Ultraconserved DNA sequences, unchanged in vertebrates for 300 million years, are maintained by selection four times as strong as that for coding genes.

Detection of gas around a type Ia supernova, a standard distance reference, implies that the progenitor white dwarf exploded after cannibalizing a red giant companion star.

The absorption spectrum of a quantum dot containing multiple atoms has the splitting characteristics and signature of a simple two-level system, as in a single atom.