Mini-Throughput: Visiting the Neighbors Edition

Artists’ impression of proxima cen b. Credit: ESO/M. Kornmesser

In the constellation of Centaurus there is a small faint red star. It’s so inconspicuous, it wasn’t even discovered until 1915. But this tiny star — about a tenth the mass of the Sun and 500 times fainter — turned out to be the closest star to our own, only slightly closer than the much brighter Alpha Centauri binary, around which it orbits every 500,000 years.

In 2016, astronomers confirmed that Proxima Centauri has a planet. This planet is only slightly larger than the Earth and orbits its cold faint sun every 11 days. As it swings around its star, it gently pulls the star toward it, creating a very tiny shift in its light that astronomers were able to detect. Because Proxima is so faint, this planet is actually in a “habitable zone” where liquid water could exist. To be clear, Proxima Centauri b is probably not inhabited or inhabitable. Proxima is a flare star, which means it sends out blasts of radiation from time to time that dwarf the kind of flares our star puts out.

Well, we just confirmed the discovery of a second potential planet using two different techniques. This one is much further out and much larger — more of a Jupiter type. It’s massive and cold so unlikely to host life. But we’re now talking about a system of planets.

Now here’s where we really start venturing into science fiction: it’s possible that we could visit this planetary system by the end of the century.

Oh, not we humans. But possibly a space probe. At the same time that Proxima Cen b was discovered, a project called Breakthrough Starshot began with the goal of sending a probe to the Alpha Centauri system (of which Proxima is part). This isn’t quite science fiction. The idea is that you would build a very lightweight probe and attached to a massive solar sail. You would then illuminate that sail with massive lasers from the Earth, potentially building its speed up to an appreciable fraction of the speed of light, putting Proxima within a 20-30 year trip. The probes themselves would be cheap, so you could build hundreds of them, thus insulating yourself against accidents.

Yeah, it’s a crazy idea. But the Starshot people are quite serious about it. They’ve enlisted some big names and started asking the right kinds of questions of the right kinds of people. It’s the first proposal I’ve ever seen for interstellar travel that isn’t completely bonkers.

There’s obviously a long way to go before we send off our first interstellar probe. But we have a destination and a serious proposal on the table. And we have the money and the technology. It’s only a matter of time and will.