Cygnus X-1
Position on the route: 172/181 · level needed 3400 · journey (Mk0 engine) 470.2 h
By the numbers
| Distance | ≈ 7,200 light-years |
|---|---|
| Black hole | ≈ 21 Suns |
| Companion | blue supergiant |
| Orbit | 5.6 days |
The story
Cygnus X-1 is a bright X-ray source in Cygnus about 7,200 light-years away. It was found with a rocket in 1964; by the 1970s it was understood to be a black hole of about 21 solar masses, circling its blue supergiant companion HDE 226868 every 5.6 days: the first object generally accepted as a black hole.
In 1974 Stephen Hawking bet Kip Thorne that Cygnus X-1 was not a black hole (as an ‘insurance policy’) and conceded in 1990. The black hole pulls gas from its companion, and the gas heats and glows in X-rays; its event horizon is some tens of kilometres across.
Missions
- Uhuru (NASA, 1970): X-rays
- Chandra, NuSTAR: detailed measurements
Colony note
No surface; a very distant, heavily shielded station.
☠ A black hole drawing gas from its companion: bright X-rays. Only a very distant, heavily shielded station.
What probes bring back
- One of the first strong X-ray sources spotted from a rocket (1964); by the 1970s it was understood to be a black hole of about 21 solar masses, around 7,200 light-years away.
- Stephen Hawking bet Kip Thorne in 1974 that it was not a black hole and conceded in 1990. It pulls gas from a blue supergiant companion, and the gas glows in X-rays as it heats.