Giant Black Hole Found

paradox writes "Reuters is reporting that scientists have found a massive black hole 40,000 light-years away that could change the way scientists think about black holes. The mass of this particular black hole is 14 times the mass of the sun, compared to the typical mass of 3 to 7 suns."

Scientists should really...

[tcd004]

Scientists should really leave rosie o'donnell alone.

tcd004

non-watered down story

[ChazeFroy]

Here's a link [eso.org] to the European Southern Observatory story that's not watered down (gotta love Reuters and AP like that!).

Kill It!

[bcilfone]

Destroy it before it kills us all!

Re:Kill It!

[praxim]

I prefer the Half-Life version, which is, I believe, "Destroy the damned thing before it grows any larger!"

Why the puzzle?

[Mt._Honkey]

Is it so odd that a stelar black hole formed, and maybe driften near a cluster of stars or a big ass nebula in its lifetime? Maybe it's ancient.

Size IS important.

[ho11yw00d]

But what about its physical size? I mean, when you are dealing with monstrous astro-physical phenoms beyond human comprehension, isn't it important to be boggled by the density?

Re:Size IS important.

[zCyl]

But what about its physical size? I mean, when you are dealing with monstrous astro-physical phenoms beyond human comprehension, isn't it important to be boggled by the density?

Because there IS no size. A black hole by definition is a singularity, and has no conceivable dimensions. The closest thing a black hole has to a size is what's called the Schwarzschild radius, or the event horizon. This radius is the distance from the center at which light can no longer escape (ignoring Hawking radiation, another topic entirely). The Schwarzschild radius is equal to 2GM/c^2, where G is the gravitational constant, c is the speed of light, and M is the mass of the black hole. So the radius is really nothing more than a constant times the mass.

If you know the mass, and you don't have rotation, you know everything that can be known about it.

Re:Size IS important.

[Unknown Poltroon]

I beleive you can know the charge also, positve or negative.

Re:Size IS important.

[the_2nd_coming]

no a sigularity is the center of a black hole, it is where space time becomes undefind. a black hole is the defined by the eventhorizon. so it does have a size. if it is just a sigularity it is not a black hole, it is a naked sigularity.

Re:Size IS important.

[the_2nd_coming]

Physicly you would not have a black sphear, however, Light that is refracted around the eventhorizon would give the aperence of size. therefore a blackhole hs a diameter.

Re:Size IS important.

[anethema]

I'm confused. I was under the impression that a black hole was a star that had collapsed and the space between the electrons and the nucleus (sp?) was reduced to zero. We're always told if the earth turned into a black hole, (yes i know it cant) it would be the size of a basketball. Can someone please clarify? Im giving up the right to moderate on this story by posting this, so someone better reply :) ...

Re:Size IS important.

[rabidcow]

If it's a black hole, its density is infinite. Its physical size is zero, unless you mean the size to its event horizon, but the actual mass is all at the center.

Re:Size IS important.

[egomaniac]

A black hole is a singularity. It has no size, and therefore its density is infinite.

The sphere defined by its event horizon does have a size, but it will be very small (a few tens of miles across, perhaps). Maybe an astrophysicist in the audience will compute the size for us?

Re:Size IS important.

[sokoban]

Let's see. I found the radius of the event horizon to be about 41.8 Km. That's pretty darn huge. The formula I used was 2GM/c^2. Based on the data that the mass is about 14 Solar masses, M is roughly equal to 2.8e31.

Re:Size IS important.

[sigwinch]

A black hole is a singularity.

It's important to remember that a singularity is a mathematical artifact where a physical property has no meaningful definition when measured by a particular metric. For instance, the north pole of the Earth is a longitude singularity, a point where the very concept of longitude ceases to have physical meaning.

It has no size, and therefore its density is infinite.

Actually, that turns out not to be the case, at least not relative to our reference frame. Imagine you're a distant (and indestructible!) observer watching a star collapse into a black hole. The more it collapses, the more it is affected by gravitational time dilation: time appears to run slower for the matter in the star than for the observer. Clocks in the star slow down. Light travelling away from the star is shifted towards the red end of the spectrum.

The more the star shrinks, the more it is affected by gravitational time dilation, and thus the more slowly it collapses as measured by the outside observer. The collapse thus asymptotically approaches infinite time dilation, and appears to freeze in time to the distant observer. Its physical size at the asymptote is the size of the event horizon, a.k.a. the Schwarzchild radius.

One way of measuring the star is to ask how long it would take light to travel from its outside edge to its center, as measured by a distant observer. (Theoretically, of course, as the star would absorb any light.) Think of it as the radius measured in units of literal light years. As the collapse approaches infinite time dilation, the 'light radius' approaches infinity. This is the singularity at the center of the black hole, and is a mathematical construct arising from the distant observer's point of view. It does not mean that density or any local physical parameter is infinite

I'm deliberately ignoring what the collapse looks like to an observer inside the star. Known physics simply cannot make any meaningful predictions, except that it will never be observable from the outside (because it literally takes an eternity to occur).

Mod parent up (and other things)

[Snafoo]

Actually, I find that the interior of singularities usually has, like, a lot of blue-yellow plasma zipping around in it. Also, there are these weird five-dimensional aliens that look like your son, Dax, and Major Kira.

Re:Size IS important.

[BLAMM!]

What, African or European?

Sorry. Couldn't resist. :)

Re:Size IS important.

