Today is the 440th birth anniversary of Johannes Kepler, who along with Galileo ushered in the era of modern astronomy. His universal laws of planetary motion, known to every science student were published in March, 1609 in his book Astronomia Nova.
Appropriately, the ambitious Kepler space telescope was launched in March 2009, to closely study several hundred thousand stars for the presence of exoplanets. It has already monitored 160,000 stars (only a millionth of the galaxy’s stellar population) and even in its first few months discovered over 1,300 possible new worlds orbiting the distant stars.
Textbooks have to be overhauled as a far more exotic menagerie of exoplanets than astronomers ever expected were revealed. There are several candidates smaller than earth, 400 super earths (twice terrestrial diameter), 100 about earth size, more than 700 Neptune-size planets and a few hundred giants exceeding Jupiter in size.
Kepler is the first space mission in search of earth-like planets orbiting stars similar to the sun. Weighing more than a ton, the Kepler spacecraft carries a 55 inch telescope (largest launched beyond earth’s orbit!) and the largest camera ever sent in space, having more than 20,000 parts! The spacecraft is in a heliocentric orbit similar to that of earth in perfect synchrony with Kepler’s laws! Bill Borucki’s proposal for the spacecraft met with many obstacles and was finally launched 17 years after he made it.
Among the discoveries made by Kepler or confirmed are planets orbiting binary stars (like NN Serpentis), sixty stars hosting multiple planets including Kepler 11, where inner planets are denser (like our solar system) but five of the planets are packed into an orbit smaller than Mercury! The technology associated with the spacecraft including its very sensitive detectors and high-fidelity instruments, involved several thousand engineers working more than a million hours over five years!
