Pulsar (rarely referred to as Cambridge pulsar CP 48-56-72[note 1]) is a large but surprisingly common period-3 oscillator. It was found by John Conway in March 1970.
The rotor of a pulsar consists of four mutually stabilizing quadrants; alternate arrangements exist for any odd multiple of 4 (for the version with 12 copies, see quasar). A closely related oscillator — the pulsar quadrant — includes just the external "horns" of the rotor and can be stabilized on its own.
Despite its size, pulsar is the fourth most common oscillator (and the most common of period greater than 2) in Achim Flammenkamp's census; the only oscillators more common are blinker, toad, and beacon. It is by far the most common period 3 oscillator, being about 45,000 times more common than jam. Overall, the pulsar is the twenty-first most common object on Adam P. Goucher's Catagolue.
A pulsar-on-pentadecathlon is the largest object to have occurred in the B3/S23/C1 census as of September 2020, with 100 cells in its maximum phase.
- ↑ The numbers refer to the populations of the three phases. The Life pulsar was indeed discovered at Cambridge, like the first real pulsar a few years earlier.
- 48P3.6 at Heinrich Koenig's Game of Life Object Catalogs