[cascino]

Technically the singularity itself possesses infinte density, and thus it's size cannot be resolved (i.e.: it's a single point, no matter how close you magnify it).
The Schwarzschild radius of such an object, however (better known as the "event horizon"), can be calculated fairly simply using a variation of the escape velocity formula
Rs = 2*G*M / c^2
Where G is the gravitational constant, M is the mass of the object, and c is the speed of light.
Plugging the numbers into the equation yields a radius of 2.95 * 10^6 km. Therefore this black hole has a radius just over four times the size of the sun, and an area 16 times as large. Compared to black holes usually on scales relative to that of the Earth, that's REAL big.

Re:Size IS important.

[Anonymous Coward]

Actually, speaking as someone studying in the field of quantum gravity, the question of whether singularities exist is still very much up in the air, though many people hope that Planckian physics will remove them. There are even some tentative results [arxiv.org] in that direction. On the other hand, it has been suggested that quantum gravity must contain at least "mild" singularities [arxiv.org]. So it is rather premature to claim that "most scientists" (or even most quantum gravity theorists) have abandoned the idea of a singularity.

oh, NO!

[A_Non_Moose]

First a hole in wu-ftpd and now they are in space!

Hey, that is it, a black hole is a security exploit in space.

Maximillian!!!!

Repeated story

[rjamestaylor]

Michael just posted a story [slashdot.org] about the discovery of a giant hole....

(it's funny. laugh.)

Another hole found?

[Anonymous Coward]

Specialists concur that this is hole is even bigger than the previous hole found (and also reported on /., one story back).

Although CERN tried to keep this hole silent until every God had a patch available to stuff the hole, it didn't work out that way.

It will change the way scientists think about them

[glwtta]

"We now think they are bigger!"

Distance

[gandalf_grey]

It's worth noting that the center of the galaxy is 26,000 lightyears from us, see: space.com [space.com]. So 40,000 LY is not exactly nearby, as the story seems to imply.

So, don't worry about being sucked into infinitely long strings of goo just yet.

I've always had doubts...

[fireboy1919]

...about extrapolated data.

How do we find stars and planets? We make assumptions about stellar phenomena and then predict other phenomena using those assumptions as long as they seem to work.

We do the same thing with everything we use. We've done the same thing with other stuff, but most of the time, we can observe a lot more dimensions of the data than we can with stellar phenomenon to make our predictions.

So I suggest that there are any number of reasons that could indicate why this answer makes sense: the model for detecting mass may be wrong, or the model of the formation of black holse, or somethinig else that I haven't considered.

At any rate, we have a long way to go to learn to understand stellar phenomena.

Re:I've always had doubts...

[LMCBoy]

"How do we find stars and planets? We make assumptions about stellar phenomena and then predict other phenomena using those assumptions as long as they seem to work."

Huh? We find stars and planets by stepping outside at night and looking up. What exactly are the "stellar phenomena" that we have a long way to go before understanding?

I suppose, since you're questioning the mass determination of the black hole, you must be saying that we don't yet understand Kepler's 3rd law of motion (that is the only theory needed for the measurement). Hmm...Kepler came up with that in 1609. In 400 years, his laws have been used to: construct the first accurate mathematical model of the solar system (still in use today), predict a planet beyond Uranus (Neptune was discovered exactly where Keplerian physics said it had to be), send humans to the moon, send probes to the outer planets and beyond, and determine masses of binary stars throughout our galaxy.

In short, there's nothing in this particular measurement that requires *any* understanding of stellar physics. It's a simple application of 400-year old Newtonian gravity. If you want to question the result, I suggest looking at the systematic errors of the observations (e.g., is the inclination angle of the system known? if not, the black hole could be more massive than measured).

Oh, and the process you describe (start with an assumption, make a prediction based on the assumption, test prediction by experiment/observation, refine assumption) is called the scientific method, not "extrapolating data".

Irresponsible

[Puk]

I think Reuters is being completely irresponsible by reporting this hole before a fix can be completed by all affected parties. The only current known fix for this hole is to make sure less matter falls in than energy is radiated by the hole, and keep it that way for a long time. In the meantime (however many millions and millions of years that takes), script kiddies with FTL drive capabilities will be having a field day.

Slashdot is just contributing to the problem by spreading the news. Sheesh!

-Puk

p.s. This hole is hardly a surprise. We've found that space is riddled with such holes, and to my knowledge, none of them have been closed. If space was open source to begin with, enterprising hackers would have found these holes long ago, and plugged them with Bill Gates' ego.

Re:Irresponsible

[Sabalon]

Universe Pack 2 has been out since June which fixes this hole. It is not our fault that the various gods running the universes can not be bothered to check for updates to their cosmos once in a while.

Some info

[bryan1945]

Ignoring all the obvious jokes that ACs are going to post...

14xSun is no big deal. The hypothetical central black hole in each galaxy has been ranged from 100-100,000 xSun mass, 10k being a nice round figure.

Also, considering that modern theory says that a sun needs to be anywhere from 10x to 100x our sun's mass, even considering the mass blown off during contraction, 7x sun mass is just a wrong number. 14x would be somewhere along the minimum mass to generate a black hole.

Of course, if worldwide consensus has now switched in the last 12 hours, everything above I said is wrong. Cold fusion, anyone?

