No, it’s *not* the smallest exoplanet found!

The web has been buzzing over what everyone is calling the smallest extrasolar planet found, weighing in at about 5 times the mass of the Earth. Problem is, that's not the smallest exoplanet found, not by a long shot. That record is still held by three planets massing 0.02, 3.9, and 4.3 times the Earth's mass, orbiting the pulsar PSR B1257+12. This newly found planet, orbiting the red dwarf GJ436, is the smallest yet found orbiting a Sun-like star. I'm not picking nits here. I'm trying to be careful. The news tends to focus on planets found orbiting stars like the Sun (that is, fusing hydrogen in their cores as the Sun does) because those planets are the ones in environments most like ours. Certainly, those ones resonate with us, because one of the goals of this search is to find not only a planet with roughly the same mass ...