JimBowie1958
Old Fogey
- Sep 25, 2011
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Two new Earths and the search for life - CNN.com
OK, orbitting their star in such a short time makes me wonder how the astronomers know that this is a case of only two planets? I am guessing that the star 'blinks' are adequately timed with a two star orbit, but is it possible that this might also be 4 or more stars that have so far happened to be at longer intervals that are offset so that there appears to be one or two orbits when there are three or four or more?
How do we know that there arent twelve planets there with what appear to us as 36 and 120 day orbits?
These planets, named Kepler 20-e and Kepler 20-f, have sizes and masses similar to the Earth, and their host star is similar to our sun. But the resemblance ends there. Both orbit very rapidly -- in 6.1 days and 19.6 days, respectively, compared to 365 days for an Earth year -- so both are much closer to their star than the Earth is to the sun.
OK, orbitting their star in such a short time makes me wonder how the astronomers know that this is a case of only two planets? I am guessing that the star 'blinks' are adequately timed with a two star orbit, but is it possible that this might also be 4 or more stars that have so far happened to be at longer intervals that are offset so that there appears to be one or two orbits when there are three or four or more?
How do we know that there arent twelve planets there with what appear to us as 36 and 120 day orbits?