In the Dec. 23 & Jan. 6 SN: Our top stories of 2017, grounded pterosaur hatchlings, protectors of the Dead Sea Scrolls, a counterintuitive metamaterial, neutron star sizing, arrow of time reversed, E. coli in flour and more.
SEVEN IN ONE GO The small, cool star TRAPPIST-1, illustrated here, hosts a bevy of Earth-sized planets. There could be many more stars like it worth studying.
STELLAR PETRI DISH The nurseries where stars are born, like Cepheus B (shown), are bathed in ultraviolet radiation. That radiation could make ice act like a liquid and help organic molecules form in space.
K. Getman et al/PSU/CXC/NASA (X-ray); J. Wang et al CfA/JPL-Caltech/NASA (IRL)
BLAZE OF GLORY Cassini burned up like a comet above Saturn’s cloud tops just before 5 a.m. PDT on September 15. This artist’s illustration shows what it may have looked like.