WE NEED TINY SPACESHIPS. LOTS OF ‘EM.
The dramatic announcement that a small rocky planet might exist in the nearest star system to the sun, Alpha Centauri, raises the hope that we might be able to send probes to an alien world in our lifetimes.
These spacecraft might rely on giant lasers for propulsion to reach more than 25 percent of the speed of light, according to the $100 million Breakthrough Starshot project unveiled earlier this year. Now scientists calculate how much damage such probes might face on their interstellar voyages.
The Alpha Centauri system consists of three stars — Alpha Centauri A, Alpha Centauri B, and the closest star to the sun, a small red dwarf named Proxima Centauri.
Astronomers announced Wednesday that Proxima Centauri appears to be home to a rocky planet, Proxima b, about 1.3 times the mass of Earth in the star’s habitable zone (the area around the star warm enough for the planet to potentially host liquid water on its surface).
The researchers say one way to protect these probes would be to streamline them to needle-like shapes and fold up their sails after launch to minimize the chances of the spacecraft hitting obstacles.
They also suggested adding protective layers onto the probes, such as graphite armor up to 3 mm thick. In addition, the scientists noted that some probes could clear the way for their brethren by reflecting some of the laser light used to propel the spacecraft onto incoming specks of dust, brushing them aside.
One hope for Breakthrough Starshot is that it finds a new home for humanity. “The lifetime of Proxima is several trillion years, almost a thousand times longer than the remaining lifetime of the sun,” Loeb says. “Hence, a habitable rocky planet around Proxima would be the most natural location to where our civilization could aspire to move after the sun will die 5 billion years from now.”
Hoang, Loeb and their colleagues detailed their findings online Aug. 18 in a paper submitted to the Astrophysical Journal.