The most easily identifiable star in the southern night skies, Alpha Centauri, could be scanned up close by a cloud of microprobes in a radical plan launched in the US last night.
Alpha Centauri is the striking yellow star that is also the brightest of the two pointer stars to the Southern Cross, alongside silver star Beta Centauri. The pointers, like the cross, never set as seen from southern Australian cities and towns and are unmistakable whether they are low above the southern horizon or close to directly overhead at different hours.
(They appear in the SE corner of the sky early in the evenings at this time of year.)
Alpha Centauri, like its distant co-pointer, is on closer examination a multiple star system. Its two components, one slightly larger than our Sun, and the other somewhat smaller but nevertheless very bright, form a binary system, in that they orbit a common point between them rather than one orbiting the other like the Moon orbits the Earth.
In their vicinity, a third star, an ‘angry’ flare-prone red dwarf called Proxima Centauri hasn’t been proven to be bound to them by gravity, but while invisible to the naked eye from Earth, it is actually the closest star of any type to our planet other than our Sun.
Until the entrepreneur Yuri Milner, offered to fund project ‘Breakthrough Starshot’, the conventional wisdom was that it would take a mission based on 21st rocket technology tens of thousands of years to travel across the 4.3 light years wide gap to Alpha Centauri.
Backed by cosmologist Stephen Hawking and privacy’s champion, Mark Zuckerberg, Milner’s project would use a yet to be perfected earth based laser booster to propel computer chip sized microprobes to 20 percent of the speed light within hours, and hurl them past the orbit of Pluto in three days, in the direction of Alpha Centauri, which they would reach in around 22 years, and sent back data which would take 4.3 years to reach Earth, making it a 26 year trip in terms of delivering results.
That’s little more than twice as long as it has taken some missions to Saturn, Comet Churyumov-Gerisamenko and Pluto and Charon to reach their targets.
The mass produced microprobes would be comparatively cheap to make, so the perils of their passage, outlined in this Space.com explainer, might destroy all but a few of a cloud of 1000 Starchips yet deliver humanity its first detailed insights into another star system that might harbor planets, perhaps one like ours.
Some of us might be alive to see what exists around Proxima as well as the major binary stars, which are sufficiently far apart to allow in theory stable planetary orbits about each, or even some ‘weird’ orbits that would encompass both stars.
But there are huge challenges to be solved, including the essential ground based laser booster of the type called for. Just solving those problems could deliver industrial technologies far more valuable to the inhabitants of late 21st century planet Earth than the early messages from a rapid fly-through of Alpha Centauri.