☄ Churyumov-Gerasimenko 67P/Churyumov-Gerasimenko

How to follow comet Churyumov-Gerasimenko live

The panel above recomputes the position of Churyumov-Gerasimenko every second in your browser: its distance from the Sun and from Earth, its position in the sky (right ascension and declination), and a live countdown to the next perihelion. It runs on the same kind of engine observatories use, a Kepler solver applied to the JPL osculating orbital elements, so the numbers are not a static snapshot, they keep ticking.

Just below, the top-down map of the Solar System shows exactly where Churyumov-Gerasimenko is right now among the planets. You can fast-forward time with the day slider, zoom and pan, compare its distance to another body with a click, and press "Next event" to jump straight to perihelion. It is the most direct way to grasp the orbit of Churyumov-Gerasimenko with no math at all.

Comet fact sheet

About Churyumov-Gerasimenko

Comet 67P/Churyumov-Gerasimenko, discovered in September 1969 from photographic plates, became the most extensively studied cometary object in history thanks to ESA's Rosetta mission. From August 2014 to September 2016, the Rosetta spacecraft orbited 67P at distances ranging from a few kilometers to a few hundred kilometers, recording the evolution of its activity from the distant cold at 3.5 AU all the way to perihelion at 1.24 AU, while the Philae lander touched the surface in November 2014. The data collected revolutionized the understanding of cometary composition, internal structure, geology and chemistry.

The comet has an orbital period of 6.44 years and the next perihelion is predicted for November 2028. Its current orbit is the result of a 1959 Jupiter gravitational perturbation that brought the comet much closer to the Sun, transforming a practically inert object into a moderately active comet.

History and discovery

Klim Ivanovych Churyumov, a Ukrainian astronomer at the Kiev Astronomical Observatory, discovered the comet in September 1969 while examining photographic plates taken by Svetlana Ivanovna Gerasimenko during an observing expedition at the Alma-Ata Observatory (today Almaty, Kazakhstan). Churyumov initially identified what he thought was comet 32P/Comas Sola on one of the plates. On closer examination he noticed the object was displaced 1.8 degrees from the expected position of 32P - it was a different comet. The formal discovery was announced in October 1969.

The comet was selected as the Rosetta target after the original target (46P/Wirtanen) became unreachable due to an Ariane 5 rocket failure in December 2002. The target change required a complete trajectory revision, but 67P proved the right choice: its 6.44-year period and orbital geometry were well suited for an extended rendezvous.

Orbit and returns

67P/Churyumov-Gerasimenko orbits the Sun with a period of approximately 6.44 years. Perihelion lies about 1.24 AU from the Sun (slightly beyond Earth's orbit) and aphelion about 5.68 AU, near Jupiter's orbit. Orbital inclination is roughly 7.04 degrees relative to the ecliptic - one of the lowest among Jupiter-family comets.

The current orbit is the result of a Jupiter gravitational perturbation in February 1959 that reduced perihelion from 2.77 AU to 1.29 AU, dramatically increasing solar activity. An earlier perturbation in 1840 had already moved perihelion from 4.0 AU to 2.77 AU. Before 1840, the comet was probably completely inactive, with a frozen surface and no coma or tail formation. The last documented perihelion occurred in November 2021. The next is predicted for November 2028. In each return the comet can reach magnitude 10 to 13, accessible to medium-to-large amateur telescopes.

Nucleus, coma and tail

67P's nucleus has a distinctive bilobed shape - the "rubber duck" shape - with two lobes joined by a narrow neck. The larger lobe measures roughly 4.3 km by 4.1 km, and the smaller lobe 2.6 km by 2.3 km. Total mass is estimated at 9.982 x 10¹² kg - about 10 trillion tonnes - and average density at just 0.533 g/cm³, confirming a highly porous structure (approximately 70 to 80% empty space). The bilobed shape most likely resulted from a low-speed collision (a few meters per second) between two separate nuclei in the early solar system, though differential erosion is also considered.

67P's surface as revealed by Rosetta is geologically diverse: cliffs tens of meters tall, debris fields, flat regions covered by fine granular material, isolated boulders hundreds of meters across, and deep fractures. Rosetta identified and named 26 geomorphologically distinct regions on the surface. The active coma, observed over more than two years, showed gas and dust jets emerging from specific regions as the comet warmed, with activity peaking at the August 13, 2015 perihelion.

