Stephen Hawking recently announced that he wants to send spacecraft to Alpha Centauri.
Image from Bryan Bedder/Getty Images for Breakthrough Prize Foundation.
Hawking made the announcement with Russian entrepreneur Yuri Milner on April 12, 2016 as part of the Breakthrough Starshot Initiative.
"I believe what makes us unique is transcending our limits," said Hawking, as reported by Ars Technica.
This is huge because while Alpha Centauri is the star nearest to Earth (besides the sun), it’s still more than four light years away.
View of Alpha Centauri from the Digitized Sky Survey 2. Image from ESO/DSS 2/Wikimedia Commons.
That's 25.6 trillion miles! To put that in perspective — if we magically shrank space to the point where the sun was just the size of a ping-pong ball, Alpha Centauri would still be nearly 800 miles away.
The biggest obstacle to achieving this journey so far has been that we don't have a spacecraft that can go anywhere near fast enough.
Image from Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Wikimedia Commons.
The New Horizons probe that NASA just sent past Pluto is traveling at an eye-watering 36,000 mph, but it would still take it 70,000 years to reach Alpha Centauri.
So that’s why — according to Hawking — we’re going to build new spacecraft. Tiny spacecraft.
Yuri Milner holding an example of one of the chips that could be the brains of each probe. Image from Bryan Bedder/Getty Images for Breakthrough Prize Foundation.
Instead of one large ship, the plan is to launch thousands of small gram-sized probes. The idea relies on computer chips becoming increasingly smaller and more powerful over time — a trend that so far has held true.
We're going to build tiny spacecraft ... powered by LASERS.
GIF from Breakthrough/YouTube.
Each probe would fly behind lightweight reflective sails — known as lightsails. The lightsails would catch light from big arrays of lasers here on Earth, which could provide propulsion (the probes themselves, meanwhile, could be powered by small radioactive batteries).
These tiny spacecraft powered by lasers could — theoretically — get from Earth to Alpha Centauri IN JUST 20 YEARS.
GIF from Breakthrough/YouTube.
The lasers could accelerate the craft to speeds over a thousand times faster than what any current spacecraft are capable of, says Breakthrough. They predict they could get the mini-probes traveling up to about 20% the speed of light.
Of course, yes, it'll take time to get this project up and running — about 20 years just for that — and then another 20 years for the craft to get to Alpha Centauri, followed by a nail-bitingly agonizing at least four-year wait to send any pictures the probes take back to Earth.
The price tag on this project? A cool $100 million.
Getting these mini-craft working won't just be cool — they could help prove that lightsails are a good idea.
Artist's concept of a lightsail craft. Image from NASA/Wikimedia Commons.
There are many challenges ahead for Breakthrough's mini-craft, like how to actually even send signals back to Earth from such a distance, but if the project is successful, it has a couple benefits. The mini-craft could take pictures of alien worlds, for instance.
But the biggest benefit could be the proof-of-concept test of the lightsails. If they work, they could become commonplace, helping us explore the solar system and the universe beyond.
But for today, the most important part of the announcement is that it’s about always reaching for the stars — and that's a very good thing indeed.
Image from Jemal Countess/Getty Images.
"Earth is a wonderful place, but it might not last forever," said Hawking in a statement reported by ABC News, “Sooner or later, we must look to the stars. Breakthrough Starshot is a very exciting first step on that journey.”