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Could Stephen Hawking Really Use Lasers to Get to Alpha Centauri?

When he’s not busy playing Quantum Chess with Paul Rudd, famed astrophysicist Stephen Hawking is busy planning an interstellar adventure. At a news conference, Tuesday, Hawking, along with Russian billionaire Yuri Milner, announced a new initiative to visit Alpha Centauri, the second-closest star to Earth, within our lifetimes. It sounds bold and exciting, but is it really possible?

Breakthrough Starshot” is the latest venture of the Breakthrough Prize Foundation, a Silicon Valley-funded group known for its monumental financial awards. The plan is to use an initial $100 million to engineer a proof-of-concept fleet of “nanocraft”: ultralight, iPhone-sized spacecraft that could move through space under sail power, pushed along by the force of light particles.


Lightsail works by bouncing photons using a reflective sail. Source: The Planetary Society

The hypothetical spacecraft (currently dubbed “StarChip”) will be built out of a “gram-scale” silicon wafer, complete with onboard camera, photon thrusters, power supply, and a navigation and communication system.

“For the first time in human history we can do more than just gaze at the stars, we can actually reach them,” Milner told the crowd during the conference. In theory, these nanocraft could test for habitable conditions on planets within Alpha Centauri’s system, but the tough reality is that getting there is a far reach (ba-doom-chh) at best.

Alpha Centauri is located some 4.37 light-years (25 trillion miles) away from Earth. And while the current record holder for most distant spacecraft, Voyager 1, is technically meandering through interstellar space, it will take some 40,000 years to pass by another fireball. For Hawking and Milner’s StarChip fleet to reach Alpha Centauri within one generation, it will have to travel roughly 2,857 times faster than any industry spacecraft, and be able to maintain that speed for 20 straight years.

There’s another challenge at hand: while Lightsail technology is currently in development, the long journey between stars is met with few photons to do the heavy pushing. Even if this weren’t the case, a sun’s light isn’t strong enough to propel the craft along with the necessary efficiency. The team plans to sideskirt this by introducing a very, very big laser. Or rather, an array of very big lasers that will power the craft from the ground in Sector 2814.


Is it all possible? Eventually, sure. But as Milner explains, there is absolutely no way to predict how long this kind of tech will take to get off the ground. In the meantime, the team has their eyes set firmly on the prize, and – at least in Milner’s case – their wallets open.

“I believe what makes us unique is transcending our limits,” added Hawking. “Gravity pins us to the ground, but I just flew to America. Today we commit to this next great leap into the cosmos because we are human and our nature is to fly.”

Of course, even if the project doesn’t make its starshot goals, that doesn’t make it a wash. There are plenty of discoveries to be made as the team works through the impressive list of engineering challenges ahead. Starshot’s R&D could lead to breakthroughs in materials science, lightsail spaceflight, and optics (among other areas), and the team has expressed interest in working with NASA to solve the technical hurdles.

“The space between here and Alpha Centauri is not empty,” added physicist Freeman Dyson, who made the announcement alongside Milner and Hawking. “There are billions of planets [and] trillions of comets and asteroids.”

How far will the Starshot initiative get? We’re just going to have to wait to find out.


IMAGES: The Planetary Society, Breakthrough Society/YouTube

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