How to observe

67P/Churyumov-Gerasimenko is a faint comet, typically magnitude 10 to 13 in normal returns, requiring telescopes of at least 150 to 200 mm for visual detection under very dark skies. In particularly favorable returns it can reach magnitude 8 to 9. It is not a naked-eye object under normal conditions.

The next perihelion is predicted for November 2028. In that return, the observing geometry will determine the maximum brightness accessible to Earth-based observers. Dedicated amateur astronomers who observed it in 2021 reported visual detection with 200 mm telescopes under dark skies, the coma appearing as a diffuse haze without a sharp central condensation. For photography, cameras with CCD or CMOS sensors and 150 mm or larger telescopes on motorized equatorial mounts can capture the coma and, in some cases, the beginning of a tail in multi-minute exposures.

67P is not associated with any significant meteor shower observable from Earth. Although the comet deposits material in its orbital trail, the intersection of that trail with Earth's orbit is not geometrically favorable to generate an observable shower.

Rosetta mission and scientific discoveries

ESA's Rosetta mission launched on March 2, 2004, and traveled 10 years before reaching 67P in August 2014, completing four planetary flybys (Earth three times, Mars once) to build speed. Among the most notable discoveries:

• D/H ratio in water: the deuterium-to-hydrogen ratio in 67P's water is about three times higher than in Earth's ocean water, indicating Kuiper Belt comets like 67P were probably not the main source of water in Earth's oceans.
• Molecular oxygen: Rosetta detected O2 (molecular oxygen) in the coma - an extremely surprising finding, since O2 is chemically reactive and its presence suggests primordial entrapment in the solar nebula before planet formation 4.6 billion years ago.
• Organic compounds: more than 400 different organic compounds were detected in the coma, including glycine (an amino acid), phosphorus and other molecular building blocks of life - reinforcing the hypothesis that comets contributed to prebiotic chemistry on Earth.
• Molecular nitrogen: N2 was detected, allowing an estimate of the nucleus formation temperature below 30 K (-243 C), confirming origin in very cold regions of the protoplanetary disk.
• Cliff collapse: Rosetta documented a cliff collapse in the comet's neck region - the first landslide on a comet associated with an outburst of activity, demonstrating that the cometary surface is geologically and dynamically active.
• Rotation axis shift: 67P's rotation axis shifted during the perihelion passage due to torque from asymmetric gas emission - the comet physically reoriented itself as it warmed up.

The Philae lander touched the surface on November 12, 2014, but bounced twice because its anchoring harpoons failed to fire, coming to rest in a shadowed region where solar panels received insufficient light. Even so, it transmitted data for 60 hours before going to sleep, and was briefly reactivated in June and July 2015. Rosetta was concluded with a controlled landing on the comet surface on September 30, 2016.

Trivia and records

• Rosetta traveled 6.4 billion km over 10 years before reaching 67P - one of the most complex interplanetary trajectories ever executed, involving 4 planetary flybys and a 31-month hibernation period.
• Philae was the first human-made object to land on a comet surface. Before going to sleep, it transmitted data revealing the surface was harder than expected - with a rigid crust of a few centimeters covering softer material below.
• The nucleus density (0.533 g/cm³) is less than water and far less than rock - confirming the nucleus is approximately 70 to 80% empty space, an extremely porous "frozen rubble pile" structure.
• The lander's name "Philae" refers to the Philae Obelisk, which helped decipher Egyptian hieroglyphics - just as the Rosetta Stone (from which the mother probe takes its name) helped decode Egyptian writing. The decipherment theme was intentional.
• 67P is nicknamed the "rubber duck" by the astronomical community because of its distinctive bilobed shape. When Rosetta arrived, the unusual form surprised scientists, as most prior models assumed more spherical nuclei.
• The detection of more than 400 organic compounds in 67P's coma, including glycine (an amino acid), reignited debate about the panspermia hypothesis - the idea that molecular building blocks of life may have arrived on Earth carried by comets.
• Rosetta also carried a commemorative plaque bearing the names of more than 36,000 members of the general public who registered in the "Send Your Name to the Comet" program before the 2004 launch.

Other comets

See the full comet catalogue.