The universe seems to have no antimatter. Antimatter is needed to balance the matter that is all around us. Physicists at the University of California have decided to try and find out why antimatter method behaves differently in gravity than matter and this may answer the missing antimatter question.
The antimatter version of the electron is the positron. Researchers took the first step towards measuring the freefall of positronium (a bound state between the positron and electron). If a positron and electron meet each other they produce two gamma rays. An electron and positron were first separated and the unstable system stabilised long enough to resist annihilation so that the effect of gravity could be measured on it.
A Rydberg state was produced by using lasers. In this state the atoms properties become exaggerated. The lifetime of the positronium was increased by a factor of 10 to 100. In the future scientists want to increase this to a factor of 10,000 which will create conditions for closer study. They will then look at the deflection to see how gravity affects the positronium.
If the antimatter and matter don’t behave in the same way it would be a shock to the physics world. At the moment it is taken that matter and antimatter are exactly the same. This is because there is the assumption that at the big bang both were produced in equal amounts. There is not much antimatter in the universe though which contradicts this and scientists are searching for differences between the two which would be a more plausible explanation. This experiment may explain the difference once and for all.