☄ Encke 2P/Encke

How to follow comet Encke live

The panel above recomputes the position of Encke 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 Encke 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 Encke with no math at all.

Comet fact sheet

About Encke

Comet 2P/Encke holds the title of periodic comet with the shortest known orbital period: approximately 3.3 years. That means it orbits the Sun almost six times more often than Halley, completing numerous laps while other famous comets are still far from perihelion. Originally discovered in 1786, it was the second comet to have its periodicity recognized - after Halley - and the first whose short period (under 10 years) was firmly established. Encke is also the most likely parent body of the Taurid meteor showers, which light up the skies from October through December with slow meteors and spectacular fireballs.

Decades of study have revealed an intriguing orbital anomaly: Encke's period decreases slightly with each pass, one of the first historical examples of non-gravitational forces recognized in cometary orbits. The comet is also notoriously spent - at only 4.8 km across, it has lost most of its surface volatiles over hundreds of perihelion passages.

History and discovery

Pierre Mechain first observed the comet on January 17, 1786, but did not track it long enough to determine its full orbit. Caroline Herschel independently rediscovered the same object in 1795, and Jean-Louis Pons spotted it again in 1805 and 1818. It was Johann Franz Encke who, in 1819, calculated the orbits of the 1786, 1795, 1805 and 1818 comets and demonstrated they were all the same object with a period of just 3.3 years. Encke correctly predicted the 1822 return, confirmed by Karl Ludwig Harding. The comet was named after Encke at Caroline Herschel's suggestion - one of the rare instances in astronomical history where a comet is named for the orbit calculator rather than the discoverer.

Since its recognition as a periodic object, Encke has accumulated the highest number of observed perihelion passages of any comet: more than 65 recorded passages through 2026.

Orbit and returns

Encke's orbit is a relatively compact ellipse, with perihelion inside Mercury's orbit (approximately 0.33 AU from the Sun) and aphelion just beyond Jupiter's orbit (roughly 4.1 AU). Its 3.3-year period is the shortest of any catalogued comet. Orbital inclination is only 11.8 degrees to the ecliptic plane, making its orbit relatively close to the solar system's median plane compared with other comets.

Notably, Encke's period decreases slightly with each orbit - an anomaly attributed for decades to non-gravitational forces from gas and dust ejection (the rocket effect), though a 2022 study in the Monthly Notices of the Royal Astronomical Society proposes a more complex dynamical history, possibly involving fragmentation of a larger comet.

The comet passes perihelion roughly every 1,200 days. In recent returns its peak naked-eye magnitude rarely exceeded magnitude 6, making it better suited to binoculars or amateur telescopes. The 2003 return was one of the most favorable of the modern era, with the comet reaching magnitude 4.5. The next perihelion is forecast for 2027.

Nucleus, coma and tail

Encke's nucleus is small and relatively inactive given its long history: estimated at about 4.8 km in diameter (some sources cite 2.4 km due to measurement uncertainty). Density is estimated at around 0.6 g/cm³ - less dense than water, consistent with a porous "rubble pile" of frozen material. The nucleus's low activity compared with younger comets is a sign that repeated close solar passages have depleted much of its surface volatiles.

Encke's coma near perihelion is typically compact, extending tens of thousands of kilometers. Unlike more active younger comets, Encke rarely develops a prominent dust tail, though an ion tail is observed near perihelion. The greenish color typical of active comets (from C2 and CN molecule emission) appears but with moderate intensity. The comet sheds measurable quantities of silicates and carbon on each return, feeding the debris stream of the Taurid complex.

How to observe

Because it returns every 3.3 years, Encke offers regular observing opportunities, but its typical magnitude near perihelion falls between 4 and 7, placing it at or below naked-eye visibility depending on local sky conditions. 7x50 or 10x50 binoculars are sufficient to detect the coma under dark skies. Amateur telescopes of 100 mm or more show coma detail and, in favorable perihelia, the beginning of a tail.

Encke's greatest public legacy is its role as parent body of the Taurids - a split shower with Southern Taurids (active September to November, peak around November 10) and Northern Taurids (active October to December, peak around November 12). The Taurids produce few meteors per hour (5 to 10 on average) but are famous for generating fireballs - brilliant bolides exceeding magnitude -5. The Taurid complex also includes the daytime Beta Taurids in June and July, detectable only by radar. In elevated-activity years such as 2005 and 2015, unusual fireball rates were recorded.

To observe Taurid fireballs, the best strategy is naked-eye observation in open fields on November 10 to 13 nights, after midnight when the radiant in Taurus is well up. All-sky cameras or surveillance cameras pointed skyward capture unexpected bolides throughout the night.

Missions and scientific associations

No spacecraft has visited Comet Encke close-up as of 2026, but the comet is a frequent target of both professional and amateur telescopes at every return. NASA's MESSENGER mission, during its 2011 Mercury flybys, indirectly detected effects of Taurid-complex particles (associated with Encke) on Mercury's exosphere, providing data on debris stream composition.

Scientific interest in Encke also centers on the Taurid complex. Researchers Victor Clube and Bill Napier proposed in the 1980s that Encke is just the most visible fragment of a giant comet that disintegrated tens of thousands of years ago - the "Quaternary Giant Comet" hypothesis. According to this model, periods of intense bombardment from fragments of that original comet may have influenced megafauna extinctions and climate shifts in the late Pleistocene. The hypothesis remains controversial, but ongoing research continues to identify new Taurid-complex members, including Earth-crossing asteroids such as 2004 TG10 and 2005 UR.

Trivia and records

• With more than 65 documented perihelion passages through 2026, Encke holds the record for the highest number of observed returns in astronomical history - no other comet comes close.
• Encke's anomalous orbital deceleration - the comet orbits slightly faster than pure gravity predicts - was one of the first historical examples of non-gravitational forces recognized in cometary orbits, decades before the concept was formally defined.
• The Taurid complex includes multiple Earth-crossing asteroids, supporting the hypothesis that Encke and these objects are all fragments of a far larger comet that broke apart tens of thousands of years ago.
• Caroline Herschel, who rediscovered the comet in 1795, was the first woman to discover a comet - a feat she repeated eight times total, making her one of the most prolific comet discoverers in history.
• A 3.3-year period means a 30-year-old observer can watch Encke return more than 15 times over a lifetime - more than any other catalogued comet.
• In October 2013, the MESSENGER probe recorded a notable increase in sodium and magnesium in Mercury's exosphere during a Taurid-complex meteor shower, confirming planetary bombardment by Encke-related debris.

Other comets

See the full comet catalogue.