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Really Mad Science! The Postronium Gamma Ray Laser

Postronium_laser_cartoon Scientists at the University of California have proposed a design for an anti-matter fueled gamma ray laser, in what can only be taken as proof that:

a) We need a Nobel Prize in Mad Science
b) We need to award it to these guys before they detonate half the planet.

The unstable heart of their design is a material called Positronium, which couldn't sound more like a science-fiction invention if Doctor Who was explaining it to a female sidekick.  Possibly the most awesome idea ever put forward by mankind, it's an atom made of half matter and half antimatter.  Antimatter being "The stuff that explodes if it touches matter".  In fact the resulting detonation isn't called an "explosion", it's called "annihilation" - and that's by scientists, the sort of people who can describe a collapsing star as "an interesting phenomenon".  To put it into perspective: a nuclear reaction releases about 0.1 % of the energy contained in matter - an antimatter annihilation releases 100%.

An electron and it's evil anti-twin, a positron, can orbit around each other in a lovely co-operative state of affairs that lasts for a whole ten-millionth of a second before they notice each other, do the tiniest double-take in history, then annihilate in a blast of gamma-rays.  Not content with a self-destructing atom, David Cassidy and Allen Mills coaxed a couple of positronium atoms together to form a molecule in the fastest and most dangerous piece of matchmaking in history.  So now you know why Arnold Schwarzzeneger got into politics - it wasn't through any career aspirations, but because he'd been rendered obsolete by the production of a material whose sole purpose is to blow things up in a spectacular fashion.

Having found a way to produce one of the most mind-blisteringly crazy cool substances in the universe, they now want to build a laser out of it - in proof that some people could look at a cheer-leading pyramid of naked Angelina Jolies and go "Yeah, I suppose that's pretty cool, but it'd be better if they were kung fu fighting".  Even better, they have a theory for how this conflation of awesome science could be achieved.

Regular lasers operate between two energy levels, usually in something pedestrian like a special crystal - when an electron falls from the higher level to the lower, it releases a photon.  The trick is that this photon can trigger other electrons in the upper level to fall and release similar photons in a process called 'stimulated emission' leading to an avalanche of coherent light - a laser.  In the normal scheme of things there will be more electrons in the lower level than the higher, so to get a good laser going you have to produce a 'population inversion'  - more electrons in the higher level than the lower.

Cassidy and Mills have redefined the concept of awesome by proposing a laser whose two levels are "Goddamn half-antimatter positronium" and "KABOOM", with a chain of atomic annihilations producing gamma-ray photons - giving rise to a goddamn gamma ray laser a million times more powerful than anything our primitive mortal science has yet seen. Note that while scientific correspondents are encouraged not to swear, when a sentence contains the phrases "antimatter", "laser" AND "gamma rays" then the "Goddamn!"s are spontaneously generated.

Science is a wonderland of awesome, but it's genuinely hard to imagine how anyone will top this without inventing a Higgs Boson producing Moon Collider or something.  But that's what we love about it - what you can't imagine today, someone has worked out how to do tomorrow.

Posted by Luke McKinney.

Positronium Gamma Ray Laser


While I love the exposure that articles like this give to cutting edge science, there are always losses in translation of science to a wide audience and this article is no exception. I love the enthusiasm and wit of this article but there are a few scientific problems with it and as a scientist myself I'd like to highlight those.

First, positronium is not a new substance. It's been observed and/or created since the 1950s, and was predicted way back in the 1930s. Second, matter and antimatter do not 'explode' when they come into contact - they annihilate, a process whereby their mass-energy is converted purely to energy in the form of light. This is nothing like an atomic bomb, and it's nothing new. In fact, the particle accelerator at SLAC in Menlo Park, CA. has been doing matter-antimatter collisions between positrons and electrons for years. An explosion on the other hand is a much dirtier affair, and usually involves rapid, violent oxidation reactions and the release of gases and a lot of heat.

Finally, while matter and antimatter can annihilate each other, positronium is a substance that exists (albeit for a relatively short lifespan) in a bound state, a relatively stable quantum configuration that allows each particle to exist and orbit the other for a time without annihilating, much like the Earth orbits the Sun in constant free-fall without actually falling into the Sun. In fact, the ground state of positronium is not much more complicated than that of a hydrogen atom, the most abundant substance in the universe, next to dark matter and dark energy.

Again, I love this article and I can't wait to read more about these amazing discoveries but I think it's important for the general public to know that this isn't "mad science," that happened recently because scientists were bored or were seeking attention. This is cool stuff, but it stands on a foundation of solid science, with a hope for amazing applications in the future (look into the LCLS x-ray FEL laser as a proxy example).

Can these gamma lasers or Gasers used to make blasters like those shown in sci-fi films? We can get rid of guns and bullets and old fashioned things like that!

"Second, matter and antimatter do not 'explode' when they come into contact - they annihilate, a process whereby their mass-energy is converted purely to energy in the form of light."

One giant booboo with that phrase is to say annihilation is "purely to energy in the form of light". That would make it seem combining a gram of anti-lead with matter would make a pretty flash while in reality it would indeed annihilate a city. a HUGE portion of the reaction in released in the form of neutrinos so one could say light isnt even the major product of annihilation. Shame all those neutrinos are essentially harmless and worthless as well as invisible... but the point is is that annihilation is enormously destructive and saying it is a light show is just shameless.

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