← Back to dex
Uncommon pulsar 22 EP

J1921+0812

RA 290.4488° · Dec 8.2144° · pulsar

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

Computing the sky for your location…

Score breakdown

· 1 badge
22 pts · Uncommon
Uncommon 34 pts → Rare
  • Pulsar +22
Total score 22

12 more points to reach Rare.

Badges

  • Pulsar · +22

Trivia

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 84 — 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.

Find it in the sky

  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around July — that's when to go looking.

Standing on it

  • Why we can see it. We only know about it because its beam happens to sweep across the Earth. Most of the galaxy's pulsars are pointing somewhere else and are invisible to us.

By the numbers

  • Density. A sugar-cube of its core would weigh about a billion tonnes — as much as every car on Earth put together.
  • Spin. It whirls around 4.7 times every second, and it has kept that beat to better than a millionth of a second.

Properties

bsurf
1075584976000
dm
84
name
J1921+0812
period ms
210.6484

Nearby objects

About J1921+0812

J1921+0812 is an uncommon pulsar. It spins once every 210.648 ms, has a dispersion measure of 84 pc cm⁻³ and carries a surface magnetic field around 1.08×10^12 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+0812 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+0812 is an uncommon pulsar

J1921+0812 scores 22 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 12 points would lift it into a rarer tier.

That score comes from 1 science badge — 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.