Bringing Supernova Explosions Down to Earth
Scientists at the University of Wales, Aberystwyth, are proposing to cut the immense power of a cosmic supernova explosion down to size with experimental simulations in their laboratory. Though supernovae are nuclear explosions, the way such explosions develop is similar in many ways to conventional chemical explosions, which can safely be detonated in specially constructed steel vessels in a laboratory.Dr Geraint Thomas, in association with an international team of collaborators, is planning to develop equipment and expertise in the Physics Department at Aberystwyth to stage a programme of precise experimental explosions to help astronomers understand supernovae better. The laboratory at Aberystwyth is one of only a handful world-wide with the expertise to carry out such an experiment.
Dr Thomas will describe the experiments he wants to do at the UK's National Astronomy Meeting at the University of Southampton on Thursday 10th April.
So-called Type IA supernovae are the brightest and most frequent type of supernovae observed. They are believed to be the result of the catastrophic nuclear explosions of white dwarf stars. When they go off, new chemical elements are created in the the nuclear processes they trigger, and material is blasted out into interstellar space along with prodigious amounts of energy in the form of radiation and particles. They become so bright, astronomers can use them as a means of gauging the distances to remote galaxies in which no other individual stars can be resolved. But to interpret their brightness correctly, scientists need to know more about the physical processes going on.
Dr Thomas points out, 'The gaps in our knowledge as to how supernovae actually explode leaves room for much uncertainty. But the similarity with combustion processes on Earth provides some opportunities since conditions representative of supernova explosions can easily be developed on Earth, allowing them to be studied in detail. This can provide valuable clues to the actual mechanisms that need to be included in the theory describing supernovae. The experimental findings will allow astrophysicists to confirm or modify their models of these explosions.' Burning in supernovae can propagate as a flame, or as a detonation, as can fires on Earth. Observations suggest that a supernova starts as a slow flame that may later become supersonic, setting off a detonation.
The experiments will also have more mundane spin-off, helping safety experts predict more accurately the severity of possible explosions so they can take appropriate precautions in the design of industrial plant, for example.
Dr Thomas's collaborators in this proposed project are Drs Alexei Khokhlov and Elaine Oran at the Naval Research Laboratory, Washington DC, Professor Craig Wheeler of the University of Texas and members of the Engineering and Mathematics Departments in the University of Cambridge, UK.