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Fraser
2005-Aug-01, 04:29 PM
SUMMARY: Physicists have used the Brookhaven National Laboratory's Relativistic Heavy Ion Collider to create quark-gluon plasma; a mysterious form of matter that was probably present in the first moments after the Big Bang. The team created it by smashing the nuclei of gold atoms together at relativistic speeds. The resulting explosion of particles lasted just 10-20 seconds. Astronomers think that large neutron stars might go into a quark-gluon phase before they collapse into black holes.

View full article (http://www.universetoday.com/am/publish/rhic_detect_traces_of_mystery_matter.html)

What do you think about this story? Post your comments below.

antoniseb
2005-Aug-01, 04:51 PM
Originally posted by fraser@Aug 1 2005, 04:29 PM
The team created it by smashing the nuclei of gold atoms together at relativistic speeds.
Some of you may be wondering why they used Gold nuclei. It is probably the case that they chose Gold because it is the cheapest heavy element that you can get fairly isotopically pure samples of. Au-197 is the only stable isotope of Gold, with none of the other isotopes having lives long enough to matter, so simple chemical means can be used to make very pure gold. The same cannot be said for seemingly cheaper materials such as Mercury, Lead, or Uranium.

It is very interesting that this experiment seems to be showing a relative incompressability for the Quark-Gluon Plasma. This is a new state of matter for us to explore, and we obvioulsy have a lot to learn about it.

om@umr.edu
2005-Aug-01, 05:53 PM
This is interesting, although I question how many correct conclusions can be reached on a quark-gluon plasma that "lasted an extremely short time -- less than 10-20 seconds".

One comment seemed to support my concerns about the existence of black holes.

"The plasma is less compressible than expected, which means that it may be able to support the cores of very dense stars."

With kind regards,

Oliver
http://www.umr.edu/~om

antoniseb
2005-Aug-01, 06:51 PM
Originally posted by om@umr.edu@Aug 1 2005, 05:53 PM
One comment seemed to support my concerns about the existence of black holes.
If by black hole you mean something with a gravitational event horizon, then this is not an obstacle. If you mean a geometric point singularity, then sure, but there can still be things with all the outward properties of a black hole.

BTW, I'm sure you already know this, but for the sake of other readers that extremely short time is 10^-20 seconds. (One percent of an attosecond).

Don Alexander
2005-Aug-01, 07:23 PM
If this Quark-Gluon plasma really becomes incompressible under a certain regime, then Witten's conjecture that this is the ground state of Quantum Chromodynamics should be fulfilled. The Schwarzschild radius grows faster than the radius of the incompressible strange quark star, and at a critical mass, the star will become a black hole without being a singularity.

Duane
2005-Aug-02, 05:53 PM
Another thing to keep in mind os that the incompressibility of the plasma on Earth may be more related to the lack of pressure we can put on the plasma while it is in existance.

In the eviroment of a supernova, the occurence of this plasma in the central part of the newly created neutron star might be under enough pressure to remain as a super-dense centre for the NS.

Mild mannered
2005-Aug-03, 11:31 AM
I agree with Duane

This "incompressibility" may just be realtive

An ant standing on a tin can would say it was pretty incompressible - my foot, with 200lbs plus behind it says different.

Have we worked out the pressure exterted on the plasma relative to what it would experience in a black hole? What percentage?