The search for planets outside the solar system that could (repeat, could) harbor life goes on at a faster pace. The big gun is the Kepler Space Telescope, which in part was designed to look for terrestrial-like planets, and is now coming into the full stream of operation. Kepler scientists reported on Thursday (August 26, 2010) the first indication of a planet only 1.5 times the diameter of Earth in a solar system with a Sun-like star (now known as Kepler-9) about 2,000 light years away. The word ‘indication’ is important, since the planet and its characteristics are still in the confirmation stage. It would be the first Earth-size(ish) planet discovered by the Kepler team.

More definitely, the Kepler team announced the discovery of two Saturn-size planets in the same Kepler-9 solar system.

Kepler has already amassed about700 ‘candidate’ planets, with every expectation that there are many more to come.

Earlier in the week a European team working with the HARPS (High Accuracy Radial Velocity Planet Searcher) equipment at the European Southern Observatory in Chile reported discovery of an even smaller planet with a mass approximately 1.4 times that of Earth, orbiting a star (only) 127 light-years away. More spectacularly, this was just one of seven planets in a solar system, HD10180, located in the constellation Hydrus. Two of the planets, including the Earth-size(ish) planet still need confirmation, although there is a high probability of the finding.

With increasing sophistication in the instrumentation and analytical techniques, the number of exoplanets (planets outside our Solar System) is certain to grow rapidly. It’s obvious that there is no lack of supply. As one scientist put it (Douglas Lin quoted in the New York Times), “Planets are common, and their properties are diverse.”

The detection and analysis of the properties of the planets will eventually become the area of most improvement (and probably controversy). In many cases, determining the size, mass, orbit and order in the system is the easy part. Detection of atmosphere, geological makeup, and other physical properties will be based – at least for the time being – on equivocal data using methods of inference. At the moment, most of the exoplanets are automatically compared to those in our Solar System (Neptune-like, Saturn-like). Over time, it will become obvious that there are other categories of planets, some of which don’t fit descriptions in our solar neighborhood. Those and even odder planets will likely teach us the most about exoplanets.