B1937+21
Millisecond pulsar
PSR B1937+21
The first millisecond pulsar: 642 turns a second, and for years the most precise clock known.
04 / 06
- Catalogue
- PSR B1937+21
- Type
- Millisecond pulsar
- We listen at
- 1400.000 MHz
- Period
- 1.5578 ms
- Distance
- ≈ 11,000 light-years
- Discovered
- 1982
- By
- Don Backer, Shri Kulkarni and colleagues, Arecibo
- Position
- 19h 39m 38.6s
+21° 34′ 59″ - From Stilledal
- Circumpolar. Best in the early evening.
A star heavier than the Sun, twenty kilometres across, turning 642 times a second. The surface at its equator moves at about a seventh of the speed of light.
It was spun up by a companion star it has since eaten. That is how most millisecond pulsars are made: old, slow pulsars fed until they whirl.
Played through a speaker it is simply a note. It has been holding that note, give or take a microsecond, for longer than there have been oceans on Earth.
{What it sounds like}
A thin, steady whine, close to the note E5.
{Headphones help. The sound is synthesized from the real period and profile.}
{Next station/} 05 / 06 · 1420.405 MHz