets.

The universe keeps getting older, because we know exactly how light behaves over time and space. What happens when we invent yet larger and/or more powerful telescopes? Will galaxies continue to be found which are further and further away?

Up to a point. You never read "A Brief History of Time", did you? :) Better telescopes will only reveal older galaxies, further away up to the point where galaxies were first created. Once you get to that point, you can't see new galaxies, onlythe material from which they were formed.. which probably will be undetectable. And this assumes, of course, that the earliest galaxies gave off light and radiation which has not been blocked by an object between them and the Earth (say a younger galaxy in our own cluster). It also assumes that the radiation is strong enough to be picked up.. it's travelled an awful long way and it may be impossible to detect no matter how sensitive the device.

The moon must only be about 5-10 thousand years old, since it only had a half-inch or so of dust on it, uniformly and consistently.

This article should cover pretty much everything there. Here's a brief quote:

Even though the creationists themselves have refuted this argument, (and refutations from the mainstream community have been around for at least a decade longer than that), the "moon dust" argument continues to be propagated in their "popular" literature, and continues to appear in talk.origins on a regular basis

So you've fallen foul of a popular myth propogated by some Creationists. Took me 2 minutes to find that article using Google and a search for "age of the moon".. please do some basic checking of this kind of thing.. propogation of ignorance is not a good thing.

Re:Is inference an art?

[imrdkl]

Thank you for taking the time to "set me straight". I did not intend for my post to be FlameBait, although, as you point out, there is plenty of scientific refutation to my points.

But (you knew this was coming, right?), my points stand. Each of your refutations are legitimate, but each is also subject to the same bias which gives rise to their original claim. Namely, inference. (also the title of my posting)

The talk.origins faq especially, was interesting, in that it concludes that a sample taken from the top of a mountain is equivalent to one taken in the vacuum of space, and then goes on to say that the maximum amount of dust that could possibly have collected on the moon is some 64cm. Which is exactly 64 times the amount that I saw the lunar rover making tracks in. Perhaps a measure of collected dust on a satellite might be more realistic.

In any case, my point was not to start a creation/evolution debate, only to give my perspective on the inferential claims which have been made in the past, and wonder out loud, if such facts can ever be truth. (As opposed to faith)

Re:Is inference an art?

[Jerf]

Let's just shortcut the whole debate, OK? In the final analysis, all things are taken on faith, because none of us can be sure that our senses are telling the truth. Period.

Once you accept the reality of the outside world, if indeed you do (and if you don't, you might as well 'stop reading' now, inasmuch as that has meaning), you can reason about it.

While we can never make statements with 100% confidence, I'm certainly vastly more confident about "A large mass, which can only be a planet (basically, the definition of a planet is "a large mass in orbit around a star" (though there's more of course), is causing the star to wobble", then whatever other explanation you can come up with.

"The star wobbles for no reason, in flat contradiction to every other observed behavior of physical objects"? Sorry, that doesn't rate highly with me.

You make the classic mistake... that because nothing is 100% certain, all things are 0% certain. The logic doesn't hold; there are middle grounds, certainties between 0% and 100%, and as soon as that is true, the "either-or" breaks down. And you are thrust, kicking and screaming, back into the world the rest of us inhabit, where you actually have to decide, and act upon, what you believe to be true.

Personally, I recommend continuing to act as if gravity and intertia are true. It gets messy when you try to deny those things. I'd link the rotton.com pictures but that's probably just mean... besides, I don't particularly like looking at them.

Re:Is inference an art?

[buckeyeguy]

There are slight variations in the way the Sun moves and rotates, mostly due to the fact that it is not a rigid body, but rather a big ball of gas (very densely packed gas, to be sure). Variations of the magnitude that would be observable across light-years of space, however, can only be credibly explained by orbital (read: companion body) interaction.

And the dust argument... sheesh... Q: what happens to particulate matter of most any sort when it sits long enough? A: it accretes to the solid surface around it. Result: it is no longer dust. The depth at any given point could be attributed to the rate of addition of the particulate, minus the rate at which it accretes and leaves the 'dust' state.

Never much liked talk.origins... it's misnamed, it should be talk.beliefs instead.

