btc@hp-pcd.UUCP (05/18/84)
Recently I (a non-physicist) attended a talk on cosmology. One of the items mentioned was the concept of matter and anti-matter. At the end of the lecture I asked if there was such a thing as anti- energy, and received a patronizing NO. Any explanations from out there in net-land that I can understand? (not simplistic, but not filled with technical jargon). Thanks, Bob Clark hp-pcd!btc
Craig.Everhart@CMU-CS-A.ARPA (05/23/84)
What's there to know? There are two species of each kind of particle. When one of them occurs ``naturally'' (e.g. in abundance in this universe, or at least on this planet) we unambiguously call it a particle, and its conjugate an anti-particle. Other pairs are named more or less by convention. You can make atoms out of anti-particles just fine, if you have enough of them--positrons circling a nucleus made up of anti-protons and anti-neutrons. When a particle and its conjugate (the ``anti-particle'') come within range of one another, they can annihilate one another to produce energy. Conversely, if momentum is conserved, a photon of sufficient energy can produce two oppositely-conjugated particles, one of which we call a particle and the other of which we call an anti-particle. You've invented a word (``anti-energy'') by a word game. How would it behave? Presumably, you think that turning ``anti-matter'' to energy would result in ``anti-energy.'' What would its properties be? Would it annihilate regular old energy and produce some kind of matter? If there were people made of anti-matter (in some other galaxy, say) would they have anti-ideas rather than ideas? If one of them baked a cake, would their ovens be anti-hot rather than hot? Would they experience anti-gravity rather than gravity? (Actually,as I understand it, a definite no to the last question; antiparticles and particles share gravitational attraction, just as they share a concept of mass.)
csc@watmath.UUCP (Computer Sci Club) (05/25/84)
The idea is that the universe has a fixed amount of energy. This energy comes in many forms one of which is Matter (with a capital M). Matter comes in two forms matter, and anti-matter. Both are a form of energy. (a proton and an anti-proton represent the same amount of energy). Certain conservations laws state that if matter is created or destroyed then an equivalent amount of anti-matter must be created or destroyed. We do not need an anti-energy in this model. One could postulate an anti-energy, call it negative energy, from which was formed negative matter. In the same way as a proton and an anti-proton combine to give a burst of energy, a proton and a negative proton would comine to give nothing. The problem with this theory is that there one would expect the oposite to occur, that is nothing decay to form a proton and a negative proton (which would have negative kinetic energy, whatever that means). We do not observe protons and negative protons popping out of nowhere (at least we do not observe protons, we might not be able to easily detect negative protons, exept perhaps by watching protons disappear) so this model loses credibility. William Hughes Interesting idea though it would alow one to get around the first law without breaking it.