as per the request of one Mr. AB, i would like to use the space afforded by my most recent blog post to discuss super lasers, specifically ones under the auspices of mad-scientists such as the ones in this article sent by mr. AB (super laser article). naturally, these scientists have a secret lab under the san francisco harbor. it only makes sense this would happen in california… im guessing these laser scientists will soon kidnap governor schwarzenegger who will require my skills to save the himself and the world. then we will fight alien hunters together in the jungle.
the basic workings of modern lasers are relatively simple, but still kind of a pain to understand unless you like physics. the basic idea is that there is a tube with some source of light and mirrors on both sides. this light shines on a bit of special material and excites electrons. think of it as a room full of 8 year olds and you give some of them candy… now they are running around like crazy. unlike the kids, this excited material gives off its energy very fast in the form of light, which is coherent with the initial light (in “harmony” – the coherence and wavelength of the light has to do with quantum physics of the material and can get pretty nasty. basically the initial light and created light make each other stronger).
anyways, this wavelength of light is roughly akin to the amount of energy given off by the kids with candy while they are in their hyper state. now imagine all these kids running around and bouncing off the walls. every time the hyper kids run into a calm kid, they both end up hyper and running off the walls. will the insanity ever end? yes, now imagine there is a little open door on one end. every now and then one of these kids is gonna randomly bounce right out that door. in a laser, the excited light is bounced back and forth off the mirrors as the excited light builds up, but the mirror allows a small amount of light to pass through each time – this is the emitted laser. the importance of a laser is that it allows a lot of energy to be built up and focused on to a very tiny spot, generating heat or bright light and other nonesuch.
if you have had enough physics bull jive, skip to the next paragraph. in this article, the scientists have further focused the laser light from 192 lasers on to a single point. the goal is to create nuclear fusion, which is used in hydrogen bombs where its only purpose is to destroy some junk but is too hard to control for any practical purposes like nuclear energy. the difference between this (nuclear fusion) and existing nuclear technology (nuclear fission) has to do with some of the basics of nuclear and quantum physics. in fission, a really large molecule like uranium is hit with a neutron (a neutral subatomic particle like protons and electrons with the same mass of a proton and are more abundant in larger atoms). this creates an unstable atom which splits apart into multiple atoms and usually an alpha (electron) or beta (two neutrons and two protons, or a helium atom without electrons) particle , giving off all the energy that was previously binding the atom together as heat. this is why atomic bombs are so devastating. after the reaction, the neutrons are stuck in smaller atoms (which again, usually have less neutrons per atom) and the neutrons are thus given off as radiation until the radioactive waste reaches a more comfortable state. the emission of these particles can create a “sustaining” reaction by crashing into other atoms and causing them to split. sustainment is controlled in a nuclear reactor by carbon rods that absorb excess atoms, while in bombs the reaction is allowed to go on uncontrolled. fusion is basically the opposite reaction – two atoms are smashed together to give off energy. this is usually hard to do because the most dense part of an atom is the nucleus, which has a bunch of positive charges. think about bringing the north poles from two really strong magnets together. nuclear forces get enormous on very small scales, so very controlled and very strong lasers must be made to bring atoms together. in enormously dense and hot objects like the sun, the gravitational force can be strong enough to compact cells together and has enough energy to make the fusion occur, which allows for the release of lots of energy. normal chemical reactions involve the exchange of electrons while fusion involves the exchange of protons (which have ~1000 times more mass and thus more energy potential). so while it may take a huge amount of focused energy from lasers to make fusion possible, it also will give off huge amounts of energy. this was the importance of the famous E=mc^2 equation – c is the speed of light (enormous) and m is the mass of a material, so as Einstein correctly postulated, a lot of energy can be released by the seperation of nuclear components. think of nuclear fusion like an investment of a few thousand $$s to a prince in africa who will then use the money to establish a bank account and deposit millions of inheritance dollars of inheritance into your coffers. the initial energy investment may be large, the payoff is well worth it!
as an aside, in general i support nuclear energy; for the last 15-20 years the technology has been tremendously safe and if you think about it the coal and gas fuel we have been using for the past century has devestated our earth as well as our own health. the biggest problem is storage of radioactive waste and there doesnt seem to be a good way to do that. and for what its worth i am in favor of reducing nuclear weapons and preventing other countries from going nuclear but thats just my 2 cents.