Planets around a clock that is a dead star

A millisecond pulsar is a clock. Wolszczan has found PSR B1257+12. He and Frail time it with the 305-metre dish at Arecibo. The pulses arrive early, then late, then early, in a pattern that is not the pulsar spinning down. Two bodies, then three, tug the dead star.

Bell Burnell’s 1967 scruff has become a metronome precise enough to weigh worlds. No one expected planets here. The supernova that made the pulsar should have wrecked them. They are there anyway, or they formed after, from wreckage. That argument continues.

Pulsar planets are real and rare in the later census. 51 Pegasi b, in 1995, will be the first around a Sun-like star. This night is earlier, stranger, and still a planet detection. A world does not have to orbit a living sun.