Thread: Anti matter

Can any one explain me about "anti matter". Everything including what is it and how it is formed. :P

Originally Posted by anandsatya

Can any one explain me about "anti matter". Everything including what is it and how it is formed. :P

Anti-matter is the exact same as "normal" matter except it has an oppisite charge. So the anti-matter partner of the electron (the positron) has a positive charge instead of a negative charge.

When anti-matter and matter come into contact they annihalate each other.

In the first billionths of a second after the formation of the universe, anti-matter and matter were almost equal in abundance. However there was slightly more "normal" matter then anti-matter and now there is hardly any anti-matter left.

Anti-matter is synthesized in high-energy particle collisions in particle accelerators.

Antimatter is often described as normal matter traveling backwards in time. What this means is simply that whatever normal matter does, antimatter does in a backwards manner so that if you take a motion picture of normal matter and run it backwards, it looks like antimatter.

One result is that the annihilation of matter and antimatter also looks a bit like normal matter turning around and traveling backwards in time in a different direction after emitting the energy of a photon.

In string theory all the particles can be described as the vibrational modes of strings in a ten dimensional space times so the vibrational mode of a particular antiparticle would look like the vibrational mode produced by playing a film of the vibrational mode of the corresponding particle, backwards.

Like cs-comm said, pairs of particles and their antiparticles are often produced in the high energy collisions made in particle accelerators. Another place where a particular antiparticle is commonly produced is in nuclear fusion. When four hydrogen are combined to produced helium two protons must be converted to neutrons. The positive charge of the protons are carried away by positrons (also called beta particles) which are the antiparticle of the electron. These positrons usually soon collide with an electron and annihilate to produce a high energy photon.

Please excuse my naivety but I was under the impression that you could not destroy matter, only change its form

that is true and in a matter antimatter reaction the combined mass is converted to pure energy.

Well thank goodness there is not much anti matter left, and I hope it’s a long, long distance from here, although in curved space it may be just next door!

How do we know if distant galaxies are not entirely composed of anti-matter???? Has someone figured that out? I have seen articles on the missing anti-matter, am I to believe it has simply vanished over time or that the universe is only conducive to posi-matter?

Originally Posted by zinjanthropos

How do we know if distant galaxies are not entirely composed of anti-matter???? Has someone figured that out? I have seen articles on the missing anti-matter, am I to believe it has simply vanished over time or that the universe is only conducive to posi-matter?

Well we do see a lot of collisions between galaxies and we have never seen anything like what a collision between a matter galaxy and anti-matter galaxy would look like. In fact we haven't seen anything like a collision between any massive bodies made of matter and antimatter. The incredible release of energy from such an event would be visible accross the whole known universe. Besides we have a theory in Cosmology that explains why the universe is not equal parts matter and anti-matter, in which all the antimatter annihilated with an equal part of antimatter early in the history of the universe. Not that this theory proves anything.

wouldn't the fact that the universe is made up of matter have to do with how antimatter is made. the changing set of conditions in the early universe could have prevented the creation of more antimatter.