Re:Is inference an art?

[Bobo the Space Chimp]

> In your case, the force is alchol and gravity.
> In the case of a star it must be gravity, unless
> there's some really bizarre other force as yet
> undiscovered.

Pangalactic Gargle Blaster.

Re:Is inference an art?

[Anonymous Coward]

But (you knew this was coming, right?), my points stand. Each of your refutations are legitimate, but each is also subject to the same bias which gives rise to their original claim. Namely, inference. (also the title of my posting)

Yes, and maybe I'm just a brain floating in a vat somewhere being fed sensory input, and you don't really exist. That doesn't mean it's likely.

Nobody can absolutely prove anything to be "true" in our universe, because all proofs rest on postulates which are themselves unproven. However, that doesn't make it credible that if I drop a ball, it will suddenly fall up. There are many things that we can state with great confidence (if not total certainty), based on a wealth of empirical data.

(Incidentally, that doesn't mean that we "take them on faith", in the sense of believing them to be incontrovertible. I can believe that the Sun will rise tomorrow, without claiming that it's impossible for the Sun not to rise tomorrow. There is a difference between belief and faith.)

Re:Is inference an art?

[Yunzil]

and then goes on to say that the maximum amount of dust that could possibly have collected on the moon is some 64cm. Which is exactly 64 times the amount that I saw the lunar rover making tracks in.

So, if you go to the beach and sink 1 inch into the sand, then the sand must be only 1 inch deep?

Re:Is inference an art?

[imrdkl]

Jerf writes:
I'd link the rotton.com pictures but that's probably just mean... besides, I don't particularly like looking at them.

Ouch. Look, I'm just as confused or more as anyone else. I'm also a newbie and trying to sound important. heh. No hard feelings, I hope.

No wait...

[Anonymous Coward]

I think they're confusing real life with TV again - this happened in StarGate on TV last night.

All you need to do is cause an energy surge to make the wormhole jump from one gate to another, simple. job done. no more black hole.

This is about torus, not the disk

[Caid Raspa]

\begin{rant}
If you see 'theory + astronomy + black hole' this does not automatically mean theory==relativity.
RTFA
\end{rant}

It is so massive that its event horizon is far enough away from the center so that the tidal forces are not enough to produce the large, flattened disk of hot spiraling matter

The 'flattened disk' you refer to is the accretion disk that is easily seen in M87. For example, the X-ray spectrum would be completely different if there was no disk.

The 'doughnut' or torus is a cloud of cool matter, that is feeding the disk. It is about just as 'flat' as a real doughnut. Generally the torus of an average active galaxy is far enough from the black hole to make all relativistic effects insignificant. Relativity is very important at the inner edge of the accretion disk, where the disk meets the event horizon. However, this is literally light-years from the torus.

Now, the astronomers can not see the torus. This means that the matter fed to the black hole is almost finished, and should not be able to power such a bright accretion disk. I believe this is the 'problem'.

Either the accreted matter comes from some unknown source, and/or some mechanism makes the accretion disk brighter than expected. Thus theoretical problems are more probably related to galaxy evolution and/or accretion disks. These are both rather ill-understood issues when compared to general relativity.

SANS Donut?

[Demerara]

What has a black hole got to do with System Administration and Network Security?

Am I missing something here?

And, surely, it's "doughnut"?

Re:SANS Donut?

[kaimiike1970]

Actually, both spellings are accurate.

donut

doughnut

And now for the obligatory Simpson's ref.:

Mmmmmmmmmmm, donuts.

Re:SANS Donut?

[Anonymous Coward]

Only an American wouldn't know that sans is French for 'without'.

Astronomers are always being surprised

[Anton Anatopopov]

It seems that the more we learn about our Universe, the less we can be certain about it. I remember when they first detected the background radiation from the 'big bang'. That was a big upset because it wasn't behaving how astronomers thought it should.

Then there was the whole 'dark matter' brouhaha. It seems to me that Astronomers need to formulate some new models of space and time, to account for all these anomolies, Perhaps professor Stephen Hawking holds the key to this...