Re:Some info

[JoeRobe]

14x is a big deal. The 100-100000 solar mass black holes at the center of galaxies (which still isn't proven, but has a lot of data pointing towards it) are not stellar black holes. They would be called galactic black holes. Stellar black holes are byproducts of dead stars. The Chandra limit, 1.4 solar masses, is the minimum mass that is needed to make stellar remnants collapse. If it is over 2 or 3 solar masses, then it collapses all the way into a black hole. Now, that was figured out several decades ago, so of course that number might be slightly "off," but I seriously doubt that Chandra was off by a factor of 10. I'm curious where you get 10-100 solar masses from...

When a star with a mass of ~30 solar masses or higher dies, it supernovas, blowing off most of its mass. IF WHAT'S LEFT is greater than a couple of solar masses (and within the Schwarzschild radius), then it collapses into a black hole. I repeat: it MUST ONLY be more massive than a few (2 or 3 - it's under debate) solar masses! True, the original star must be greater than ~30 solar masses; but the mass of the black hole is far less than the mass of the original star. THIS is why a 14 solar mass black hole is so strange!

By the way, NO information regarding black holes is the subject of "worldwide consensus".

Re:Some info

[coyote-san]

You're confusing two different masses. One is the mass of the star that collapses in a type-II supernova. There's a minimal size for such stars (just as there's a minimal size for a star to be a star, instead of a large Jovian body), and IIRC there's also a maximum mass due to various physical constraints.

The other mass is what's crunched into the black hole. If I remember the numbers right, and they haven't been surplanted by more recent research, at "maximum" crunch some of the stellar mass is falling inward at a third of the speed of light, and the maximum density is something like 4 times that of a regular nucleus. This is a *very* hard surface, and anything outside of the maximum crunch will be blown outward. A lot of the matter in the crunch will be blown outward, as the "spring" releases. This is the same force (under Newton's second law) that pushes the matter within this shell inward past the final resisting force and into a black hole.

All of this conspires to mean that only a fraction of the stellar mass will actually end up in the black hole. Far more will end up in the planetary nebula. But it all together and you get the usual figure of about 7 stellar masses as the maximum mass of a black hole created by a single star.

Supermassive black holes

[ukryule]

Whatever happened to the theory of supermassive black holes? [nasa.gov] These black holes, at the centre of each galaxy are supposed to be millions of times heavier than the sun.

So what's so great about a black hole only 14 times as heavy as the sun (which is also further away than the centre of our galaxy)?

Re:Supermassive black holes

[Lupus Rufus]

I don't see what's so confusing about it. This black hole was part of a binary system, with a star progressively feeding a black hole. It is an example of a relatively small phenomenon. Supermassive black holes, on the other hand, represent the cores of galaxies, and are incomparable to these "small" black holes for any number of reasons. This 14-sol black hole is new because we never knew small black holes could be so large.

Where the hell did those figures come from?

[the_2nd_coming]

black holes are not typicly 3 -7 suns in mass they are like 3-7 thousand suns in mass. a 14 sun mass black hole is very light.....I think it is spose to be 14000 suns......

Re:Where the hell did those figures come from?

[Anonymous Coward]

Not true. Most black holes form from large stars, and so are only a few solar masses. Then there are the supermassive ones at the centers of galaxies, that are millions of solar masses. We don't really know of any in between those two ranges.

Re:Where the hell did those figures come from?

[the_2nd_coming]

realy? thats counter intuitive.....perhaps the text I have read only dealt with super masive centers of galaxys and I did not read it......I will have to read a history of time and blackholes and supernovas(or what ever the second part is) again.

Re:Where the hell did those figures come from?

[the_2nd_coming]

no no the book I was refering to was Blackholes and Time warps

Re:Where the hell did those figures come from?

[aengblom]

And I quote:

"Working out the star's mass and orbit, they inferred a surprising mass for the black hole. It weighs about 14 times as much as our Sun. That's nearly twice as much as any other in a similar binary system. (Black holes at the centres of galaxies can be thousands of times heavier still)."

Re:Where the hell did those figures come from?

[the_2nd_coming]

right so this is significant because it raises the size the a small blackhole can be. right

Re:Where the hell did those figures come from?

[LMCBoy]

No, you missed the point that there are two kinds of black holes: Some are expired stars; the ones we can see have a normal star as a binary companion. Until now, these were always found to be between 3 and 7 solar masses. Others are "supermassive" black holes; we believe every galaxy has one of these at their center. These are typically more than a million solar masses.

They are both gravitational singularities, but on a hugely different scale, and the physics of their formation is totally different.

Re:Where the hell did those figures come from?

[Rasta Prefect]

Actuallly no, the majority of black holes are stellar black holes. These are created by the collapse of giant stars and are generally a few suns in mass. 1.4 being about the lower end for collapse, I believe. Take an astronomy course.

not a new discovery

[sokoban]

GRS 1915+105 has been known about for quite a while actually. It was first seen as a strong x-ray source in the early 90's. http://www.ufoinfo.com/space/shockwaves.shtml is a great article giving info about this microquasar.

we could be living in one big black hole

[goodchef]

On the subject of black holes, it's interesting to note that our entire (known) universe could be inside of a black hole. In fact, that super-black hole could be inside of a larger universe, and so on ad infinadum, or as far as you wanted to observe. conversely, since we seem to always be finding that our current "elementary" particules are in fact made up of smaller stuff. (atoms -> protons&electrons etc. -> quarks -> strings), black holes in our universes could contain entire universes within them.

