Wednesday, October 17, 2012

Not Quite Wunderland

Wunderland is a planet circling Alpha Centauri, and was the earliest extra-solar colony in Known Space's human history. It has a surface gravity of 60% that of Earth's and is hospitable to human life. Wunderland was invaded and its population enslaved by the Kzinti during the first Man-Kzin War. It was freed near the end of the First War by the human Hyperdrive Armada from We Made It. (“Known Space: Locations” from Wikipedia, The Free Encyclopedia)

The Alpha Centauri (α Cen) System, consisting of the two stars α Cen A and α Cen B orbiting each other, is our Sun's closest1 neighbour in space. And because in space ‘close’ is still quite far away, and also because both of α Cen's component stars are conveniently very Sun-like, we should not be surprised that not only have many significant works throughout the history of science fiction2 featured planets orbiting one or both of its component stars, but that proponents of interstellar space exploration, too, have set their focus on α Cen as the most promising first target. Not only due to the Sun-like nature of its stars, but also because relying on propulsion technologies that are considered realistic for the foreseeable future, α Cen is the only target that a probe could reach and report back its results from in the time of a human lifespan; even though the resources required for such an enterprise means that economical limitations makes it unlikely that we will launch such a mission in the near future.

Therefore, yesterday's announcement by the European Southern Observatory (ESO) that it has found a planet orbiting α Cen B means a significant boost for such speculation. The planet, designated α Cen Bb orbits α Cen B at 0.04 au with a ‘year’ of only 3.236 days. α Cen B in turn orbits α Cen A in a highly elliptical orbit at a distance which is roughly the same as from the sun to Saturn and Neptune respectively. And even though α Cen B is slightly smaller and colder than our Sun, the small distance between it and the newly discovered planet means that the planet's surface will be hotter than Mercury and therefore certainly no target for even the most aspiring space colonialists.

However, its discovery confirms speculations that there at least is something for a theoretical interstellar probe to look at around any of α Cen's stars. Additionally, α Cen Bb is not only the nearest extrasolar planet discovered so far but with a mass of only 1.13 Earth masses also the smallest one in orbit around a solar analogue star. And while our technological capabilities are still to weak to detect any planets in orbits further out around either α Cen A or α Cen B, the discovery of α Cen Bb raises the possibility that they might exist. If they do, it will only be a matter of time before astronomers will learn of their existence.

For now, α Cen Bb might be only a rock, but it has the possibility to become a very important rock.

  1. Proxima Centauri is slightly closer (~0.24 ly) than either α Cen A or α Cen B. However, most astronomers assume that Proxima is part of the α Cen system, thereby making it a triple star system.
  2. Philip K. Dick's Clans of the Alphane Moon, The Man-Kzin Wars by Larry Niven (which features the planet Wunderland mentioned above) and Footfall by both Niven and Jerry Pournelle, The Songs of Distant Earth by Arthur C. Clarke, William Gibson's Neuromancer, The Killing Star by Charles R. Pellegrino and George Zebrowski, and, last but not least, Avatar, James Cameron's latest blockbuster—just to mention a few examples.

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