Thanks to the Kepler Space Telescope, we know that our solar system isn’t the only neighborhood of planets in the galaxy. Astronomers have confirmed over 3,700 planets outside of our solar system, and thousands more are suspected. Two worlds, in particular, are surprisingly close to our own.
Celestial Neighbors
The nearest star system to our own is the Alpha Centauri system, in the constellation Centaurus. The red dwarf Proxima Centauri, the nearest star in the trio, is only 4.24 light-years away from Earth and has a single rocky satellite. Proxima Centauri b is Earth’s closest extrasolar cousin, though the likelihood of life existing on its surface is extremely slim. Proxima Centauri is a cool star with an explosive temper. Its outbursts of radiation have stripped the planet of any atmosphere it might have had.
While the planet does sit in the star’s habitable zone, astronomers say that the likelihood of life being able to survive on its surface is slim. The rocky world lies so close to Proxima Centauri, it is almost certainly tidally locked, meaning that the same side of the planet is always facing the star. This orientation leaves half of the planet cold and dark while the other half is perpetually sunny and exposed to stellar radiation.
A Better Gamble
Our next neighbor after the Alpha Centauri trio is the single-star system in the constellation Ophiuchus, Barnard’s Star. Since the 1960s, some astronomers have argued that there might be one or more gas giants in orbit around the red dwarf star, but it wasn’t until November of 2018 that scientists were able to gather enough evidence to support the claim.
Barnard’s Star b orbits its parent star at about 0.4 AU, which is about the same distance as Mercury’s orbit from our sun. Red dwarf stars are so much cooler than yellow dwarfs like our sun, Barnard’s Star b has no problem lying in such an intimate orbit. The planet is an icy super-Earth, with a mass just over three times that of our planet. It is situated in its star’s frost zone, where volatile compounds such as methane and water can condense and freeze solid. Barnard’s Star b is six light-years from us, and scientists hope to send a probe there before the end of this century.
Time For A Road Trip
Currently, covering any substantial amount of distance in space takes years, if not lifetimes. A drive that is now under development could propel small camera-bearing equipment through the void at roughly 12% the speed of light. Project Daedalus seeks to reach Barnard’s Star within 50 years of its launch by using nuclear pulse rockets, which boost the craft through a series of nuclear detonations. Once the vessel reached the star and its planet, it would study atmospheric composition and relay back data and photographs of the alien world.
Although it’s a stretch, another plan similar to Project Daedalus has been proposed. This long-term plan would be based around Jupiter and require the launch of a self-replicating probe, which would set up base around Barnard’s Star, where it would build a factory to produce exploratory probes and, eventually, another model of itself to go forth and explore the stars.