Or perhaps, since the massive gravity of a blackhole would warp 4-dimensional spacetime, perhaps they lead to other unknown parts of this universe, so far away that we've never observed or discovered it. in that case, having a black hole nearby wouldn't be that bad. We'd still have to find some exotic matter or something to counteract the tidal forces, and there's time discrepancy issues to deal with, but that's a somewhat moot point.

Re:we could be living in one big black hole

[junkgrep]

---On the subject of black holes, it's interesting to note that our entire (known) universe could be inside of a black hole.---

This isn't really a good way to phrase it. "Inside" is not a concept that conveys any helpful meaning about this possibility, and in fact it sort of really confuses the issue. The basic physics point is this: it looks as if an entire universe can start from just a single singularity: that our universe could have started as a result of a quantum event. Victor Sternger has discussed this idea at length.

---We'd still have to find some exotic matter or something to counteract the tidal forces, and there's time discrepancy issues to deal with, but that's a somewhat moot point.---

Moot because it doesn't seem in the least possible? This "matter" would have be so exotic that it would be unlike any "matter" that anyone has ever even concieved of before to survive the tidal forces.

Re:we could be living in one big black hole

[LMCBoy]

"it's interesting to note that our entire (known) universe could be inside of a black hole."

Wow, groovy.

Except for the troubling lack of a singularity anywhere, and our complete failure to notice the tidal forces that should be ripping us all to shreds (how is that a "moot point"?)...

im curious...

[crazney]

how do they work out the mass of a black hole?

considering that they are so massive that the gravity causes it to be relitivly small, they can't work on size - so what do they work on?

eh?

Re:im curious...

[JetJaguar]

Except that the radius of the event horizon, even for super-massive blackholes is pretty small. Even if we could "see" the event horizon, I'm not sure there would be phenomenon happening there that would identify it as such. The event horizon is basically a theoretical construct, and isn't something that you would necessarily be able to see with a telescope, the physics gets really weird at blackhole event horizons, strange enough that nobody's really sure what it would look like, although some people have attempted to model it...

The only way to determine blackhole masses is using stellar kinematics. Either by looking at galactic stellar rotation curves (for the case of super massive blackholes at galactic centers), or looking at binary systems where the companion to the blackhole is visible, and analyzing the affect of the blackhole on the visible partner. There is no reliable way to directly measure the Schwarzchild radius.

Stellar, middle-weight, supermassive

[michaeldouma]

There are three main classes of black hole [nasa.gov]. This article relates to the "stellar" type...

Astronomers suspect that most black holes are produced when massive stars (at least 8-10 times the Sun's mass) reach the end of their lifecycle. This is a so-called "stellar black hole." Stellar black holes [nasa.gov] are the remains of dead stars several times heavier than the Sun, compressed to a diameter of a few miles or less. Supermassive black holes [nasa.gov] have masses comparable to those of a typical galaxy. These masses range anywhere from a million to 100 billion of our Suns. Supermassive black holes tend to be in the centers of galaxies, creating what are called Active Galactic Nuclei (AGNs). They may have formed in the early universe from giant gas clouds or from the collapse of clusters of immense numbers of stars. Lastly, the field of black holes, formerly dominated by heavyweights packing the gravitational punch of a billion Suns and lightweights just a few times heavier than our Sun, has another contender, the middleweight [nasa.gov] black holes, weighing in at 100 to 10,000 Suns.

Article Style?

[Suidae]

Gah! Who wrote that? It reads like a list of facts, looks like somone just forgot the &ltul&gt tags.

Those naive scientists

[BillyGoatThree]

"Reuters is reporting that scientists have found a massive black hole..."

Sounds like somebody should learn to hover over Slashdot links before clicking them...

oh man...

[SaturnTim]

oh man, that sucks...

(Black hole? Get it? Sucks? )

man, i picked the wrong week to stop sniffing glue.

--ST

Re:oh man...

[geekoid]

Soo, you ever seen a grown man naked?

article on the science journal nature,

[vikool]

here is the article on the science journal nature, it is slightly more detailed than the one on reuters

http://www.nature.com/nsu/011129/011129-13.html [nature.com]

vikas

Stop the sun now!

[piecewise]

Come, fell Slashdotters! We must stop these scientists and our fellow readers for discussing extracting kinetic energy from black holes!

Instead, we must focus on more realistic goals:

1. Building giant solar structures on top of our homes!
2. Trying to run our SUVs using corn!
3. Convince ourselves that wind mills are actually doing anything for us!

Come! Unite! Ignore the energy crisis and come up with silly ideas!

Ooh, i forgot one.

4. Believe that Americans might actually CONSERVE! Hhaahhaha!

Sorry -- it's too bad being cynical didn't produce a significant amount of energy. ;-)

Re:Stop the sun now!

[discogravy]

Sorry -- it's too bad being cynical didn't produce a significant amount of energy. ;-)

if cynicism ever actually produced energy, America would actually look forward to elections and MS products! too much to hope for...

Re:Stop the sun now!

[LMCBoy]

It's possible to extract huge amounts of energy by simply dropping matter into black holes. In fact, this is the most efficient way to get energy from matter. Too bad there aren't any nearby. Ah well, maybe we'll make one of our own someday.

Possible black hole merger?

[MetricT]

I remember reading in the literature about a survey of the masses of all known stellar-mass black holes, which led to the interesting discovery that, for reasons unknown, a majority of black holes mass about 7 Msun.

