← Back to dex
Epic pulsar 54 EP

J1921+1929

RA 290.3473° · Dec 19.4895° · pulsar

Loading sky survey…
🌌 View in 3D star map
Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 3 badges
54 pts · Epic
Epic 78 pts → Anomaly
  • Pulsar +22
  • Millisecond pulsar +20
  • Binary pulsar +12
Total score 54

24 more points to reach Anomaly.

Badges

  • Pulsar · +22
  • Millisecond pulsar · +20
  • Binary pulsar · +12

Trivia

Hard to believe

  • Surface speed. Its equator is moving at roughly 8% of the speed of light. Spin it much faster and it would tear itself apart.
  • Better than a clock. Millisecond pulsars keep time so well that a network of them is being used as a galaxy-sized detector for gravitational waves — more stable over decades than the best atomic clocks.

Handle with care

  • Its gravity. Surface gravity is around 190 billion times Earth's. A fall of one metre would end at roughly a tenth of the speed of light.

What it actually is

  • What it is. The collapsed core of a star that exploded: about one and a half Suns of matter crushed into a ball the size of a city, held up only by the refusal of neutrons to be squeezed further.
  • Reading the fog. Its dispersion measure is 64.8 — a count of the free electrons in every column of space between here and there. Those electrons slow the low-frequency pulses more than the high ones, and that lag is how its distance is worked out.
  • It has a partner. It orbits a companion star, and because its pulses are such a precise clock the orbit can be traced to extraordinary accuracy. A binary pulsar is how gravitational waves were first proven to be real, decades before one was directly detected.

Find it in the sky

  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around July — that's when to go looking.

Properties

binary
yes
bsurf
321724642.2
dm
64.7632
name
J1921+1929
period ms
2.6463

Nearby objects

About J1921+1929

J1921+1929 is an epic pulsar. It spins once every 2.646 ms, has a dispersion measure of 64.76 pc cm⁻³ and carries a surface magnetic field around 321,724,642 G.

The collapsed core of a star that exploded: about one and a half Suns of matter crushed into a ball the size of a city, held up only by the refusal of neutrons to be squeezed further.

How to see it

Like any astronomical target, J1921+1929 is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.

Why J1921+1929 is an epic pulsar

J1921+1929 scores 54 points on Spacedle's rarity scale, which places it in the epic tier. Another 24 points would lift it into a rarer tier.

That score comes from 3 science badges — Pulsar, Millisecond pulsar and Binary pulsar — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.