Posted on 08/11/2011 2:05:14 PM PDT by LibWhacker
Intense pressure can force neutrons into cubes rather than spheres, say physicists
Inside atomic nuclei, protons and neutrons fill space with a packing density of 0.74, meaning that only 26 percent of the volume of the nucleus in is empty.
That's pretty efficient packing. Neutrons achieve a similar density inside neutron stars, where the force holding neutrons together is the only thing that prevents gravity from crushing the star into a black hole.
Today, Felipe Llanes-Estrada at the Technical University of Munich in Germany and Gaspar Moreno Navarro at Complutense University in Madrid, Spain, say neutrons can do even better.
These guys have calculated that under intense pressure, neutrons can switch from a spherical symmetry to a cubic one. And when that happens, neutrons pack like cubes into crystals with a packing density that approaches 100%.
Anyone wondering where such a form of matter might exist would naturally think if the centre of neutron stars. But there's a problem.
On the one hand, most neutron stars have a mass about 1.4 times that of the Sun, which is too small to generate the required pressures for cubic neutrons. On the other, stars much bigger than two solar masses collapse to form black holes.
That doesn't leave much of a mass range in which cubic neutrons can form.
As luck would have it, however, last year astronomers discovered in the constellation of Scorpius the most massive neutron star ever seen. This object, called PSR J1614-2230, has a mass 1.97 times that of the Sun.
That's about as large as theory allows (in fact its mere existence rules out various theories about the behaviour of mass at high densities). But PSR J1614-2230 is massive enough to allow the existence of cubic neutrons.
Astrophysicists will be rubbing their hands at the prospect. The change from spherical to cubic neutrons should have a big influence on the behaviour a neutron star. It would change the star's density, it's stiffness and its rate of rotation, among other things.
So astronomers will be getting their lens cloths out and polishing furiously in the hope of observing this entirely new form of matter in the distant reaches of the galaxy.
Ping to the Badger
bflr
Using this technology, airlines can get more people on a 737.
“airlines can get more people on a 737.”
Didja ever see those melons that the Japanese grow in boxes? Stackable!
Three words: square beer bottles.
I knew that! Took them this long to figure it out? maroons
It's a strange world we live in. And it's an only too fitting irony that the more deeply we delve into the ultimate nature of reality, the more unreal it becomes.
I know I could look this up but what is the distribution of stars with regard to solar mass? i.e. median star is x solar mass, one standard deviation is y solar mass etc.
I contend that because the bosons constituting neutrons are asymmetrical and so the neutrons are squeezed into little rectangles instead of cubes.
I’d have to look it up, too (and will because it never hurts to review!). But I do know most stars are dwarf stars and that the Sun is in approximately the 75th percentile when it comes to mass.
Thanks for posting. IMHO, neutron stars are some of the most fascinating objects in the universe.
You mean our sun's mass is in the 75th percentile??? And all we need is for something of the same mass to come crashing into it, and we're in a black hole???
You mean our sun's mass is in the 75th percentile??? And all we need is for something of the same mass to come crashing into it, and we're in a black hole???
But yes, you only need twice the mass of our sun to tip the scales into oblivion. The chances of something else of similar mass colliding with Sol, though, are about the equivalent of two gnats hitting each other while flying through the grand canyon.
Space is vast, especially in the outer rim of the Milky Way where we reside, to where the chances of such a thing happening are virtually nonexistent.
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