Re:Astronomers are always being surprised

[DullTrev]

Well, of course astronomers are always being surprised. This field, which essentially relates to observational cosmology, is incredibly young. Observational cosmology only really started with Hubble (the man, not the machine...). When you think of how long other sections of physics have been going, this is a minute amount of time.

Astronomy itself is ancient, but this has essentially been only data-collection, rather than trying to understand the processes. It has been more like botany than biology - a taxonomic exercise rather than a science. Now we have the instruments so that theories we formulate can be tested observationally, so we are bound to have a lot of theories lost along the way.

Remember, only a hundred or so years ago, we thought the sun was acually combusting - burning some fuel in a chemical reaction with oxygen! Don't be surprised if theories change - perhaps we are missing some fundamental information. In fact, most cosmologists would say we definitely are - they know that the present system of physics we have breaks down in 'extreme' situations. And a black hole most definitely counts as extreme.

Re:Astronomers are always being surprised

[Anonymous Coward]

I remember when they first detected the background radiation from the 'big bang'. That was a big upset because it wasn't behaving how astronomers thought it should.

Really? It behaves pretty much the way theory had predicted, though the original experiments weren't terribly sensitive. What exactly are you referring to?

Re:Astronomers are always being surprised

[Anonymous Coward]

Don't be surprised if theories change - perhaps we are missing some fundamental information. In fact, most cosmologists would say we definitely are - they know that the present system of physics we have breaks down in 'extreme' situations. And a black hole most definitely counts as extreme.

True enough, but I'd say that the result being discussed here probably says a lot more about what we don't understand about galactic dynamics, rather than what we don't understand about black holes.

IT's the ATI

[Stephen Samuel]

It's that damned Anti Terrorism Initiative. We've got so many cops now, that they're reduced to eating the donuts from remote galaxies on their break time.

Maybe

[mrfiddlehead]

Maybe it's an anti-blackhole. Kewl.

Gump said it best, "stupid is as stupid was"

[f00zbll]

We humans have a tendency to think we are smart and know how the physical world works. That is until some scientists come across a phenomenon that counters current theories. The last time I checked, science defines/accepts theories as laws after a sufficiently long test period. Once the theory is put to test and proves to be better than other theories, it is accepted as a physical law. One important fact people tend to forget is everything we based on observable information. There are numerous phenomena we can't observe or are beyond our abilities, therefore all theories are subject to a large margin of error.

Statements like "this will change how scientists think about x" really shows how self centered our species are. I find the scientists' reaction far more interesting than the fact there is no donut around the blackhole.

Maybe it's shy :p or it let his neighbor borrow his donut.

Re:Gump said it best, "stupid is as stupid was"

[Anonymous Coward]

Once the theory is put to test and proves to be better than other theories, it is accepted as a physical law. One important fact people tend to forget is everything we based on observable information.

Scientists don't forget it, at least -- the whole point of what they do is to either discover something new or provide more evidence supporting an existing theory. If the theory was assumed to be right, there would be no point in any of that.

There are numerous phenomena we can't observe or are beyond our abilities, therefore all theories are subject to a large margin of error.

I wouldn't go that far. When new phenomena reveal new theories, it doesn't mean that all our old theories are hugely wrong. They still work extremely well for the old phenomena. Good theories don't die, they just become limiting approximations to better theories.

Statements like "this will change how scientists think about x" really shows how self centered our species are.

Really? Would you prefer that they not change how they think about something, when presented with new data? Seems to me that would turn science into mere religion.

I find the scientists' reaction far more interesting than the fact there is no donut around the blackhole.

What, you mean admitting that they don't understand something? Why is that interesting?

Re:Gump said it best, "stupid is as stupid was"

[dangermouse]

That's the way it's supposed to work. If you haven't already, give Thomas Kuhn's The Structure of Scientific Revolutions a read.

Re:Gump said it best, "stupid is as stupid was"

[Recolada]

Too bad he actually said "Stupid is as stupid does."

Sans Donut

[loconet]

Is that a new font type for X? where can i get it?
any links?

No one told me about any doughnot theory?

[Tyler-Durden255]

No one told me about any doughnut theory therefore I'm not very troubled...

