Australasian Science: Australia's authority on science since 1938

Big Bang Conundrum

By Stephen Luntz

An unexpected consistency in the concentration of deuterium atoms in the distant universe might be a curious coincidence, or it could rewrite our understanding of the Big Bang.

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Deuterium atoms, which combine a neutron with the proton and electron of an ordinary hydrogen atom, were formed during the Big Bang. To the best of our knowledge no natural processes since then have created any more, while on the other hand deuterium is sometimes destroyed within stars.

Cosmologists are interested in finding out how much deuterium was initially created in the Big Bang. In the youngest galaxies we can observe it at about 30 parts per million hydrogen atoms.

Besides existing in atomic form, deuterium can bond with ordinary hydrogen atoms to form hydrogen–deuterium (HD) molecules. The concentration of these HD molecules in distant galaxies has shown an unexpected and unexplained consistency. The researchers who discovered this think it’s merely a coincidence borne from a small sample size, but it’s just possible they have stumbled on a pattern of great significance.

Isaac Asimov once said: “The most exciting thing to hear in science is not ‘Eureka!’ but ‘That’s odd’”. It’s certainly what Dr Michael Murphy of Swinburne University’s Centre for Astrophysics and Supercomputing and PhD student Adrian Malec thought when they compared the concentration of HD molecules with molecular hydrogen (H2) in four distant parts of the universe.

In all four cases the HD shows up as roughly 30 parts per million hydrogen molecules. This is strange...

The full text of this article can be purchased from Informit.