Australasian Science: Australia's authority on science since 1938

Stars Above, Energy Below

By Stephen Luntz

Outside her research on the birth of the first stars, Rachel Webster is working on the use of geothermal energy in Victoria’s coal fields and running programs to support women in science.

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Prof Rachel Webster is a leading figure in Australian astronomy research. However, her latest work sees her seeking clean energy sources beneath our feet.

Webster says she was “always interested in science” and decided at 7 or 8 she would become a physicist. At 17 she went on a science camp. “There was a guy lecturing on cosmology and I thought, ‘Yep, that’s what I will do’,” she says. A degree in pure maths from Monash was followed by a Masters at Sussex University and a doctorate at Cambridge.

Webster’s thesis was on gravitational lensing, the study of distant objects whose light has been focused by the gravity of intervening galaxies so that they appear larger and brighter than they otherwise would. “I have a longstanding interest in using lensing to map the distribution of dark matter,” says Webster, who is now based at the University of Melbourne’s Physics Department. Since light is bent further when a greater mass exists between us and the object being observed, substantial bending can be used as an indication of the presence of mass we cannot otherwise see.

This use for gravitational lensing is in addition to its more common application as a “natural telescope”. “I’ve developed a technique to measure the size of the emission regions of quasars. These are scales of about a millionth of an arc second, so three orders of magnitude smaller than...

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