On Monday, NASA announced that its Kepler observatory has found 461 new planet candidates since the last Kepler catalog was released in February 2012, expanding the total number of planet candidates to 2,740 potential planets orbiting 2,036 stars. There was a disproportionate increase in the number of Earth-sized and super-Earth-sized candidates, indicating improvements in exoplanet detection methods.
In the past 48 hours, one candidate in particular has gained considerable media attention. The new exoplanet, tentatively named KOI (Kepler Object of Interest) 172.02, has 1.5 times the radius of Earth and takes 242 Earth days to orbit a star similar to our Sun at a distance of 0.75 AU. For comparison, Earth orbits the Sun in 365.256363 Earth days at a distance of 1.00 AU and Venus orbits the Sun in 224.698 Earth days at a distance of 0.723 AU.
Researchers from NASA note that KOI 172.02 would be a prime candidate to explore in the search for extraterrestrial life. However, life resembling humans might have a tough time on such a planet. The planet appears to be near the hot edge of the habitable zone, and may have temperatures that are too high for life as we know it to exist. It is also possible that KOI 172.02 is a heavy gravity world, as surface gravity increases linearly with radius if density is held constant. Therefore, if KOI 172.02 has a similar composition to Earth, it would have 1.5 times the surface gravity of Earth, which would be fatal to some lifeforms on Earth and quite uncomfortable for most animals. A different composition, like that of an iron planet, would raise the density and surface gravity even higher. Of course, extraterrestrial life need not be like us, so KOI 172.02 is still a place worth further study in the search for life in the cosmos.