Sunday, April 10, 2005
Will ET signal us by opening and shutting the Venetian blinds?
The search for extraterrestrial intelligence (SETI) could be taking the wrong approach. Instead of listening for alien radio broadcasts, a better strategy may be to look for giant structures placed in orbit around nearby stars by alien civilisations.Back to semaphore code for interstellar communications?
"Artificial structures may be the best way for an advanced extraterrestrial civilisation to signal its presence to an emerging technology like ours," says Luc Arnold of the Observatory of Haute-Provence in France. And he believes that the generation of space-based telescopes now being designed will be able to spot them.
Arnold has studied the capabilities of space-based telescopes such as the European Space Agency's forthcoming Corot telescope and NASA's Kepler. These instruments will look for the telltale dimming of a star's light when a planet passes in front of it.
They could also identify an artificial object the size of a planet, such as a lightweight solar sail, says Arnold. His work will be published in The Astrophysical Journal.
Arnold has determined the characteristic transit signal that differently shaped objects would produce, including a Jupiter-sized equilateral triangle and a louvre - parallel slats with gaps between them.
Corot and Kepler will be capable of distinguishing these objects ... [New Scientist]