The 2,500 Year-Old Search for Another Earth Continues


A 2011 graphic of the stars Kepler has identified as hosting planets; the potential planets are the dark spots, transiting their stars. For scale, the Sun is shown below the top row of stars towards the right. The dot is Jupiter. Credit: Jason Rowe/NASA Ames/SETI

NASA’s Kepler Space Telescope launched in 2009 with the express purpose of identifying exoplanets. A few weeks ago, it suffered a critical malfunction: the second of four reaction wheels that make up the spacecraft’s stability system failed, leaving Kepler unable to focus on its extrasolar targets. The public reaction was varied, some mourning the loss of the mission while others blamed NASA for launching imperfect hardware and called the mission a waste. What few seemed to focus on was how much this mission has changed how we think about the Universe around us. Kepler has found thousands of potential exoplanets – hundreds of which have been confirmed – giving us a Universe in which we are increasingly unlikely to be alone. This is a significant change of perspective. Thirty years ago, the idea of exoplanets was still a theory without proof. But it was an enduring, if unpopular, idea that dates back nearly 2,500 years. My latest article for Al Jazeera English gives an extremely brief overview of our millennia-old search for exoplanets and another Earth. (There’s a typo in the third paragraph. The last sentence should read: It was a cosmos that mimicked the perfection and simplicity of the divine mind, the view that had been propagated by Plato and picked up by Aristotle a century later.)

One Comment

  • stuyoung38 says:

    For those who criticize NASA for “imperfect hardware”…ridiculous!
    Consider the following, still-active, missions:
    Voyager 1, launched September 5, 1977.
    Voyager 2, launched August 20, 1977.
    MRO, launched August 12, 2005.
    Mars Odyssey, launched April 7, 2001.
    Stardust was launched on February 7, 1999. After completing its primary mission in 2006, it was extended to rendezvous with comet Tempel 1. It finally ceased operations in March 2011.
    Both MER rovers were launched in 2003, and were only expected to function for 90 sols. JPL finally lost contact with Spirit after 6 years 2 months 19 days, or over 25 times the original planned mission duration. Of course, Opportunity is still chugging along.
    Kepler was launched on March 7, 2009. It was expected to function for 3 yrs. 6 months. It made it, plus some change.
    Pretty damn good record, for an agency which (now) is only funded with 2/5 of 1% of the Federal budget!
    -Stu Young

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