Future observatories, such as the Square Kilometer Array proposed for development in Australia or southern Africa, could detect Earth-like planets ten times farther away, which would encompass 100 million stars.
If radio emissions were detected from a distant planet, additional observations could tell astronomers about the host star's mass, the orbit of the planet, and the distance between the two, Loeb noted.
"That by itself would allow us to decide whether there could be liquid water on the surface of the planet and whether that can support life as we know it," he said.
(See a gallery of what life on other planets might look like.)
Peter Backus is the observing programs manager at the SETI Institute in Mountain View, California. He said the institute's radio telescope under construction in northern California is also exploring new regions of the frequency spectrum.
"Just as [Loeb]'s paper talks about the low-frequency end, we're expanding up to higher frequencies that really haven't been searched at all," he said at the briefing.
Previous searches looked at the frequency range between 1,200 and 3,000 megahertz.
The new telescope, named the Allen Telescope Array after its primary donor, Microsoft cofounder Paul Allen, will go up to 11,200 megahertz, Backus said.
Preliminary tests reveal that nearly 90 percent of that band is available to detect extraterrestrial transmissions.
The array configuration will also allow simultaneous examinations of several patches of the sky.
"That gives us a lot of flexibility in what we can do and how much we can do at one time," Backus said.
Ultimately the array will consist of 350 20-foot (6-meter) dishes spread out over 2,300 feet (700 meters). Currently 36 of the antennas are online with 42 expected to boot up this summer.
Though originally conceived as a telescope primarily for SETI, Backus said radio astronomy projects will direct where the array points. Within the field of view are bound to be several of the million or so SETI candidate stars.
"Although a certain fraction of the time we'll have to point the array to follow up on result candidates," he noted.
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