European astronomers have discovered a planet with about the mass of the Earth orbiting the second star in the Alpha Centauri system. It is the smallest exoplanet yet discovered around a star like the Sun. The planet was discovered using the 3.6-meter telescope at the European Southern Observatory’s La Silla Observatory in Chile.

The results are reported in a paper to be published in Nature. A copy of the paper can be found here.

The newly discovered planet orbits Alpha Centauri B once every  3.236 days, at a distance of only 0.04 AU (3.7 million miles). At that distance, there’s little chance of life. Surface temperature is estimated to be about 2,200° F.

Nevertheless, it is an encouraging sign for astronomers who are continuing the search for habitable planets around other stars. The fact that planets are now being discovered around the nearest stars is significant, since they will be the easiest to imaging with the next generation of high-technology space telescopes.

Assuming someone gets around to building those telescopes. NASA has not even launched an optical interferometry test mission. At the same time, however, NASA is spending $8+ billion on the James Webb Space Telescope, whose technology is fast becoming outdated. By the time it is launched, ground-based telescopes will be producing images with resolutions six times better than JWST, for a fraction of the cost.

Meanwhile, Dr. Sara Seager’s group at MIT is building the ExoplanetSat, a $5 million CubeSat that can take over some of the work now being done by the Kepler space telescope, which is in trouble. One of Kepler’s momentum wheels has failed. If another momentum wheel fails, the Kepler mission is finished. ExoplanetSat is designed to work in swarms. Given the satellite’s low cost, why isn’t NASA building hundreds of ExoplanetSats?

In a rational world, announcements like this would encourage space agencies to shift more of their limited budgets into related projects like Terrestrial Planet Finder and the 100 Year Starship Initiative. JWST is designed to answer interesting questions about our past – the early history of the universe, immediately following the Big Bang. Exobiology and exoplanet research will also tell us much about the past history of the universe, but they may also shed some light on our future by discovered worlds that may someday be new homes for man. It’s hard to understand why that is not given higher priority.

Written by Astro1 on October 16th, 2012 , Astronomy, Space Policy and Management

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