Hi, I know next to nothing about astronomy, so maybe someone here can help me out with this. We regularly hear about how astronomers have spotted a new planet. Usually it's reported to be a very large gas giant, and apparently astronomers use the gravitational lensing phenomenon to find them. My question is, do we know whether or not smaller planets are orbiting the stars that are in the relative neighborhood of earth? I would assume that it would be easier to detect planets on a nearby star, so would we be more likely to spot a small planet if it was closer to us? Do we really know anything about the solar systems of the nearby planets?
The only planets we can detect at the moment are giant planets, perhaps jupiter sized or larger; they are usually detected by tiny wobbles in the motion of the star as it moves through the galaxy, although some are detected by observation of irregularities in the dust clouds which surround the star, or by the variation in light from the star during a transit by the planet. It is not possible to detect Earth size planets yet, and it will not be possible until the new instruments and satellites are available, particularly Kepler, SIM, the Terrestrial Planet Finder and Darwin, all expected in the next decade or so... http://www.usatoday.com/tech/news/2003-06-03-planets-cover-usat_x.htm Nearby stars with planets are- Epsilon Eridani, with one planet larger than Jupiter (10 ly away) Gliese 876, with two planets bigger than Jupiter (15 ly away) 55 Cancri, with two (perhaps three) planets bigger than Jupiter (41 ly away) 47 Ursae Majoris 2 approx jupiter sized planets (45 ly away) and several more, further away... see http://www.extrasolar.net/star.asp?StarID=7 __________________ SF worldbuilding at http://www.orionsarm.com/main.html