I can't help but wonder if a 14 Msun black hole is the remnant of a black hole merger. Maybe we'll be able to compare the black-hole-merger-grand-challenge problem with reality after all.

40,000 Light Years?

[BoarderPhreak]

Would that be the Delta or Gamma quadrant? ;)

Re:40,000 Light Years?

[pete-classic]

We don't discuss that outside the Empire.

Publicly available space information?

[rice_burners_suck]

This is an amazing discovery. I'd like to know what kind of equipment and techniques scientists (or should I say astronomers) use to compute the mass of things such as black holes.

In fact, I've always been interested in space, stars, planets and related subjects. If there was some software (inexpensive or even free) that allowed me to perform my own computations (perhaps using information on the net which is published by observatories or NASA or whatever), that would indeed be the coolest thing. I've searched for information like that, but I haven't found any, so I assume that space explorers down here on Earth don't make any of their information publicly available. It's a shame though.

Of course, I know of programs that have maps of the stars and whatever, but there really isn't any information on things like blue/red shifts (as an example off the top of my head).

Well all of this stuff probably requires supercomputers anyway, which is something I don't have.

Oh well.

Re:Publicly available space information?

[LMCBoy]

Actually, most of the data used by astronomers is publicly available. Try the following:

HST data archive [stsci.edu]: every HST image. Also has other mission data.

Astronomical Data Center [nasa.gov]: archive of data tables published in peer-review astronomy journals

NASA/IPAC Extragalactic Database [caltech.edu]: index of known data for other galaxies. You can get redshifts here, for example.

The software used by astronomers is also generally publicly available. For example, Debian Linux ships with IRAF, the image reduction software that most of us use (the ones who can't afford IDL anyway).

Owner of black hole sued!

[freaker_TuC]

The owner of the black hole, 40,000 light years away has been sued by the RIAA because of distributing matter against the DMCA.

DMCA 3, FREEDOM 0

The owner of the black hole takes the charge not lightly and plans to close the black hole completely leaving space and time in it's destruction. GOD 1, DMCA 0

giant hole

[ljoas]

Ok!

Who sent the goats.ex link to NASA?

/L

initial report

[vikool]

this page gives the first report of an anomaly that came about on the GRS1915+105

http://www.nature.com/doifinder/10.1038/35107019 [nature.com]

vikas

Bush

[macdaddy]

...and yet the biggest black hole competition is still left undecided. The final two contestants are "The Space Between Bush's Legs", and "The Vacum Between John 'beat by a dead guy" Ashcroft's ears".

Not a Black Hole...

[Domini]

The article mentions 3 to 7 suns begin the normal size of a black hole...

This does not seem correct.

I have been told that this would rather be described as a "pulsar".
(Dr Evil made me do it! ;) )

Anyhow, this is just my 0.02 worth of destructive critisism...
:P

Re:Not a Black Hole...

[Domini]

My friend wish to apologise:

---
The correct range for neutron stars is 1.2 - 3 solar masses and black holes
from 3 - billions of solar masses....
d
---

Black holes are not vacuum cleaners

[B.D.Mills]

From the article:

Black holes suck in everything near them including light...

This is a very common misconception, judging by the number of otherwise well-informed Slashdot readers who have been repeating this fallacy. Black holes do not suck in things any more than the Earth or Sun do. The unusual gravitational effects of a black hole are only evident for bodies that are close to the event horizon.

If the Sun was replaced by a black hole with the same mass, the planets and other bodies in the solar system would continue to orbit as if nothing unusual had happened. They would NOT be "sucked in".

Re:Potential energy source?

[Anonymous Coward]

Tell you what. You fly out there and do a complete survey of the area. We'll wait for you to come back with your findings and whatever you decide is the best course we'll implement. This is in your hands now.

Thanks for volunteering.

BTW, don't fall in! hahaha... Astronomy joke... *sigh*

Re:Potential energy source?

[Doppler00]

That doesn't make any sense. We can't actually create our own black holes (thankfully!) and the ones we know about are too far away to be any use. The only time I can think of when the gravitation of a planet is used for energy is when the gravitational pull of a planet is used to increase the velocity of a space prob.

Re:Potential energy source?

[TheOnlyCoolTim]

We're actually rather close to making our own black holes I think....

There was worry when the Relativistic Heavy Ion Collider at Brookhaven went online that among other ways of ending the World (Strangelets) or the Universe (transition to a new vacuum state), that the collisions would produce a black hole which would fall into the center of the Earth and consume it.

There was a report on the RHIC website, which I can no longer find as the website seems to have been overhauled, where they used complex maths I don't understand to decide that (a) The probability of the thing making a black hole was somewhere around 10 to the -30 and (b) even if it did make a black hole it would be a small one that would "evaporate" instead of being able to grow and consume the Earth.

There are also some good books where there are black holes in the Earth - read "Earth" by David Brin, which is entirely about a black hole falling into the Earth, and the Hyperion series by Dan Simmons is set in a future universe in which evil AIs made a scientific experiment drop a black hole into the Earth (I don't want to give out too much of the plot, but everyone thinks Earth is destroyed - they are wrong).

Tim

Re:Potential energy source?

[Robert1]

Uh, how would you make the energy? You could send something shooting into it, thus it gaining some kinetic energy, but aside from the slingshot effect it wouldn't have much practical purpose. Anything you shoot at it (if your making power) would probably need to be resent, in which case you'd have to draw it back out. Net energy gained = 0.

