Added 1 new A* page:Today I happened to stumble across this Yahoo! news blog post about how a Connecticut-based company, Laser Power Systems, is working on a zero-emissions car powered by thorium, a naturally occuring soft metal, named after the Norse god Thor by Swedish chemist Jöns Jakob Berzelius, who discovered the element in 1815. Thorium is mildly radioactive--the alpha radiation is emits cannot penetrate human skin--and has some useful properties that have led it to being used in things such as gas mantles--the little white baggy things that glow in lanterns--and as "an antireflection material in multilayered optical coatings." On the other hand, it is potentially dangerous in powder (spontaneous combustion in air) or aerosol (increased risk of cancer if inhaled due to alpha radiation damage to internal organs) forms.
Another property of thorium, apparently, is that it produces "heat surges" when heated by a laser, and Laser Power Systems says that eight grams of thorium, laser-heated correctly, with the resulting heat-surges being used to generate steam to power a turbine, could power a car for its entire lifetime.
There are, of course, some technical issues with this scheme, including getting dedicated thorium mining underway. Thorium is three times more abundant than uranium, being found in most rocks and soils, and a number of countries have been considering how to use it as a fuel source in nuclear reactors; there are a number of advantages it could have in that capacity over uranium, aside from its greater abundance; for instance, it's harder to get weapon-grade material from it to turn into nasty nuclear weapons, its radioactive waste decays much more quickly, it doesn't require an expensive enrichment process, and it doesn't sustain a nuclear chain reaction by itself, so a meltdown would be much less likely.
India, which "has about 25% of the world's thorium reserves," has already used thorium in one nuclear reactor, and is preparing a line of thorium-based reactors, the prototype of which is scheduled to go online this year.
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And speaking of exotic fuels, this ScienceNOW article says that scientists working with the joint Italian, German, Russian, and Swedish PAMELA satellite (that's "Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics") have announced that they've confirmed the existence of antimatter in the Van Allen radiation belt encircling the Earth; since 1978 or so (when researchers came up with the theoretical CRAND ("Cosmic Ray Albedo Neutron Decay") process to describe how this could happen, I think) antimatter has been theorized to form there when high-energy cosmic rays smash into the upper atmosphere; eventually this interaction yields antiprotons, which are then trapped there by the Earth's magnetic field.
PAMELA spent 850 days sampling for antimatter in the belt regions, and succeeded in collecting 28 antiprotons; that doesn't sound like much, but it's apparently 1000 times the estimated galactic norm--"thereby constituting the most abundant antiproton source near the Earth" concluded the scientists in their research paper.
That ScienceNOW article goes on some flights of fancy about how this antimatter source could be harnessed for space flight--antimatter of course being in theory the ideal fuel, with its 100% efficient matter-to-energy conversion rate--but needless to say the amount of antimatter estimated to be in the belt, even if it could be collected and stored somehow for ship fuel, wouldn't amount to all that much; then again, it's still very difficult to manufacture antimatter on Earth, so even that tiny amount might be useful...if someone some day works out a feasible way to store the stuff for more than a split second.
(Thanks to Calamities of Nature, 'cause that webcomic's recent blog entry is where I found the ScienceNOW link.)
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