Mankind has a history of insatiable curiosity – from our ancestors leaving Africa, taking to the skies and now venturing into space. However, even cutting-edge current rocket propulsion technology means it would take tens or hundreds of millennia to reach our neighbouring star system, Alpha Centauri.
Within Alpha Centauri is the star Proxima Centauri or Proxima c.
Proxima b is only a candidate. This is very important to underline
Proxima c is 4.25 light-years away and orbiting it is Proxima b – a planet similar in size to Earth and far away enough from the star for conditions conducive to life.
Dr Mario Damasso of Italy’s Observatory of Turin believes both Proxima b and Proxima c present the most realistic hopes of colonising new worlds outside of our Solar System.
He said: “It is only a candidate. This is very important to underline.”
Breakthrough Starshot: The program aims to propel explorers to new solar systems
Breakthrough Starshot: Alpha Centauri is our neighbouring star system
Breakthrough Starshot – is a groundbreaking project founded by the late legendary physicist Professor Stephen Hawking, billionaires Yuri Milner and Facebook’s Mark Zuckerberg.
Breakthrough Starshot could see a small spaceship powered by ground-based lasers theoretically reach 20 percent of the speed of light – 134,123,326 mph (215,850,569kmh) – meaning the incomprehensible distance could be completed in only 40 years.
The technology has already been proven to work, with both NASA and the Japanese space agency (JAXA) having flown light sail missions.
And the privately-funded Planetary Society is currently operating a light sail in orbit around Earth.
Professor Grover Swartzlander from the Rochester Institute of Technology, told Physics.org: “The technology is advancing.”
Laser-based propulsion can achieve far greater acceleration than solar-based propulsion.
However, one concern is that the sail can drift out of alignment with the laser beam.
But Professor Swartzlander’s team has discovered a way to maintain alignment using diffraction gratings.
Instead of reflecting the laser light, their sail transmits the light at an angle.
Breakthrough Starshot: The craft is theoretically capable of travelling 20% the speed of light
The Sun rises over the horizon in this image from LightSail 2 shot in Sept 2019
The deflected light exerts both a forward force to propel the sail and a sideways force to keep it aligned.
However, carrying a larger and heavier human crew is a far more difficult problem.
Because it would take thousands of years to complete the 40 trillion mile journey, scientists have now established the concept of a “generation ship”, where people are born, reproduce and die on the spaceship.
Andreas Hein, executive director of the nonprofit Initiative for Interstellar Studies, told One Zero: “We know people can live in isolated areas, like islands, for hundreds or thousands of years; we know that in principle people can live in an artificial ecosystem.
“It’s a question of scaling things up. There are a lot of challenges, but no fundamental principle of physics is violated.”