Only thing I can think of is using it as a giant waste dump. Launch our trash into it and let it approach the center of the blackhole for all eternity.(Gotta love time dilation)

Re:Potential energy source?

[the_2nd_coming]

actualy if we could gather the massive amount of anti-matter being shot out of it then it would be very usful as an energy source

yes you can...

[efuseekay]

it's called the Penrose process. You use it on a rotating blackhole.

The idea is that in a rotating blackhole, the minimum point of the potential moves around, so you can actually "slows" the blackhole while getting a nice angular momentum kick.

Much like how you use the rotation of jupiter for slingshot. ("gravity assist" is a bad phrase, reality is that it's "angular momentum assist")

errata

[efuseekay]

thinking a bit more, Penrose Process is nothing like the gravity assist. Sorry!

Re:Potential energy source?

[Alpha State]

In "A Brief History of Time" by Steven Hawking, radiation from black holes is discussed. Basically, they harness zero-point energy when the "quantum foam" effect occurs at the event horizon and one particle of the matter / antimatter pair is dragged into the hole. The particle that escapes appears as radiation while the trapped particle actually reduces the black hole's mass by matter / antimatter annihilation, returning the borrowed Planck energy. In this way black holes evaporate.

All you have to do to generate energy from a black hole is to harness this radiation, effectively directly converting mass from the black hole into energy. You can keep it going by dumping anything you like into the black hole.

Disclaimer: it's a long time since my physics days, there are probably a lot of errors in the above. And it's only a theory anyway. And black holes can be dangerous - please do not attempt this without adult supervision.

Re:Potential energy source?

[Fnkmaster]

Umm, how exactly would you extract that? Perhaps tidal forces can be utilized to extract power (tidal forces near the event horizon of a black hole are large, though surprisingly they are larger for a small black hole). But you can't just magically extract gravitational energy from a massive object with an r^2 gravitational field. Perhaps it's possible, but the gravity of even this massive black hole is only 14 times stronger than the Sun - so we could do whatever it is with the Sun first. I've never heard anybody propose extracting gravitational energy from the Sun, so I presume there is no easy way to do this. Accelerating particles falling inward hit an orbiting station which converts this accelerated stream into energy which it retransmits as electromagnetic waves outwards, perhaps? Sounds sort of like an artificial accretion disk - which is an interesting idea, come to think of it. Have no idea if this is at all self-consistent (much less practical).

Re:Potential energy source?

[jdrogers]

A massive black hole this close to Earth would probably be quite useful in developing high energy procedures, and also as a interstellar navigational tool, since it could be use to perform very effective "gravity whip" manoevres, such as are used by NASA deep space probes.

Well, thats all well and good, but it would still take 40,000 years for light to get there, let alone a probe traveling much slower. I think we can safely say this won't get much use as a gravity sling-shot anytime soon.

As far as an energy source, a black whole doesn't really offer much (that I know of) that any other mass out there would. I think we are better off trying to capture the energy of a much closer object, the sun. Hey, its green too, even if it is fusion. :-) The more exciting thing about this is that since it is relatively close, it will be easier to resolve with telescopes the miscellaneous things that go on around a black hole. We can learn a lot about how the universe works from watching how stuff falls into it and what things come shooting out from near the event horizon.

JD

Hello! Light-years!

[fm6]

Uhm, you do know how far away "40,000 light years" is? Assuming you could even travel that far, and find a way to tap the energ, how would you send it back? If you used a laser beam, it would take 40,000 years to get here! I rather hope the energy crisis will be over by then!

Re:Hello! Light-years!

[fm6]

Rundundant? I was first! The others are redundant!

Making stars

[Goonie]

Crazy as it sounds, I've read (in Robert Zubrin's Entering Space - a highly entertaining and thought-provoking read even if you don't agree with all of it) it might one day be possible to use black holes (though probably not ones this size), to turn supergiant planets (Jupiter size and bigger) into stars, and then inhabit the moons surrounding the planet.

Basically, it might one day be possible to move a black hole with the aid of its own gravity field and its radiation emissions. In essence stick a very large mirror in orbit round the black hole, and when the mirror is in the right position, dump some matter into the hole. When the matter gets swallowed, you get a burst of radiation which pushes the mirror in the desired direction. As the mirror is in orbit round the black hole, the hole gets pushed along as well.

Anyway, when it gets to your supergiant planet, you dump it straight in. You might assume that the planet gets swallowed straight away, but apparently the push of the radiation generated in the process limits the inflow of material to a surprisingly slow rate. Hence, the core of the planet is a lot denser and hotter, and you get fusion starting up. Instant sun, just add planets/moons/whatever, which should last for many millions of years before it gets swallowed up.

Of course, the engineering of such a mirror would be a truly astounding feat, and there's lots of other issues (not least, any convenient moons would probably have their orbits thrown in to chaos) but who knows what our distant descendants might be capable of?

Re:Making stars

[Suidae]

In essence stick a very large mirror in orbit round the black hole, and when the mirror is in the right position, dump some matter into the hole. When the matter gets swallowed, you get a burst of radiation which pushes the mirror in the desired direction. As the mirror is in orbit round the black hole, the hole gets pushed along as well

Wait, why would the hole move? seems like it might move toward the incoming matter a bit, due to mutual attraction (but not very much), and the burst of radiation presumably has an 'equal and opposite' push on the hole. The radiation pushes the mirror to a higher orbit. Seems like a way to move the mirror, but I don't see how it moves the hole. Its like a solar sail but you have to throw junk into the hole to get a push.

