Stargazing is not for everyone. For some of us the wonder of astronomy is what it can tell us about the nature of the universe. Iíve always been fascinated by the really big questions: Is there life anywhere other than on earth? How did our universe begin? What, if anything, existed before it? Are there other universes out there? Is our universe expanding, and how will it end?
As of now, about 358 extrasolar planets, or planets orbiting stars other than our sun, have been found. To be hospitable to life, an extrasolar planet would need to be rocky, rather than gaseous, and between half and twice the size of earth. It would also need to be orbiting within the habitable or ďGoldilocks Zone,Ē neither too close to its sun and thus too hot, nor too far and thus too cold, for water to exist in liquid form, on the presumption that liquid water is a requirement for life. Most exoplanets discovered so far are gas giants, or are orbiting outside the habitable zone, or have wildly erratic elliptical orbits hostile to life. This does not mean that planets hospitable to life are not out there, just that, with current technology, they are more difficult to discover. However, this is changing rapidly. Where we used to rely on observing the change in brightness created as a planet passes in front of its star, with improved technology, we can now observe some planets directly. This enables us to observe smaller planets, not just gas giants. On March 6, 2009, the Kepler mission was launched to search for earth-sized habitable planets within our region of the Milky Way, with initial results expected soon. Gliese 581 d, the fourth planet from the red dwarf star Gliese 581, twenty light years from earth, is currently our best bet for an exoplanet that could support life. It has been found to be within the habitable zone.
There are, however, other possibilities for extraterrestrial life closer to home in our own solar back yard. Jupiterís moon Europa appears to have an ocean of liquid water beneath its frozen surface, warmed by the interaction between Jupiterís gravity and that of Europa and other moons. Might there be life in such an ocean? Then thereís Saturnís moon, Enceladus, spewing water from geysers in its frozen surface. Might life exist there too? There is also evidence for Saturnís moon Titan as a contender, with its methane, its abundance of organic chemicals, and possibly a liquid water ocean beneath its icy surface. Closer to earth, Mars remains the most promising candidate for extraterrestrial life, with abundant evidence of liquid water in its past, and ice in its present, discovered by the Phoenix missionís Mars lander. Currently the lander is testing the Martian soil for organic chemicals.
For those who prefer more earthly pleasures, consider attending Arunah Hill Days at the Arunah Hill Natural Science Center in Cummington from August 21st to August 23rd. This free family-oriented weekend of astronomy will include stargazing, nature walks, rocket-building, launching and science education. On Saturday night guest speaker John Briggs, an expert on antique telescopes, will discuss his adventures researching and collecting important scientific instruments. For more information, visit www.arunah.org.
Amanda Jermyn, of Longmeadow, has been a member of the Springfield Stars Club since 2000 and currently serves on the club's board of directors. For more information, visit the Springfield Stars Club Web site at www.reflector.org or call 1(800)336-9054.
Copyright © Amanda Jermyn