MadSci Network: Physics |
Hi Mattias, The short answer is "nothing happens to the gravitational energy when antimatter and matter particles annihilate". I imagine you'd like a longer answer, though, so here's my attempt to explain how that works: Looking at gravity the way Newton did, every massive object attracts every other massive object, and the amount of the attractive force (called "gravity"), is proportional to the masses of the two objects. Early in the 20th century, Einstein suggested that this Newtonian theory of gravity is only an approximation, and that: 1) Mass is a form of energy. The conversion factor to figure out how many grams of mass is equal to how many ergs of energy is the speed of light squared, leading to the famous equation E = mc^2. Since the speed of light is so large, a very small amount of mass is equivalent to a really large amount of energy. 2) Gravity can be thought of as a distortion of space-time, in which the amount of the distortion is proportional to the amount of energy. Since mass is a form of energy, and it takes a lot of energy to equal a small amount of mass, you can usually ignore everything but the mass, and the amount of gravity you calculate will come out essentially correct. Thus Newton' theory still works in most situations. (Einstein also figured out a bunch of other really interesting things, most of which were laid out in two theories, called "Special Relativity" and "General Relativity". If you search the Mad Scientist archives at http://www.madsci.org/MS_search.html, you can find lots of questions and answers about Einstein's theories.) When a a particle and its antiparticle annihilate, the mass gets converted into (a different form of) energy, but the gravity stays the same, because it depends on the total energy, not just the part of the energy which we call "mass". Of course, the mass-energy is generally converted into electromagnetic radiation. (Whether visible light, or gamma rays, or X-rays, it's still electromagnetic radiation.) Since this electromagnetic radiation travels at the speed of light, the energy quickly moves away from where it started, and the gravitational forces all change accordingly. -Steve Levin ______________________________________________________ DISCLAIMER: Just because I work for JPL/NASA/Caltech doesn't mean anything I say is in any way official. This is just me talking, not NASA, JPL, or Caltech.
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