Path: ccsf.homeunix.org!ccsf.homeunix.org!news1.wakwak.com!nf1.xephion.ne.jp!onion.ish.org!onodera-news!newsfeed.media.kyoto-u.ac.jp!headwall.stanford.edu!newsfeed.stanford.edu!postnews1.google.com!not-for-mail From: tiago_simoes2@hotmail.com (tiago_simoes) Newsgroups: japan.anime.evangelion Subject: Re: N2's Date: 19 Jun 2003 09:44:58 -0700 Organization: http://groups.google.com/ Lines: 55 Message-ID: <17bad758.0306190844.c5ca18a@posting.google.com> References: <17bad758.0306151601.623f1aad@posting.google.com> NNTP-Posting-Host: 194.65.14.69 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Trace: posting.google.com 1056041099 29787 127.0.0.1 (19 Jun 2003 16:44:59 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: 19 Jun 2003 16:44:59 GMT Xref: ccsf.homeunix.org japan.anime.evangelion:5821 > Couldn't you also use a high-power laser to vaporize the air in front of the > particle beam? That might explain the fact you can see the beams from both > the rifle and the Angel. > > Vaughn L.Porter > Not that you'd see the laser anyway... I don't think it's possible to vaporize a gas... It's already vaporized, you know... :) A laser cuts things by heating them so much they evaporate. That's what happens with metal, skin and whatever you put in front of it. But if you heat up a bunch of air, the best it can do is expand a bit. There's no way to make it disappear, because it keeps coming back. It's kind of hard to explain the important points without giving a lecture on Physics, so here goes: Light, lasers, X-rays, gamma rays, radio waves, microwaves - they're all carried about by photons. Photons are closed packets of electromagnetic waves. Each photon carries a certain amount of energy. A laser has a very large number of photons concentrated in a very small area, but the energy of each individual photon is small, most times not even enough to ionize anything. That's why it's not too dangerous to be close to a laser. The only thing it can do is heat up stuff. Why can you see through air and not through a brick wall? Because air, unlike most solid objects, is almost 100% transparent to photons. So the laser just goes through, almost not heating up the air at all. Particle beams are altogether different. Each one of the particles has a very high energy (because the particles have mass, and E=mc^2). So, when one of the particles hits a molecule, it can tear it completely apart and produce a shower of smaller particles in all directions. The air is transparent to photons, but not to all particles. For example, you don't get hurt by electricity unless you actually touch a conductor, wich means air is not transparent for electrons.* Besides, for reasons somewhat obscure at this point (cross-sections and things like that), it's much more likely for a massive particle to hit an atom than for a photon, so a particle beam hits molecules much more easily than a light beam. Resuming: you can't use a laser to get the air out of the way, and you can't use a particle beam unless you get the air out of the way. Hope you didn't fall asleep... Tiago Simões *Lightnings occur when the amount of electricity is enough to create a stable electric current through the air, but this only happens because "air" is not the only thing in the atmosphere. There's water vapor, conductive dust particles, etc.