Do the Bose-nova (or rather, don't) - September 30, 2008
Posted for Philip Ball
Whereas you might expect that scientists in the CERN theory group have their hands full predicting what the Large Hadron Collider is likely to brew up once it is finally up and running, it seems that some of them are too busy firefighting lunatic scare stories. It wasn’t enough to produce a fat document dismissing the concerns that the LHC will generate planet-gobbling strangelets or black holes; now they have had to demonstrate that the liquid-helium cryogenic system is safe too.
What’s wrong with a few thousand gallons of superfluid helium, you might wonder, particularly as the stuff has been used routinely in physics departments throughout the world? (Apart, that is, from its proneness to leak out in the face of the recent ‘meltdown’ of the magnets.) Well, in 2001 researchers found that by tuning the attractive interactions between metal atoms in an ultracold gaseous state called a Bose-Einstein condensation, they could induce an implosion dubbed a ‘Bose-nova’ that led to a subsequent mini-explosion as the atoms were expelled from the condensate. And helium-4 can form a Bose-Einstein condensate too – so might it undergo its own Bose-nova ?
Litigants who have lodged court cases to try to prevent the LHC from ‘endangering’ the planet have seized on this idea, and even suggested that a Bose-nova might be a kind of cold nuclear fusion. But Malcolm Fairbairn and Bob McElrath at CERN point out that helium-4 atoms lack the electronic properties needed to induce Bose-nova collapse. And even if “some fantastic physics in violation of quantum mechanics somehow enabled helium molecules to undergo a Bose-nova collapse resulting in nuclear reactions”, they say, it couldn’t sustain such a process to lead to runaway nuclear fusion.
Can everyone get on with their normal jobs now?
Image: CERN
Comments
The real “black hole danger” doesn’t involve LHC or JILA.
CERN or other high-energy labs might manage to create a Higgs boson or even a micro black hole. Such a thing would be extremely hot, and extremely hot things evaporate extremely quickly. They barely live long enough to reach a detector, let alone swallow the earth.
Cornell and Wieman earned their Nobels by creating the world’s first Bose-Einstein condensate. Their condensates are extremely cold, and can’t stand any contact with ordinary matter. If you suddenly exposed such a BEC to “empty” space (which has heat left from the big bang), the BEC would die billions of times quicker than a sheepdog trapped in a hot car.
The real danger comes from Goldilocks BEC’s. Suppose someone makes a BEC which is completely stable at room temperature and beyond (in particular, 15000 degrees, roughly the temperature of the earth’s core). What happens when the stable BEC touches ordinary matter? It won’t just bounce off like ordinary fermionic matter. It’s too big to pass through like a neutrino. If it absorbs ordinary matter, and we can’t kill it, it will kill us.
BEC research is a very hot (pun not intended) area in current physics. Demokritov et al have already produced room-temperature Bose-Einstein condensates using magnons. These aren’t Goldilocks BEC’s, because magnons aren’t stable matter in the same sense as rubidium. But Goldilocks BEC’s are coming, and we can’t stop them.
My prediction may look gloomy, but my conclusion isn’t. I can sum it up in a single word: repent.
Posted by: John Stout | August 29, 2009 04:27 AM