67P/Churyumov–Gerasimenko
What is 67P/Churyumov–Gerasimenko?
Comets· Nucleus 4.3 × 4.1 km. The first comet humans ever orbited and landed on. ESA's Rosetta shadowed its rubber-duck-shaped nucleus for two years while it vented gas, and the Philae lander touched down. A short-period comet returning every 6.45 years — see its compact orbit inside Jupiter's in the orbit view.
The orbit of 67P/Churyumov–Gerasimenko at this moment: https://nowsky.org/solar/orbit?fw=c67p&sp=12 — replayed live, no login.
Orbit and period
| Nucleus | 4.3 × 4.1 km (duck-shaped, two lobes) |
|---|---|
| Period | 6.45 yr |
| Distance | 1.24~5.68 AU |
| Mission | Rosetta orbiter 2014–16, Philae lander |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Frequently asked
- How long is the orbital period of 67P/Churyumov–Gerasimenko?
- 6.45 yr.
- How far is 67P/Churyumov–Gerasimenko from Earth?
- 1.24~5.68 AU.
- In one line, what is 67P/Churyumov–Gerasimenko?
- Comets — The first comet humans ever orbited and landed on.
67P's water is not Earth's water
Rosetta's mass spectrometer measured the deuterium ratio in the water vapour 67P gives off, and found it more than three times that of Earth's oceans — one more piece of evidence against the old idea that Earth's water came from comets. At least Jupiter-family comets like 67P, it seems, were not the main suppliers of our seas.
Asteroids gained ground as the delivery candidate instead: the deuterium ratio in carbonaceous asteroids matches Earth's oceans well, and the Ryugu samples returned by Hayabusa2 reached the same conclusion. But values differ from comet to comet — Herschel's 2011 measurement of Comet Hartley 2 matched Earth — so the remaining question is not "comets or not" but "which comets". Rosetta also made the first detections of molecular oxygen and the amino acid glycine at a comet.
The comet in depth
Comet 67P/Churyumov–Gerasimenko was discovered in 1969 by Soviet astronomer Klim Churyumov on photographic plates taken by Svetlana Gerasimenko. A Jupiter-family short-period comet, it travels between 1.24 and 5.68 AU every 6.45 years; before a close pass by Jupiter in 1959 its perihelion lay at 2.7 AU and it was a far fainter object.
In August 2014, after a ten-year cruise, ESA's Rosetta entered orbit around the comet and revealed a nucleus of two joined lobes shaped like a rubber duck. That November the Philae lander touched down, but its harpoons failed to fire; it bounced twice and came to rest beneath a shaded cliff, returning data for 60 hours before its batteries died. Rosetta watched the comet flare to life as it neared the Sun and ended its mission in September 2016 by settling onto the surface. Along the way it detected molecular oxygen and the amino acid glycine.
Track 67P in the orbit view to see a small ellipse that dips inside Mars's orbit and reaches almost to Jupiter's. Its next perihelion comes in April 2028, when astronomers plan to compare the comet against Rosetta's maps.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.