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Fat-bottomed nucleii could help reveal what makes the world go round -- or, more accurately, help explain the inequality between matter and antimatter in the universe and therefore why the two have not annihilated one another.

Atoms are composed of protons, neutrons and electrons. By analysing the interactions between sub-atomic particles you can predict the overall behaviour of the atoms. The interactions also distort the shape of the atom's nucleus, usually into a sphere or a quadrupole form -- something akin to a rugby ball.


However, octupole or pear-shaped nucleii have been found in heavier elements from the Periodic Table such as radon and radium.

The search for these pear-shapes involved using particle accelerators at Cern's Isotope Separator On Line-Detector (ISOLDE) facility, which accelerated isolated isotopes to the energies needed for Peter Butler, a physicist at the University of Liverpool, and his team to conduct nuclear reaction experiments.

According to an article in Nature, the team found that


radium-224 takes the form of a pear, although "not an elongated conference pear, more like a short-necked comice or Anjou".

The octupole shape is of interest to scientists because seeking the forces which would lead to unequal quantities of matter and antimatter in the universe involves looking for the effects of those forces. One of these is a measure of the overall polarity of a charged system which is known as an electric dipole moment (EDM).

Pear-shaped nucleii would enhance the likelihood of observing EDMs because their composition enhances measurable EDM by a factor of around a thousand.