During the past few years the existence of more than a hundred planets in orbit around stars within 170 light years of our own solar system have been confirmed by scientists. By measuring the “wobble” of such stars they can conclusively document the presence of giant gaseous planets similar in size to Jupiter or Saturn (or larger). But the present technology has heretofore been incapable of detecting smaller earth-sized planets. Two intriguing recent developments have made this topic even more intriguing and whetted scientists appetites for an early launch of NASA’s search for terrestrial planets.

The first is confirmation by two teams working to discover planets at much greater distance than the “wobble” technique permits, by using “microlensing,” which occurs when one star passes directly in front of another from the vantage point of earth. If the foreground star has planets in orbit they generate telltale “blips” in the brightness of the background star. The two teams have independently documented the existence of a planet about one and a half times the size of Jupiter in the constellation Sagittarius, orbiting a red dwarf star approximately 17,000 light years from earth.

In the second development, research performed by computer modeling of the hundred planetary systems discovered suggests that as many as half are likely to include smaller terrestrial planets which could orbit in the so-called “Goldilocks” zone, that region about the central star at which it is not too hot for liquid water and not too cold. These results are more optimistic than a study completed last year which concluded that perhaps at most a quarter of such systems might contain terrestrial planets in the potentially habitable, life-breeding zone.

(New Scientist, BBC)
–From the April 2004 Austin Review KB