距太阳仅39光年外有7颗类似地球大小的行星，它们正围绕一颗质量只有太阳质量8%的恒星运转。这些行星的轨 道和木星的4颗伽利略卫星的轨道差不多大，围绕恒星转动的周期只有一天半到十二多天。它们都很可能是石质行星， 有可能存在液态水和大气，其表面至少有部分区域具有宜居条件。更多这样的行星正在被发现，它们和上述行星在韦布 太空望远镜发射并投入科学观测运行后，将成为其优先观测目标。那时，就可以对这些行星是否存在大气以及如果的确 存在大气的话对其大气成分得出结论，极有可能因此发现在某一颗或者几颗太阳系外的行星上确实有生物存在的迹象。

Just 39 lightyears from the sun, 7 earth-sized planets are orbiting a star whose mass is only about eight percent of that of the Sun. The orbits of these planets are only about as large as those of Jupiter’s Galilean moons, and the periods of orbiting around the star are only one and a half days to about twelve days. They are likely to be rocky planets, which may have liquid waters and atmospheres and have habitable conditions in at least some areas on their surfaces. More such planets are being found, which will be the preferred targets of scientific observations after the operation of the James Webb Space Telescope that will be launched. At that time, it is possible to draw the conclusions on whether these planets have atmospheres and what compositions the atmospheres made up of if they do exist. It is quite possible that we can find out life signatures on one or a few extrasolar planets.