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The production of antimatter is a costly process, both in terms of time and money. The production of a nanogram (a billionth of a gram) of antihydrogen costs a few hundred million euros. Considering these difficulties, why is antimatter worth researching?

The main reason is its scientific interest: research on antimatter allows us to learn more about our universe. The ALPHA collaboration, for example, wants to study if matter and antimatter are exactly symmetrical. The laws of physics offer certain predictions in this respect, but experimentation could prove them wrong. It is through this process of observation, prediction and testing that science advances.

The study of antimatter is also appealing for other reasons. The annihilation of matter and antimatter is a process that generates surprising amounts of energy, very superior to what can be obtained through chemical or nuclear processes (both of fusion and fission). Only half a gram of antimatter in contact with half a gram of matter would liberate the energy of a 20 kiloton nuclear bomb, that is, the energy of a nuclear bomb like Hiroshima.

PROCESS	LIBERATED ENERGY	EQUIVALENCIES
Combustion of 1 Kg oil	4,2 x 10⁷J = 42,000.000 J	-
Nuclear fusion of 1 Kg hydrogen	2,6 x 10¹⁵J = 2.600,000.000,000.000 J	55 million Kg of oil
Annihilation of 1 Kg antihydrogen with 1 Kg hydrogen	1,8 x 10¹⁷J = 180.000,000.000,000.000 J	3.800 million Kg of oil

These processes are so energetic because, in the annihilation, all the mass of the matter and the antimatter completely transforms in energy. For the same reason, this is "clean" energy that does not leave any residues behind.

Can then antimatter be used to make a bomb? And can it be used as fuel, for instance to propel spaceships? Science fiction tells us so. In the television series Star Trek antimatter is the fuel of the Enterprise. And in Dan Brown's popular novel Angels and Demons, antimatter is used to build a bomb of enormous destructive power. In what ways are reality and fiction similar? Can antimatter be used for these purposes?

Antimatter in contact with matter can in fact generate amounts of energy capable of propelling spaceships and reach a destructive power very superior to any other known to man. At a smaller scale, it could also be a source of clean energy to forever substitute oil, coal and all renewable energies. Antimatter would be an excellent source of energy, but only if it existed in large quantities around us. This, however, is not the case. Since there is not such a thing as a “mine of antimatter” in the universe, if we want to use antimatter, we have to produce it first. The problem is that the quantity of energy necessary to produce antimatter is very superior to the amount of energy obtained from the annihilation processes.

To this one may also add the difficulty in storing antimatter particles, since nowadays we don't have the technology to store even a trillionth of a gram of positrons.

Is there, then, any real utility for antimatter nowadays? The answer is yes. Antimatter has well known and well exploited medical applications, like the Positron Emission Tomography (PET). In this diagnostic technique, the gamma rays emitted during the annihilation of antimatter are used to observe the metabolism of the tissues. This is useful, for instance, for the localization of tumors.

What applications does antimatter have?