From: | Doug Roberts |
Title: | NEW TELESCOPE TO LISTEN FOR TV FROM SPACE |
Source: | Sunday Times |
Date: | January 28, 1996 |
AN AMBITIOUS plan to look for intelligent life on other planets and peer into
black holes with a radio telescope the size of 150 football pitches emerged in
Britain last week.
Scientists who met at Jodrell Bank in Cheshire, where the first radio telescope
was built 50 years ago, said the new instrument would be hundreds of times more
sensitive than today's most powerful telescopes.
Unlike the Hubble space telescope, it will be able to focus on extremely faint
sources of radiation emanating from distant stars and galaxies. As a radio
telescope, it will also exploit a far broader range of the radiation spectrum
than Hubble, which detects only light.
The telescope, to be built over the next 15 years, will cover an area of 11m sq
ft, and measure nearly three quarters of a mile accross. It will be able to
detect radio signals from about 15 billion light years away - the outside edge
of the universe. Because this radiation has taken billions of years to reach
Earth, scientists hope it will provide new evidence about the Big Bang, the
primordial explosion thought to have created the universe.
"This allows us to see these galaxies at the time when they were forming. We
should be able to look back to 90% of the age of the universe. We don't know
exactly what we'll find." said Dr Robert Braun, an astronomer at the national
astronomy foundation in the Netherlands.
Dr Peter Wilkinson, a Jodrell Bank scientist who helped to organise last week's
summit, said one of the more ambitious objectives was to search for any
artificial radio signals eminating from the broadcasts of intelligent lifeforms
on other planets.
Present radio telescopes would only detect strong alien transmissions that were
deliberately sent in the direction of Earth, said Wilkinson. "If you had an
enormous telescope then you could pick up other transmissions, for instance if
they had radio or TV broadcasts. If other civilisations had a big telescope
looking at us they could tell there is something unnatuaral here just by our
radio and TV broadcasts."
Dr John Dreher, and American astronomer involved in the search for
extraterrestrial intelligence, said the new telescope would be sensitive enough
to detect TV-like broadcasts of alien life living between 10 and 20 light years
away. The giant telescope will eventually be linked electronically to smaller
radio telescopes in orbit around Earth to create a network of radio telescopes
with an even wider collecting area. This will enable astronomers to separate
two distant sources of radiation that are so close as to be indistinguishable
with conventional telescopes on Earth.
Wilkinson said one of the most important objectives of the new telescope was to
search for black holes, intensely violent areas formed by collapsed stars with
such strong gravitational fields that all nearby matter and even light is
sucked in. "We want to find out whether there is a black hole at the centre of
every galaxy, including out own," he said.
Traditional optical instruments, such as the Hubble telescope, are hampered in
their search for black holes by massive dust clouds which obscure their view.
Unlike light, however, radio waves can penetrate dust, enabling radio
telescopes to "look" inside black holes.
Because the new telescope will be 200 times bigger than Jodrell Bank,
strikingly different technology will have to be applied. Instead of one giant
steel dish, scientists envisage hundreds or even thousands of dishes, each
computer-controlled to focus on the faintest radio waves from distant starts.
Some scientists believe the telescope should be sited in Britain, because of
its distinguished history of radio radioastronomy, dating back to the discovery
of Radio Waves in space by Sir Bernard Lovell in 1947. Others favour rural
central Eurpoe or the desert of the Australian interior, where there is less
risk of radio interference from built-up areas.
The astronomers who met last week will draw up a detailed financial ploposal
over the next two two years to secure a 100-200m ukp to build the instrument.
It will come about through international collaboration, as the project is too
big for any one country.