Artist's impression of the SKA's dense aperture array antennas.
Credit: Swinburne Astronomy Productions/ SKA Program Development Office.
SYDNEY: As more Earth-like planets come into view from space-based observatories, a proposed giant radio telescope on the ground could help us learn more about their origins and whether they harbour life.
The Square Kilometre Array (SKA) telescope, an array of 3,000 radio antennas linked across several thousand kilometres to be built in either South Africa or Australia-New Zealand, will aid the search for extraterrestrial intelligence.
Once operational in 2020, the SKA will listen to the cosmos for faint radio signals dispatched from far-away alien civilisations.
The radio telescope’s listening power will expand the volume of the galaxy that can be searched for alien radio transmissions by a factor of 1,000, using a greater range of frequencies.
“More stars can be monitored for radio stations on other planets,” said Charles Lineweaver, an astronomer at the Australian National University in Canberra. “The SKA will be a set of bigger ears to listen to the universe.”
Detecting an alien radio signal
Physicists first dreamt up the idea that large radio telescopes on Earth could detect extra-terrestrial radio signals from distant planets and star systems in 1959.
Two years later, American-born search for extra-terrestrial intelligence (SETI) pioneer Frank Drake developed an equation to predict the number of communicative civilisations in our galaxy.
The Drake Equation is considered an effective way to organise the criteria needed for technologically advanced alien beings to exist, but relies on several unknown variables.
“I am sceptical about the prospects of finding extra-terrestrials with the human-like intelligence to construct radio emitters, but I think we should keep looking,” said Lineweaver. “In the past, whenever we have built a new instrument to search unexplored regions of the universe, we have found something.”
Looking for planet growth
When built, the SKA will also have the capacity to map the early evolution of terrestrial planets.
“At the moment we can only view the early stages of planet formation in a few nearby stars, but this is a process that takes millions of years,” said Simon Ellingsen, an astrophysicist from the University of Tasmania who studies star formations.
With dishes spread across an entire continent, the SKA will scan the habitable regions of stars more than 500 light years away to observe the first 50 million years in the timeline of terrestrial planets, when their mass, orbit, composition and tilt are determined.
“The SKA’s sensitivity will allow us to look at more stars with a range of stages to see further back and fill in the holes of planetary formation,” Ellingsen said.
Since 1995, more than 500 extrasolar planets have been discovered and with incoming data from space-based satellites such as NASA’s Keplar, astronomers say it won’t be long before Earth-like planets are confirmed inside their star’s habitable zone – a region where liquid water could exist on a planet’s surface.
Understanding how planets form inside this habitable zone is a key question in the search for life like ours elsewhere in the galaxy, said Ellingsen.
Radiotelescopes !.
Build them in Australia because,
all other continents will be affected in the 3rd World War.
Arne Strand. Sweden.