The Pleiades star cluster, captured here in infrared by the Spitzer Space Telescope. Click on image to view slideshow. Credit: NASA/JPL-Caltech/J. Stauffer (SSC/Caltech).
The centuries of inquiry and knowledge that 2009’s International Year of Astronomy celebrates were not inspired by concerns over the ratio of spiral-to-elliptical galaxies, the behavior of supermassive black holes, the composition of the interstellar medium, or other interests of many modern astronomers. The driving force behind the development of astronomy was the question of humanity’s place in the universe, particularly whether or not other worlds exist outside our own, worlds like ours where sunlight-stirred wind, water, and earth somehow gave rise to flourishing life and intelligence.
It seems fitting, then, that this year — the 400th anniversary of both Galileo Galilei’s first use of a telescope and the publication of Johannes Kepler’s Astronomia Nova — the most anticipated astronomical event addresses precisely this question. The Kepler Mission, a space telescope named after the 17th-century pioneering astronomer and set to launch in March 2009, will likely bring us closer to knowing that answer than all other accumulated events thus far in human history.
Using a sophisticated photometer, Kepler will detect the shadows of planets as they travel across the faces of their home stars in their distant orbits. It may reveal and characterize hundreds of planetary systems, some of which could be like our own, complete with a “twin” of Earth. During its four-year mission in Earth-trailing orbit, the specially designed photometer will focus on and record data from a single swath of stars in our galaxy where stellar systems with habitable planets are likely to exist. The spacecraft will store the data and transmit to Earth about once a week. In years to come, the Kepler as well as other ambitious telescopes and observatories hold the promise of illuminating whether our situation here on Earth is an astounding rarity or an innumerably common occurrence.
