Astrophysicist Stephen Hawking and businessman Yuri Milner recently announced a $100 million plan to send a series of small probes to the Alpha Centauri star system. This would be the first mission ever by the human race to another star system.
Alpha Centauri is far different from our own sun. Unlike our own celestial family, the Alpha Centauri star system contains three stars.
The Starshot Project envisions the launch, decades from now, of around 1,000 miniature spacecraft in a single payload. Each of these tiny craft would unfurl a lightweight solar sail. Powered by powerful lasers on Earth, these smartphone-like robotic observers would be accelerated up to 20 percent of the speed of light in just 2 minutes.
"What makes human beings unique? I believe that what makes us unique is transcending our limits. Today we commit to the next great leap in the cosmos, because we are human and our nature is to fly," Hawking said at a conference announcing the project.
Breakthrough Starshot is a proof-of-concept program designed to test if needed technology could work on a mission to the nearest star system.
"The Alpha Centauri star system is 25 trillion miles (4.37 light-years) away. With today's fastest spacecraft, it would take about 30,000 years to get there. Breakthrough Starshot aims to establish whether a gram-scale nanocraft, on a sail pushed by a light beam, can fly over a thousand times faster," Breakthrough Initiatives stated on its website.
Such a mission would not be completed during the lives of many people alive today, as it would take at least 45 years for data from Alpha Centauri to be received by researchers on Earth. Technology for the mission will likely take about 20 years to develop and build. After that, the vehicles would take roughly 20 years to reach their destination. Finally, five years would elapse as the radio signal, traveling over 186,000 miles per second, would traverse the vast distance back to Earth.
When the surviving diminutive spacecraft will arrive at their destination, 4.37 light-years from our own, they will record images and record data, studying the star system. Afterwards, the tiny vehicles will continue to race past our nearest stellar neighbor.
The smallest of the three stars in the system, Proxima Centauri, is actually the closest star to Earth, apart from the sun. However, it is extremely small – just 50 percent more massive than Jupiter. In 2012, astronomers found evidence of a possible planet orbiting around the second most massive star in the system. That world orbits around its sun once every three days and six hours, making the chance of finding life on the world slim.
With three stars in the system, any planetary orbit, except those closest to their respective stars, may be erratic. Such an arrangement makes life less likely to develop than in solar systems having just a single sun.
Alpha Centauri may not provide the most likely stellar target to discover alien life. However, that does not mean our nearest stellar neighbor is not worthy of a visit. Differences between that system and our own mean even if finding alien life there is improbable, the fleet of spacecraft will give humans a chance to see a solar system far unlike our own, up close and personal.