In the beginning, the one where time itself began, the theory goes that matter and antimatter were created in equal amounts. When matter and antimatter meet they annihilate each other in a perfect transformation of matter into energy which should have meant that our universe consisted of nothing else. However, for some strange reason, the universe has a small preference for matter over antimatter, to the tune of 1 parts in 10 billion. This is why our universe is the way it is, filled with billions of galaxies and planets, with the only remnant of the cataclysmic creation being the cosmic microwave background that permeates our universe with bizarre consistency. The question of why our universe has a slight preference for matter has puzzled scientists for the better part of a century although we’re honing in on an answer.
If you had the ability to see microwaves then the night sky would have a faint glow about it, one that was the same no matter which direction you looked in. This uniform background radiation is a relic of the early universe where matter and antimatter were continuously annihilating each other, leaving behind innumerable photons that now permeate every corner of the known universe. What’s rather perplexing is that we haven’t observed any primordial antimatter left over from the big bang, only the matter that makes up the observable universe. This lack of antimatter means that, for some reason or another, our universe has an asymmetry in it that has a preference for matter. Where this asymmetry lies though is still unknown but we’re slowly eliminating its hiding spots.
The Antihydrogen Laser Physics Apparatus (ALPHA) team at CERN has been conducting experiments with antimatter for some time now. They have been successfully capturing antiprotons for several years and have recently moved up to capturing antihydrogen atoms. Their approach to doing this is quite novel as traditional means of capturing antimatter usually revolve around strong magnetic fields which limit what kinds of analysis you can do on them. ALPHA’s detector can transfer the antihydrogen away from their initial capture region to another one which has a uniform electric field, allowing them to perform measurements on them. Antihydrogen is electrically neutral, much like its twin hydrogen, so the field shouldn’t deflect them. The results have shown that antihydrogen particles have a charge that’s equivalent to 0, showing that it shares the same properties as its regular matter brethren.
This might not sound like a much of a revelation however it was a potential spot for the universe’s asymmetry to pop up in. Had the charge of the antihydrogen atom been significantly different from that of hydrogen it would’ve been a clue as to the source of the universe’s preference for matter. We’ve found that not to be the case so it means that the asymmetry exists somewhere else. While this doesn’t exactly tell us where it might be it does rule out one possibility which is about as good as it gets in modern science. There’s still many more experiments to be done by the ALPHA team and I have no doubt they’ll be significant contributors to modelling just similar matter and antimatter are.
Most people have a rough idea about what plasma is, usually thanks to the plasma TV craze that hit many years ago and has since been replaced by LCDs, but few will know that plasma is actually one of the 4 fundamental states of matter right along side solid, liquid and gas. The transition between a gas and a plasma is done through a process called ionization/deionization which converts the gas into an electrically conductive cloud which can be done by either inducing a large voltage difference or by subjecting the gas to extremely high tempreatures. The following video shows the latter and is a rather cool demonstration of the transition process.
The short run time for sustaining the plasma cloud is simple, given enough time that superheated cloud of carbon atoms would start to melt the pyrex container which would free the plasma to wreck all sorts of havok on the microwave itself. I’m not sure how long it’d last though as it looks like the atomised carbon atoms need to be cluster together for it to work, hence the spool up time require to set up the initial plasma reaction. Indeed if my experiments with bananas are anything to go by (it’s relatively safe but still, I’m not going to recommend you do it) you’d instead get little flashes rather than the sustained cloud.
What really interested me was the hum that was generated as it was pretty regular and I couldn’t really figure out what would be causing it. As it turns out there’s actually a couple things that could be responsible and, interestingly enough, the frequency could change depending on the input frequency of the power source going to the microwave. That link also suggests another, similar experiment with cut in half grapes that’s supposedly a lot safer (although this site argues otherwise) and the results look very similar to my results with bananas. It seems there’s all manner of things you can use to create plasma in the microwave, something I didn’t expect.
This is one of those experiments that I reckon would be really great for class demonstrations (this is probably also the reason why I shouldn’t be allow to teach science in schools but come on, fire and explosions are awesome!).