Re:Making stars

[Alpha State]

Think of a rocket engine - the explosion is focussed by the nozzle so that all the exhaust goes in one direction, so the reaction pushes the engine in the other direciton. The mirror would have to do the same - send a majority of the radiation in the opposite direction to that which you want to travel. This would push the mirror, presumably gravity drags the black hole along. The whole thing would be in a very precarious balance.

You could just drag the black hole with a mass and a large rocket engine, or push a mass into it - but the mirror scenario uses the black hole for power.

Re:Making stars

[Suidae]

Hmm, a giant parabolic mirror with the black hole at the focus (held beneath the dorsal guiding feathers)? All impinging radiation from the hole is redirected to provide thrust against the mirror?

Ok, I can see how that might work. Just position the non-orbiting mirror to balance the pull of gravity with the radiation pressure. Thrust is limited only by the amount of radiation you can generate. Interesting.

Re:Potential energy source?

[miracle69]

Well, regarding tapping energy from space, perhaps the best idea I've heard might possibly be the only way to make a potential perpetual machine.

Oh god! I used those words. "Perpetual Machine". Surely someone is hovering over the keys about to remind me about the three laws of thermodynamics. 1) You can't win, 2) You can't lose and 3) You can't break even. Gimme a sec here. I understand them, I assure you.

But...

The only proposal I've ever seen that might give us a perpetual machine (or practical perpetual machine, as we'd be long dead before it ceased to work) involved two fixed points at a *very* *very* large distance apart. Between these two points, you connect them by some sort of cable of unbelievable properties and have once end attached to a large expandable spool of cable, which happens to be attached to a generator.

BFD, right? Two fixed objects in the universe can't create energy.

But... we can tap the energy of the expansion of the universe by allowing the spool to feed cable (while generating electricity) as the universe expands.

No one knows if the universal expansion will be infinite or not. Should it be infinite, this would be a perpetual motion machine.

Re:Potential energy source?

[Violet Null]

Oh god! I used those words. "Perpetual Machine". Surely someone is hovering over the keys about to remind me about the three laws of thermodynamics.

Yep. =)

you connect them by some sort of cable of unbelievable properties and have once end attached to a large expandable spool of cable, which happens to be attached to a generator.
...
But... we can tap the energy of the expansion of the universe by allowing the spool to feed cable (while generating electricity) as the universe expands.

If I understand what you're saying (and I might not), you run into a few problems:

* The cable would have to be infinitely long. Once we know how to make an infinite mass, infinite energy is a snap, but until then...If the cable is not infinitely long, eventually reach it's length and that's that.

* (The more serious one) Assuming Big Bang theory, yadda yadda, the reason the universe expands is because of kinetic energy -- mass moving away from the "big bang". Assuming enough kinetic energy, gravity will never catch up -- this is true. However, if you're attaching a cable to an object and you expect the object to move the cable, the cable will be taking it's energy from the object, which means eventually the object would stop moving. Unless, of course, the cable is frictionless, but given a frictionless material, you can get perpetual motion much easier.

Re:Potential energy source?

[gilroy]

Blockquoth the poster:

Assuming Big Bang theory, yadda yadda, the reason the universe expands is because of kinetic energy -- mass moving away from the "big bang".

Actually, the Universe expands because, well, the Universe expands... it's in the nature of the spacetime metric, as one of the solutions to Einstein's equations. It doesn't (necessarily) have anything to do with kinetic energy... it's not that planets, stars, etc., are flying into empty space. It's that space itself is growing larger with time.

Re:Potential energy source?

[gilroy]

Blockquoth the poster:

I realize that space itself is also expanding, but that is a *result* of matter expanding, not the *cause* of matter expanding.

I'm sorry to repeat myself, but you are in error here. Even in an empty Universe, the Einstein equations lead to a spacetime metric that is either expanding or contracting. (I believe this solution is called a deSitter Universe.) It doesn't take matter at all, so it can't depend on the kinetic energy of matter.

To imply that it is "inherent in the space-time metric" means that there is some force causing expansion.

No, actually, it doesn't mean that at all. It means exactly what it says: the metric of spacetime -- the set of notional "metersticks" by which distance is defined -- is simply expanding as a function of time. It's in many ways the exact opposite of a force: there's no agent acting, no particle mediating the expansion, no interaction causing it. It just happens, because the structure of spacetime is such that it expands.

People intiuitively want a stable Universe, so they try to imagine things that "cause" the expansion. I believe it's very analogous to the Newtonian breakthrough in dynamics: For a long while everyone thought that the "natural" state of motion was to be at rest; therefore physical theories "had" to explain constant-velocity motion. But Newton saw that constant-velocity motion -- of which rest is just a particular case -- is the natural thing, and it is accelerations that must be explained. Likewise, people think the Universe "should" be stable and therefore think one must explain the expansion. But the Einstein equations show that the expansion is natural and therefore need not be explained further.

Re:Potential energy source?

[gilroy]

Blockquoth the poster:

Even a newtonian particle at constant velocity (to use your example) needs to somehow obtain that velocity.

Um, no. Constant velocity does not to be explained in Newtonian physics. It is just every bit as "natural" as being at rest. You might have an intuition or a bias that everything "should" have begun at rest and therefore the current state of non-rest must be explained. But that isn't implicit in Newtonian physics. The advance made by Newton was exactly the realization that changes in velocity required agents but that constant velocity does not.

