Sunday, August 13, 2017

Faster Than Superfluid Helium...

I've often said that one the reasons I blog is because it lets me pretend I am Mike Royko.

Another reason is the opportunity I have to write, every now and again, about quark-gluon plasma. For some reason, this particular substance, existing only under the most extreme conditions in particle accelerators, is as much fun to type as it is to say, and occasionally during the blog's 9.5 years of existence something about it has crossed my path.

Today it's an article from Physics World, which reports that quark-gluon plasma has set a record as the fastest-rotating liquid yet created. The plasma is created when gold ions are fired into each other at great energies, and then the quarks that make up the ions become "deconfined," which means they break down into individual quarks instead of making up larger subatomic particles. The gluons that hold them together also break apart, and the substance that results is a state of matter called "plasma."

Since we're talking about amazingly small bits of matter, the collisions are usually at an angle, so the plasma starts out with a high rate of rotation. Scientists measure the speed by seeing what gets thrown off the glob of plasma as it spins.

The previous record holder for spin velocity was something called superfluid helium, which is a peculiar liquid-ish state of that gas reached when it is cooled to almost absolute zero. It has zero viscosity (the measure of how "thick" a liquid is -- pancake syrup has greater viscosity than water, for example), so it can spin up a vortex at 107 rotations per second. Quark-gluon plasma, by comparison, creates a vortex that spins at 1022 rotations per second. A tornado about 60 yards wide with 300-mph winds spins at about three-fourths of a revolution per second.

Cosmologists think that the universe, right after the Big Bang, was a lot like quark-gluon plasma until it cooled down enough for subatomic particles like protons and electrons to form, so they want to learn about it and see what it can tell us about that very early universe. It may even be able to explain the electoral victories of Donald Trump and Elizabeth Warren.

Or maybe not. There's only so much one can ask of a substance, no matter how cool its name is.

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