Silicon Valley billionaire to give another $100 million in ET search

Yuri Milner, the Silicon Valley billionaire who has already committed $100 million to scientific efforts seeking radio evidence of alien life in the universe, announced Tuesday he is adding a second $100 million to expand the quest by sending swarms of tiny robot spacecraft into interstellar space.

The one-time Moscow physicist envisions thousands of ships he calls “nanocrafts,” someday speeding at 100 million miles an hour to stars light-years away, powered only by the pressure of light beams from arrays of space-borne lasers.

Under the Berkeley program, astronomers at the National Radio Astronomy Observatory at Green Bank, W.Va., have begun scanning “a few hundred stars” for SETI radio signals, said Andrew Siemion, an astronomer at the project in Berkeley.

[...] the new telescope at UC’s Lick Observtory near San Jose, known as the Automated Planet Finder, has been programmed to scan for strange optical signals that could be coming in laser beams from ET, Siemion said.

A single chip, for example, by then would be a “gram-scale wafer” weighing less than an ounce carrying miniaturized cameras, thrusters, power supplies, and systems for navigation and communication, he said.

The tiny spacecraft would carry huge, lightweight sails — “each no more than a few hundred atoms thick,” he said — propelled by the pressure of light beams from phased arrays of earth-bound, mountaintop lasers generating hundreds of millions of kilowatts at a time.

Milner proposes sending the first fleet of hundreds of tiny spacecraft to hunt for SETI signals from planets around Earth’s closest stars, the Alpha Centauri star system, which is 25 trillion miles, or 4.37 light-years away.