I mentioned recent supernova observations and the idea that there *is* a force causing *acceleration* of expansion.

What is implied by the recent supernova observations -- and we will leave aside the argument over whether Type I supernovae are really standard candles that can be used for this sort of thing -- is that the rate of expansion of the Universe is accelerating. So much we agree upon, although we should both be cautious that these results are still preliminary (and in fact seem recently to have been scaled back some).

One possible explanation for this acceleration -- and the only one that I've seen attract serious attention from cosmologists, though they are far from unaminous on this -- is the presence of a cosmological constant in Einstein's equations. A cosmological constant acts like a pressure density defined everywhere in space and keeps the metric expanding ever faster. But it doesn't exert a "force" in any standard usage of the word. We don't need a repulsive force to accelerate the expansion, because space itself is exapnding and carrying the matter along with it.

I will admit to misusing the name "deSitter Universe", which is apparently not the construct of which I was thinking. I guess it's time to dust off ole MTW and try again.

Re:Potential energy source?

[KarmaBlackballed]

The only known way to use gravity to generate any kind of power is the harness things as they fall. The classroom description for things that can fall is that they have "potential energy."

Hydro-electric is the only successful example I can think of. Here are the problems with trying to reduce our oil dependency by using this black hole:

1. It is 40,000 light-years away. 40,000 LIGHT YEARS AWAY. Me thinks even a fraction of 1 light year is, uhhh, too far.

2. What, you need another problem? Read #1.

If you need another reason, think about this one: A light year is the distance LIGHT travels in one year. Electricity through a wire travels SLOWER than that. So, okay somehow you rigg up a generator close enough to the black hole to greate electricity. It will run down your super long wire to your PC where you are browsing Slashdot in about 40,000 years.

Why use a black hole?!....

[Dutchmaan]

.... when the Sun delivers to your door!

Re:Potential energy source?

[Violet Null]

Here's an interesting idea. It seems to me that black holes would provide a near infinite source of green (haha) power. Considering the fact that their gravitational power only increases, it is obvious that they constitute a never-ending supply of kinetic power

Problem: You can't really harness potential energy (it's potential, see?) Sure, as the black hole gets bigger, you can rest well in the knowledge that, where you to plunge towards it, you'd gain a lot more kinetic energy, but until you actually start falling towards it, you're getting squat.

what i learned from star trek

[ubugly2]

we can slingshot around the sun to a point when the black hole was just forming,then go to warp 9.9997 to get there,then create a dyson sphere around the forming black hole and then we can...we can{insert treknobabble here}.

Re:That's nice

[rebug]

they were kinda asking for that, but the other black hole is cooler. I wouldn't want to sit and throw things into mr. goatse man's black hole, and I don't think Hawking is doing much research in that particular area.

Re:That's nice

[rebug]

Hawking radiation might smell. Here's how we find out.

• build a very large catapult
• fire yourself towards this black hole. try to achieve a velocity somewhere around 1.46e+07c. we can't wait all day for your answer, you know
• as you approach the singularity, note any aromas. take notes. hurl the notes back toward earth at near infiinite velocity so they don't just get sucked in

we'll be waiting

Re:Imponderable physics question

[rebug]

What i want to know is how the hell your theoretical planet would end up living near enough to a black hole to orbit it. Plantets aren't just hanging around looking for something to orbit around, you know.

It's a scale issue. Planets don't orbit around black holes, galaxies do.

An even bigger question is...

[JetJaguar]

Assuming there were planets orbiting around the pre-blackhole star would they survive the super-nova explosion that also creates the black hole? I suspect that most planets would very nearly be ablated away or vaporized or both...

Re:Imponderable physics question

[Anonymous Coward]

The event horizon of a 14 solar mass black hole would be about 84 kilometers in diameter. A planet could certainly orbit a black hole, and the orbit would be no different than that about a non-black hole of the same mass. (Though to be picky, neutron stars can't be as massive as 14 solar masses.)

Re:Pictures?

[xanadu-xtroot.com]

I just ran across this [nasa.gov] that would certainly explain a couple things:


The Question We are deeply indebted to you if you can help us in obtaining two representative images about: 1)the real image (picture) of a "black hole" (photographed) 2)the most distant part of the Universe ever photographed.

The Answer 1) There are no "real" pictures of a black hole. This is because black holes themselves do not emit of reflect any light (that's why they are called black holes), and they are too small and too far away to be imaged. There are images of binary star systems consisting of one normal star and one black hole, and of the central regions of Galaxies that are believed to contain black holes. There are some examples of the latter, taken with the Hubble Space Telescope, at: http://imagine.gsfc.nasa.gov/docs/ask_astro/answer s/970318d.html [stsci.edu]

But these pictures don't actually show a black hole, you need to study the motion of stars to infer that there must be a black hole.

2) Again, you may want to look at some Hubble pictures (with explanations): http://imagine.gsfc.nasa.gov/docs/ask_astro/answer s/970318d.html [stsci.edu]

These are some of the most distant galaxies ever photographed; although some quasars are believed to be more distant, they make boring photographs (they just look like a point of light).

Best wishes,

Koji Mukai


(no, this isn't my work, I just found it on a Google Search [google.com])

Re:Microsoft

[rjamestaylor]

At least they're offering a fix...