What are the precepts of this theory anyway? That because we see some matter spinning along a plane in an accretion disk there must be other matter doing about the same thing outside it?

Or is this one not even an actual theory but a failure of matter to behave the same as a simulation.

Anyway M87 is an elliptical galaxy, those typically have stars orbiting around there center every witch way not along a flat plane like out spiral galaxy. Why to we expect to see a plane of accretion around the center? because the Black hole MUST have had some angular momentum and transfers it to surrounding matter via tidal and gravitational force? because water always swirls down the drain? Why can't there be an elliptical acceleration area around a black hole that is 3D and not flat?

Mystery solved...

[Anonymous Coward]

Earlier today it was announced that the astronomers forget to turn the telescope on. Commented one astronomer, "We never really thought about that, I mean, black holes are supposed to be black, right?"

Blah!

[Caine]

When will they stop fooling around with this kind of lame stuff, and give me hyperspace or warpdrives. I'm getting restless!

Re:Blah!

[Anonymous Coward]

Warp drives? You heard of special relativity yet?

Going faster than 300,000 km/h is NOT allowed!

(and that is definitely absolute, unless you have an greater-than-infinite [ie imposssible] energy source)

And before you mutter something about wormholes, don't forget a) they're purely theoretical b) there is no way of producing one c) there is no way of stabilising one d) travelling through one would kill you.

Seriously, FTL/wormholes is fantasy, just like nanotech, teleportation, true AI etc,. You can come up with all the theoretical designs you like, but we are unable to manipulate energy at those magnitudes and it is unlikely that we we ever will be able to. But people take Sci Fi seriously, and they think something like this will actually be created one day. Yeah, right. Whatever.

Re:Blah!

[Caine]

First of all, it wasn't meant as a serious comment, and second of all, as you can read in this by Mr. E himself there's nothing that exactly prohibits energy from going faster.

The diameter and mass figures seem screwy

[aftersci]

About this blasted hole, I keep reading stuff like:
"Hubble Space Telescope observations have shown that at its heart is a black hole, containing the mass of about three billion stars compressed into a region approximately the size of our Solar system." (http://www.spaceref.com/news/viewpr.html?pid=6427 )

size of our solar system? we could use the mean distance of Pluto to the Sun: 5 913 520 000 km ~ 6e9 km
size of a star? the Sun is supposed to be just below average, let's just use its size. radius : (695 000 km)/2 ~ 3.5e5

volume of the Sun: 1.8e17 km3
volume of the solar system: 9e38 km3

you can fit 5e12 (5000 billion) of our Suns into one of our solar systems.

The mass of three billion stars 'compressed' into the volume of our solar system would hardly reach black hole densities.

What did they really mean?

Re:The diameter and mass figures seem screwy

[aftersci]

volume of our solar system 2e29 km3, sorry.

But the ratio is correct (I copied the wrong line).

Here's my calculation (I left out factors that would cancel each other out):

perl -e "\$system=(6e9)**3;\$sun=(35e4)**3;\$ratio=\$syste m/\$sun;print \"system=\$system, sun=\$sun, ratio=\$ratio\\n\";"

Re:The diameter and mass figures seem screwy

[Anonymous Coward]

According to the Schwarzschild formula (Rs = 2GM/c^2), the radius of a black hole is about 3 kilometers per solar mass. So a 3 billion solar-mass black hole would have a radius of about 9 billion kilometers. That's about 50% larger than the radius of Pluto's orbit, hence the "approximately" in your quoted statement.

What you're neglecting is the fact that a black hole is not necessarily more dense than a star. In fact, a sufficiently large black hole is less dense! For instance, a black hole of ~100 million solar masses only has an average density near that of water. It's not just how dense it is, it's how much of it you've got. Take a bucket of water, and it won't form a black hole. Take 100 million solar masses worth of buckets of water all next to each other, and they will

(I got the last example from this nice page discussing black hole myths at the bottom.)

Re:The diameter and mass figures seem screwy

[Anonymous Coward]

"Karl Schwarzschild showed that the radius of the event horizon in kilometers is 3 times its mass expressed in units of solar masses; this radius is called the Schwarzschild radius. "

radius of event horizon, not of the black hole.

