Tag Archives: black-holes

Black Hole Sun, redux: are supercivs sucking at the event horizon?

Via Sentient Developments, here’s some brainfood for them as likes their high-concept cosmological hard SF. Y’know how SETI has yet to locate any alien civilisational traces by looking for large-scale exploitation of stellar energy sources? Well, perhaps they’re looking in the wrong cupboard; a new paper from Clement Vidal of the Evolution, Complexity and Cognition group at the Vrije Universiteit Brussel posits that black holes are the ideal energy source for an ultra-advanced civilisation, and that our own universe might actually be “a science fair project of an entity from an exo-universe”:

Energy-hungry galactic empires might skip tapping stellar energy and simply go to extracting energy from black holes. These collapsed islands of space-time are the universe’s ultimate Energizer Bunnies. They are far more efficient at converting mass to energy than are the fusion engines of stars.

But more than that, says Vidal, is the ability to control the microcosm as well. Today we can manipulate individual atoms via nanotechnology. But advanced alien physicists would tinker with elementary particles and the very structure of space-time itself.

Having mastered control over space-time, a super-civilization might want to fabricate their own black holes for a variety of tasks: waste disposal, starship propulsion, hyper-computing, maybe even time travel.

On the macro-scale, super-civilizations might re-engineer stars using black holes. The quest for immortality beyond a star’s lifetime would be a big motivation.

Suppose extraterrestrials manufacture a black hole to accrete material from a burned-out star, a white dwarf. This would provide abundant energy beyond the star’s fusion-burning stage.

It may be impossible to define sensawunda, but I can sure as hell point it out when I see it. *points*

Does a massive miscalculation mean the LHC really could destroy the world?

The LHC will eat your home planet. Maybe.Remember all that beef about the possibility of the LHC producing uncontrollable black holes that could DESTROY TEH WORLD OMG? Well, it’s still highly unlikely, but it turns out that the way these things are calculated aren’t as reassuring as we might perhaps want them to be:

The problem is compounded when the chances of a planet-destroying event are deemed to be tiny. In that case, these chances are dwarfed by the chances of an error in the argument. “If the probability estimate given by an argument is dwarfed by the chance that the argument itself is flawed, then the estimate is suspect,” say Ord and co.

Nobody at CERN has put a figure on the chances of the LHC destroying the planet. One study simply said: “there is no risk of any significance whatsoever from such black holes”.

Which means we are left with the possibility that their argument is wrong which Ord reckons conservatively to be about 10^-4, meaning that out of a sample of 10,000 independent arguments of similar apparent merit, one would have a serious error.

In layman’s terms, the above doesn’t mean that the LHC is dangerous, it just means that the assurances of its safety are predicated on flaky calculations. The difference between the two is left as an exercise for the reader. 😉 [via SlashDot; image by muriel_vd]

It’s the way you walk…

walkingResearchers from Scotland and Belgium have identified a link between a woman’s stride and orgasmic ability:

The results showed that the appropriately trained sexologists were able to correctly infer vaginal orgasm through watching the way the women walked over 80 percent of the time. Further analysis revealed that the sum of stride length and vertebral rotation was greater for the vaginally orgasmic women. “This could reflect the free, unblocked energetic flow from the legs through the pelvis to the spine,” the authors note.

Another advance in the onward march of science…

In slightly more directly sfnal news scientists have discovered an upper limit to the mass of black holes:

…these gigantic black holes, which accumulate mass by sucking in matter from neighboring gas, dust and stars, seem unable to grow beyond this limit regardless of where – and when – they appear in the universe.

This may affect some of the long term predictions of the future of the universe, as expounded in Stephen Baxter‘s Deep Future, which is well worth a read.

[both stories from Physorg][image from pizzodisevo on flickr]

The monsters at the bottom of black holes!

BlackHole No, it’s not the title of some best-forgotten B-movie, but some high-brow astrophysics that – in all honesty – I can’t say I fully understand. But it’s something to do with quantum physics, entropy and super-massive black holes:

“Although Hawking radiation implies that black holes contain all this disorder, scientists have been puzzled as to where it all comes from. The collapsing stars that turn into black holes do not start out with nearly enough. How does the matter become so scrambled?

Frampton’s team argues that the extra entropy is generated by the random nature of quantum physics. This should sometimes allow a collapsing ball of matter to spontaneously transform into something called a “monster” – an arrangement of matter that has maximum disorder, with particles travelling at high speed in random directions.”

These “monsters” could help explain our way to a quantum theory of gravity, apparently. It’s times like this I wish I’d stuck with science instead of engineering. [Image courtesy NASA]

[tags]space, black holes, monsters, physics[/tags]

Rogue black holes wander the galaxy, seeking whom they may devour

blackhole There’s a science fiction tale or two to be dug out of this little science item, I’m thinking:

If the latest simulation of what happens when black holes merge is correct, there could be hundreds of rogue black holes, each weighing several thousand times the mass of the sun, roaming around the Milky Way galaxy.

The simulation in question is focused on “intermediate mass” black holes, and there isn’t really even any strong evidence that such things, weighing a few thousand solar masses, exist. (Via PhysOrg.)

Still, if they exist, and two of them of different sizes and rotating at different speeds combine, the simulation indicates resulting merged black hole gets a kick in the pants that can hurl it away in an arbitrary direction at a velocity that averages 200 kilometres per second but in some instances can be as high as 4,000 kilometres per second–enough in either case to allow the black hole to escape the globular cluster where these intermediate black holes (if they exist) are predicted to form.

The researchers are reassuring:

“These rogue black holes are extremely unlikely to do any damage to us in the lifetime of the universe,” Holley-Bockelmann stresses. “Their danger zone, the Schwarzschild radius, is really tiny, only a few hundred kilometers. There are far more dangerous things in our neighborhood!”

Of course, anything with a mass of a few thousands suns wandering close to the solar system is going to play havoc with planetary orbits…but fortunately, space is very, very big.

It’s probably nothing to worry about.

(Image: Ute Kraus, Max-Planck-Institut für Gravitationsphysik, Golm, and Theoretische Astrophysik, Universität Tübingen, www.spacetimetravel.org)

[tags]astronomy, space, black holes[/tags]