Antimatter

This is also a fascinating subject, and one that has been used in science fiction for some time. But, how realistic is antimatter and can it be used for power generation?

First of all, what exactly is antimatter? The best way to understand antimatter is with the science of quantum physics, which says that for every particle there is a corresponding antimatter particle. For example, the proton's evil twin is the antiproton. The electron's twin is the positron. Basically, all baryonic particles have a corresponding antiparticle.
What's the difference between a normal particle and an antiparticle? Usually, the difference is in the particle's electrical charge. For example, a proton has a positive charge, whereas an antiproton has a negative charge. An electron has a negative charge, of course, and the positron is an electron with a positive charge.

Most people know that when matter and antimatter meet they are mutually annihilated with the release of tremendous amount of energy in the form of light, mostly gamma rays.

Physicists have had a terrible time trying to study antimatter because it's very difficult to create a sizable amount and have it stay around long enough to do experiments. The science of antimatter containment is important in the hopes of using this very important source of energy for interplanetary and interstellar voyages. Antimatter power is at least three orders of magnitude greater than nuclear energy, so it would be very efficient.

Antimatter actually exists for brief periods in nature. Radioactive decay of some isotopes creates antimatter particles that are instantly annihilated to produce quanta of gamma rays. Cosmic rays also create antimatter particles. Antimatter particles are produced in very high temperatures, which exist around black holes.

How is antimatter created artificially? The usual method is by colliding protons in a cyclotron, better known as a collider. Antimatter is created at very high temperatures greater than 10 trillion degrees.  Hot protons are shot into an iridium rod, which creates both matter and antimatter. Antiprotons from this process are isolated in a vacuum using magnets. The problem is that they don't last very long, only fractions of a second.

Another more efficient method of producing antiprotons is to blast electrons into millimeter-thick gold using an ultra-intense laser. The Lawrence Livermore National Laboratory developed this method.

The first order of business was to determine if antimatter is precisely the same as matter other than for electrical charge. The ALPHA team at CERN did this experiment using a device (Antiproton decelerator) that is able to decelerate antimatter and cool it sufficiently to avoid an explosion. Essentially, it's a clever method of taming the antimatter beast by cooling it in an ingenious trap. This idea was used to trap anti-hydrogen atoms, but only for a limited time (1000 seconds). The next step was to pass laser light through the anti-hydrogen and measure the resulting spectrum. What they found was that anti-hydrogen behaves exactly like normal hydrogen. This was predicted by Einstein but never verified until now.

Larger antimatter atoms are very difficult to produce. It appears that the most logical source of antimatter will more than likely be antiprotons. They could possibly be stored in a magnetic cold trap for extended periods of time. This technology would allow antiprotons to be used as fuel for spacecraft.

I would think that producing antimatter in sufficient quantities would be a huge engineering problem. Cyclotrons are large and very heavy. Installing one on a spacecraft would be a tricky proposition. Maybe the Lawrence Livermore Lab idea would weigh less. Even if the creation method could be worked out, storing the antimatter would still be a big problem. Magnets are heavy and electromagnets require gobs of energy. These technical problems need to be solved before antimatter propulsion will become a reality.

Thanks for reading.