University of  Sussex MEDIA RELEASE

The Information Office, University of Sussex, Falmer, Brighton, BN1 9RH.

5 February l998 For immediate release


Sussex University is at the forefront of a new discipline which has emerged from a collision between astronomy and particle physics. The new field, which was legitimised as a subject by the Particle Physics and Astronomy Research Council only last year, is known as 'particle cosmology'. Sussex now boasts the largest research group in the UK to be working in this subject.

Dr Jim Lidsey, the world's first official particle cosmology research fellow, is based in the Astronomy Centre and the Centre for Theoretical Physics in the School of Chemistry, Physics and Environmental Science at Sussex. He describes the work of the group as studying what happened in the first fraction of a second after the Big Bang, approximately ten billion years ago. The first hot and energetic moments of the universe just 10-36 seconds after the beginning can be discussed by employing the language of elementary particles physics.

Dr Lidsey and the team study theoretical models of the very early universe and project them into the future. Comparing how the universe should be with how it actually looks is a reliable method of testing theories about what has happened since the Big Bang. This link between the study of the very small (particle physics) and the very large (cosmology) has given rise to 'particle cosmology'.

Dr Lidsey works on a scenario known as 'cosmological inflation', which might explain why the universe is expanding and how the galaxies formed out of the primordial universe. The expansion of the universe can be described by the 'raisin bread' analogy. The raisins represent galaxies, which change position as the loaf bakes, or as the universe expands. Although the raisins don't really move around the dough, they become further apart as the dough rises. This explains why galaxies appear to be receding from us.

During inflation, distant objects can actually move away from each other faster than light. Without inflation it is difficult to explain the universe's uniform temperature (2.7 degrees above absolute zero), as you would expect some parts of the loaf to be warmer than others. However, current theory suggests that this constant temperature can be explained if the universe did indeed inflate during that brief moment after the Big Bang.

"Particle cosmology uses the universe as a giant magnifying glass to look at the smallest scale in order to imagine what the universe was like in the distant past, " says Dr Lidsey. His new book, The Bigger Bang, is to be published by Cambridge University Press later this year.

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For further information please contact Dr Jim Lidsey on 606755 ext 2430, e-mail:, or Laura Miles, Information Office, tel: (01273) 606755 ext. 4353, fax: (01273) 678335, e-mail:

This file produced by USIS - 6th February 1998