In a delightful alignment of astronomy and mathematics, scientists at MIT and elsewhere have discovered a “pi Earth” — an Earth-sized planet that zips around its star every 3.14 days, in an orbit reminiscent of the universal mathematics constant. The researchers discovered signals of the planet in data taken in 2017 by the NASA Kepler Space Telescope’s K2 mission. By zeroing in on the system earlier this year with SPECULOOS, a network of ground-based telescopes, the team confirmed that the signals were of a planet orbiting its star. And indeed,…