Summary -
(Aug 1, 2005) 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.
Full Story -
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Degree of
interaction among quarks in liquid
gold-gold collisions. Image credit:
RHIC Click
to enlarge |
Using high-speed
collisions between gold atoms, scientists
think they have re-created one of the most
mysterious forms of matter in the universe
-- quark-gluon plasma. This form of matter
was present during the first microsecond of
the Big Bang and may still exist at the
cores of dense, distant stars.
UC Davis physics professor Daniel Cebra is
one of 543 collaborators on the research.
His main role was building the electronic
listening devices that collect information
about the collisions, a job he compared to
"troubleshooting 120,000 stereo systems."
Now, using those detectors, "we look for
trends in what happened during the collision
to learn what the quark-gluon plasma is
like," he said.
"We have been trying to melt neutrons and
protons, the building blocks of atomic
nuclei, into their constituent quarks and
gluons," Cebra said. "We needed a lot of
heat, pressure and energy, all localized in
a small space."
The scientists produced the right conditions
with head-on collisions between the nuclei
of gold atoms. The resulting quark-gluon
plasma lasted an extremely short time --
less than 10-20 seconds, Cebra said. But the
collision left tracings that the scientists
could measure.
"Our work is like accident reconstruction,"
Cebra said. "We see fragments coming out of
a collision, and we construct that
information back to very small points."
Quark-gluon plasma was expected to behave
like a gas, but the data shows a more
liquid-like substance. The plasma is less
compressible than expected, which means that
it may be able to support the cores of very
dense stars.
"If a neutron star gets large and dense
enough, it may go through a quark phase, or
it may just collapse into a black hole,"
Cebra said. "To support a quark star, the
quark-gluon plasma would need rigidity. We
now expect there to be quark stars, but they
will be hard to study. If they exist,
they're semi-infinitely far away."
The project is led by Brookhaven National
Laboratory and Lawrence Berkeley National
Laboratory, with collaborators at 52
institutions worldwide. The work was done in
Brookhaven's Relativistic Heavy Ion Collider
(RHIC).
Original Source: UC
Davis News Release
