2.5 History of Antimatter’s Development

Albert Einstein’s theory of relativity was the main instigator into the development of antimatter.  In particular, the relationship between mass and energy founded in the relativity equation,

(1)

would imply that a “negative energy solution” exists and would have significance on the electron [2].  From this equation, Paul Dirac -British theoretical physicist and Nobel laureate- concluded in 1931 that the negative energy represented in the equation must come from the existence of an particle that is of “the same mass and opposite charge to an electron” [2].  This final deduction led to the emergence of the antielectron.  In addition, it logically follows that as the electron is balanced from the proton, “a similar duality had to hold for…the proton” [2].

The proof of the existence of the antielectron came about by pure chance as Carl Anderson - American physicist and Nobel laureate-  was performing an experiment in 1930 using “a cloud chamber to study the radiation from a radioactive source” in California [2].  In his experiment, he found tracks of electron-like particles whose motion was acting like a proton, which the particle was dubbed “positron” [2].  The connection between the positron and the antielectron was not overlooked by scientists.  Two European scientists, Patrick Blackett - British physicist and Nobel laureate- and Giuseppe Occhialini –Italian physicists and Nobel laureate- , devised a modification to the cloud chamber in 1931 to take more accurate readings of cosmic ray tracking [2].  This modification allowed the two scientist to see “V-shaped pairs of tracks”, evidence of an electron-positron trail, which led to the calculation of the positron’s mass, which was deducted in 1932 to be the same mass as the electron [2].  Proving that the positrons found in the tracks was the antielectron that Dirac had theoretically deducted earlier. 

            With the development of the Bevetron, a machine that could “collide two protons together at an energy of 6.2 GeV,” by Ernest Lawerence –Nobel laureate- in 1954, the stage for the discovery of the antiproton was set [14].  In 1955, Emilio Segrè - Italian American nuclear physicist and Nobel laureate- and his group of scientists, with the special device that Segrè and Owen Chamberlain -American physicist and Nobel laureate- developed to detect the antiproton, discovered the antiproton and later the antineutron [14].

The question remained, however, if antiparticles could combine into antimatter, constituting an antiatom.  Thus, an experiment was carried out to see if antiprotons would stick to antineutrons like protons stick to neutrons.  This experiment was conducted by two physicists working together, Antonino Zichichi and Leon Lederman, who simultaneously developed the antideuteron in 1965 [14].  The next part to answer this question was to see if antielectrons stick to antinuclei as to constitute an antiatom.  This particular experiment was recently carried out in 1995 by a team of Cern researchers who successfully developed 9 antihydrogens [14].  Thus, the existence of antimatter was realized.          

While the existence of antimatter and its potential to create a more potent energy resource has been discovered and carefully documented, a lingering question remains on how this system would react in a real world situation.  To elaborate, there have been numerous ideas for an engine design using antimatter as a propellant; however, real test have not been conducted on actually using antimatter in such an engine.  Thus, there exists a need to test these ideas to see the practicality of such a design. 

Consequences | History of Antimatter Development | Air Force Involvement in Antimatter Propulsion