When the Internet billionaires Yuri Milner and Mark Zuckerberg proposed sending a mission to another solar system, it was hard to separate vision from bluster. Was the idea a plausible next step in mankind’s exploration of space? Or an ego-driven challenge to other space-oriented billionaires — especially Elon Musk and his dreams of colonies on Mars?
Anyone, after all, can talk about going to the stars. But they’re really far away. The distance to the nearest star system, Alpha Centauri, is 4.4 light years. That’s something like 26 trillion miles. To put it in perspective, it took the New Horizons spacecraft nine years to reach Pluto. A craft going the same speed would reach Alpha Centauri around 11000 AD. Zuckerberg and Milner propose completing that 9,000-year trip in 20 years.
