From Lisa Grossman at ScienceNews:
Seven of those exoplanets are in the TRAPPIST-1 system, one of the most exciting families of planets astronomers have discovered to date. At least three TRAPPIST-1 planets might host liquid water on their surface, making them top spots to look for signs of life (SN: 12/23/17, p. 25).
Yet those planets shouldn’t exist. Astronomers calculated that the small star’s preplanet disk shouldn’t have contained enough rocky material to make even one Earth-sized orb, says astrophysicist Elisa Quintana of NASA’s Goddard Space Flight Center in Greenbelt, Md. Yet the disk whipped up seven.
TRAPPIST-1 is just one of the latest in a long line of rule breakers. Other systems host odd characters not seen in our solar system: super-Earths, mini-Neptunes, hot Jupiters and more. Many exoplanets must have had chaotic beginnings to exist where we find them.More.
NASA’s Transiting Exoplanet Survey Satellite (TESS) is expected to find thousands more exoplanets but the search for life on other planets is becoming more precise now. For example, SETI seeks to rebrand it goals, in pursuit of funding from the U.S. Congress. At this point, SETI might be on to something. It is now a search, specifically, for intelligent design – evidence of technology that could only arise through the application of intelligence to nature.
See also, for a look at earlier, less cautious approaches “Behold, countless Earths sail the galaxies … that is, if you would only believe …”
and
Don’t let Mars fool you. Those exoplanets teem with life!