The dream of interstellar space travel has been around for decades. One could argue that in the case of a brilliant few, this dream has existed for centuries. In regard to this fanciful topic, and whichever school of thought is favored, one common belief serves as a constant. The energy requirements to achieve such an ambitious goal would not only be enormous, but the complete annihilation of matter itself would also be a prerequisite.
In simplest terms, matter is defined as anything that takes up space. Moreover, matter can exist in a solid, liquid, or gaseous form. Matter contains atoms, which are further broken down into protons, electrons, and neutrons. These components release positive energy. Antimatter, on the other hand, can be thought of as the polar opposite of matter.
This concept was first discovered in the late part of the 1920s by Cambridge physicist Paul Dirac. In order to explain Albert Einstein’s General Theory of Relativity, Dirac’s equations showed that electrons must also have an opposing particle equal in mass but producing negative energy. These newly-predicted particles were called positrons. A few short years later, in 1932, the existence of these negatively-charged particles was confirmed when Carl Anderson of the California Institute of Technology discovered them in cosmic ray-induced experiments. Since that time, the existence of antimatter has been verified repeatedly.
However, despite this important revelation some 80 years ago, a mystery of sorts remains. It is as follows: when a particle of matter and its antimatter counterpart collide with one another, a tremendous amount of energy is produced because they effectively annihilate each other. The amount of energy produced during such an annihilation is believed to make the force of a hydrogen bomb seem like the ruffling of a feather. Moments after the Big Bang that created the universe took place, only energy existed. As everything contained within the universe eventually cooled off from that big explosion and expanded by scattering to distances of billions of light-years away from the point of creation as it were, matter and antimatter would have been produced in equal amounts. Yet today, antimatter is a rare commodity, and physicists don’t really know why this is the case. The most popular theory is that there must have been more matter than antimatter to begin with, and moreover, a lot more.
Interestingly, in 1977, scientists discovered what they believe could be a deposit of antimatter at the center of the galaxy. If this is indeed the case, it would solve the problem of humans being forced to resort to manufacturing antimatter in a collider, and thus interstellar travel could become a reality. However, one must also keep in mind that the center of the galaxy isn’t exactly a hop and a skip away, either!
A collider can be thought of as an atom smasher. This device consists of a large tunnel with super magnets inside. In turn, the magnets cycle around and propel ordinary atoms to speeds approaching that of light. When the atoms collide with a target, particles are created. Some of these particles will turn out to be antimatter. However, even these giant supercolliders only produce one or two trillionths of a gram of antimatter per year. The energy would light a typical 100-watt light bulb for roughly three seconds, so it’s safe to say that a bit more antimatter would have to be produced to propel a spacecraft at near-light speeds. In fact, it would require many tons.
Thus, while the existence of antimatter is indisputable, the ability to produce enough of it to provide any palatable amount of energy is severely limited at the present time. Don’t expect NASA to come out with a spacecraft capable of warp drive anytime soon.
