Guest speaker
at the November meeting Jonti Horner, Vice Chancellor’s Senior Research Fellow,
gave a talk entitled “U.S.Q., Toowoomba and Life Elsewhere”. The idea of life outside
Earth started with the erroneous idea that there were canals on Mars. But there
are several places in the Solar System that have the necessary requirements for
life: a solvent like water, nutrients; and energy, e.g. our Sun. Europa, one of
Jupiter’s moons, has an ocean about 100 kilometres deep, with volcanism on the
bottom, but there is an outer layer of ice 10-20 kilometres thick that prevents
us from detecting any possible life below.
In the past
Mars had lots of water, and even now there is ice water underground under
intense pressure. Any life there would be primitive life like bacteria. But
exoplanets, i.e. planets around other stars, are the main emphasis now. These
can be detected in a number of ways. The presence of a planet produces a slight
wobble in the motion of a star. And there is a tiny dimming of a star when a
planet transits in front of it. Spectral lines, representing the emission lines
of elements in a star, are subject to the Doppler effect caused by the star and
planet moving towards and away from Earth in their orbit.
Pulsars are ultra-dense neutron stars, which are
spinning very rapidly. The pulsar’s radiation is focused into a beam by the
pulsar’s strong magnetic field. This blip is regular, but the presence of a
planet causes it to occur earlier or later. The Kepler Space Telescope, which
was launched in order to detect exoplanets, surveyed only one patch in the sky.
NASA’s Transiting Exoplanet Survey Satellite, when launched, will target all
the brightest stars in all of the night sky. Exoplanet detection needs more
telescopes. MINERVA is a four-telescope array in Arizona looking for exoplanets
in the northern hemisphere. USQ is building a complementary MINERVA multi-telescope
facility at Mount Kent. The number of exoplanets discovered has been increasing
exponentially, and they have been finding more that resemble Earth.
(Report by Mary Petr)
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