Re:The diameter and mass figures seem screwy

[Anonymous Coward]

radius of event horizon, not of the black hole.

A black hole is defined to be the region of space enclosed within an event horizon, so the radius of the horizon is the radius of the hole. You're not confusing the hole with the singularity (of zero radius), are you?

special kinda black hole

[siphoncolder]

this one has an SEP field ;)

Maybe the were right ...

[Midnight Thunder]

Maybe they were right with the initial theory and someone simply forgot to take the lense cap off - doh!

I'm not impressed...

[Rui del-Negro]

A black hole without a donut...? I'm not impressed. The other day I saw something much stranger: a donut without a hole.

Re:I'm not impressed...

[Conspir8or]

> The other day I saw something much stranger: a donut without a hole

A donut without a hole is a danish. N-n-n-n-n-n-n-n-n-n ....

Re:I'm not impressed...

[kaimiike1970]

In Hawai'i we call this a 'Malasada'. So damn good. Mmmmmmmm, malasada.

House of cards?

[Daengbo]

The real issue here is that (see asteroid story above) we take a lot of conjecture, logic, and current semi-proven / popular theories, release them to the press when they aren't yet finished, and call them probable. Just because I base my outcome on six facts which I am 80% certain are right does not in any way make my result probable. What is .8^6 again? Finished calculating? Not so impressive.

Quality submissions

[BigBong]

I read Slashdot religiously every day and the Science section is the main reason. In general the Science posts to /. are great. This post was not. The article linked in this post is terrible. One sentence paragraphs comprise the entire article! Let's try to raise the bar back to where it was here people.

And in my experience...

$journal_name =~ m/(.*) star.*/i;
$tabloid = $1;

Please don't give me bad karma just because I prefer quality.

Re:Quality submissions

[Anonymous Squonk]

FWIW, the Honolulu Star-Bulletin is one of the two main daily newspapers in Hawaii, along with the Honolulu Advertiser (I'm sure you have lots of pre-conceived notions based on that name too...)

No mystery...

[Happy Monkey]

If my black hole and a donut are near each other, the donut soon is gone.

Re:If Trek has thought me one thing...

[Anonymous Coward]

That's "tachion", dumbass !!

Re:Not necessarily THIS is OT

[MousePotato]

damn... I see all sorts of moderations happening to posts, but, never for the life of me figured I'd get an 'offtopic' for that post considering it is directly on topic...

mod it down... matters not in the big picture.

No Donut?

[Anonymous Coward]

Homer Simpson will be pretty upset when he finds out about this :-) At least he still has his beer http://slashdot.org/article.pl?sid=01/10/09/224125 6&mode=thread

Re:I have been bitchslapped, and must use another

[Rand Race]

Here's some info on M87. The main thing about it is that it's freakin huge, greater in diameter than the Milky Way or Andromeda and to top that it's an eliptical galaxy so it's volume is immense compared to spirals of equal diameter. It's fairly bright with an 8.6 magnitude (extremely bright absolute magnitude of -22!) and is well studied due to it's massive number of globular clusters and the prominant jet eminating from it at apparently superluminal speed (thought to be illusionary due to the jet pointing virtualy strait at us). The galaxy is also associated with the strong radio source Virgo A. Needless to say M87 has been a popular object of study among astronomers.

Anyone else a Soundgarden fan?

[Nailer]

Or is it just me who read that Black Hole Sun .

In my eyes, indisposed, in disguises no one knows...

Honesty, credit

[Anonymous Coward]

Didn't these guys get essentially the same result four months ago?

http://www.arxiv.org/abs/astro-ph/0106381

Their biggest clue

[shanek]

The biggest clue they had was not only the lack of the donut, but the lack of police cars in the vicinity.

Re:If Trek has thought me one thing...

[kaimiike1970]

Actually, it is 'tachyon'.

Who is the dumbass now?

In Triplanetry......

[vortexau]

The Good Doc told us that Intermessing Galaxies caused all the planets!

But Niven's Puppeteers are fleeing the gamma burst from the galaxy core!

What do I think?

I think 'Storm' Cloud will eventually get rid of the Loose Atomic Vortexes!

Regards,
JK