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ANU man in
team which
finds new
planet
By PETER POCKLEY
A young Australian scientist, Mat
thew Bailes, who completed his PhD
at the ANU only two years ago, has
shared in one of the most exciting
discoveries of modern astronomy —
the first planet to be found outside
the solar system.
Ever since the Polish astronomer
Nicholaus Copernicus displaced hu
mans from the physical focus of the
universe in 1543 by placing the sun,
instead of the earth, at the centre of
the solar system, people have conjec
tured that life might exist elsewhere
in the universe. But, planets like
earth, with natural conditions pro
tecting them from the harsh environ
ment of space, were needed to allow
life to flourish.
Intensive searches for planets else
where in the universe have been
fruitless until yesterday's dramatic
announcement in London.
Speculation that life might exist
beyond earth is suddenly given cre
dence, though this particular planet
is too far away to be observed direct
ly and is bathed in such intense radi
ation that life, as we know it, is
unlikely to exist on its surface.
Nonetheless, Professor Andrew
Lyne, the leader of the three-man
team which made the find, said in
London that the planet "opens up the
whole issue [of life beyond earth],
since it is reasonable to suggest that
there are other planets outside the
solar system which could sustain
life".
The planet's existence has been
deduced from accurate measurements
of the radio blips received from a
rapidly rotating neutron star (a pul
sar only 30km across and consisting
of such dense material that a sugar
cube of it would weigh 100 million
tonnes on earth).
It lies near the centre of our gal
axy, the Milky Way, about 30,000
light years from earth (a light year is
the distance travelled by light in one
year, equivalent to about 10 million
million kilometres).
Calculations show the planet is ro
tating in a nearly circular orbit
around the pulsar once every six
months at about the same distance
as Venus is from the sun (107 mil
lion kilometres — Venus lies be
tween the earth and the sun). The
planet is 10 times the mass of the
earth.
Dr Bailes returned to Australia on ■
Tuesday for a two-week session ob
serving pulsars at the Parkes radio
telescope with Dr Dick Manchester,
his former scientific supervisor while
he was studying for his PhD at the
ANU and Mt Stromlo and Siding
Spring Observatories.
Dr Manchester, Professor Lyne
and Dr Bailes were co-authors of the
cover-story paper in last week's Na
ture which announced the discovery
with the Parkes dish of a record
swarm of "millisecond pulsars".
It is the world-leading expertise in
study of pulsars by the Manchester
Lyne group which has made the dis
covery possible. A pulsar, discovered
in 1985 and known by its catalogue
number of PSR 1829-10, has provid
ed the clues to the planet's existence.
Speaking to The Canberra Times
in Sydney yesterday, Dr Bailes said
PSR 1829-10 was one of 40 pulsars
being studied by the team. Thir
ty-nine of them fitted conventional
explanations of pulsar behaviour but
team member Mr Setnam Shemar
noticed that the 40th had what is
called a "sinusoidal variation" in the
precise timing of its pulses. This is
exactly what would be expected if a
planet was circling the pulsar and
causing it to wobble.
Dr Bailes said the team then ob
served the pulsar every day they
could get time on the telescope for 18
months, finishing with continuous
observations for a month to confirm
the planetary hypothesis.
Because the planet cannot be seen
from earth, its effect on the spinning
of the pulsar can be seen in the
pulsar's "clock" of radio emissions.
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