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Cryovolcanic "Devil comet" the size of a city erupts again as it heads in Earth's direction

A comet roughly the size of a city, informally dubbed the “Devil comet” due to its horn-like eruptions, is heading toward Earth and has exhibited a fascinating pattern of activity. 

Violent eruptions

Scientists have observed that this comet, officially known as Comet 12P/Pons-Brooks, undergoes violent ejections of ice and gas approximately every 15 days. 

The most recent eruption occurred on December 14, with the next anticipated around December 29 or 30.

Cosmic version of Old Faithful 

Astronomers have noted that Comet 12P completes a rotation every two weeks, which aligns its cryovolcanic vent with the sun, triggering eruptions due to intense solar heat. 

Richard Miles of the British Astronomical Association likened the comet to a cosmic version of the ‘Old Faithful’ geyser, with eruptions set off by sunrise at its location.

Cryovolcanic comets

Comet 12P/Pons-Brooks is characterized as a cryovolcanic comet, known for displaying volcanic-like activity. Unlike terrestrial volcanoes that eject molten rock, cryovolcanic comets release a mix of gasses and ice. 

As Comet 12P/Pons-Brooks approaches the sun, it heats up, causing a buildup of pressure in its nucleus. This pressure leads to explosive eruptions of nitrogen and carbon monoxide, ejecting icy debris through large cracks in its shell.

These eruptions can create unique visual patterns when viewed through a telescope, such as the devil horns, which have also been likened to a horseshoe or even the Millennium Falcon from Star Wars. 

Halley-type comet

The comet, comparable in size to the famous Halley’s comet, was last visible to the naked eye from Earth in 1954.

Referred to as a ‘Halley-type comet,’ 12P/Pons-Brooks shares a similar solar orbit class as the renowned Halley’s comet, with a 71-year orbit around the sun. While it will be closest to Earth in April 2024, it is expected to be visible to the naked eye in May and June 2024, peaking in brightness on June 2, 2024.

Historical significance 

The comet is named after two astronomers, Jean-Louis Pons and William Robert Brooks, who identified it in 1812 and 1883, respectively. They established that this devil comet revisits our solar system every 71 years. 

Significant outbursts have been recorded since the 19th century, with 2023 on track to match the number of outbursts typically observed over a year.

This intriguing comet offers a unique opportunity for astronomers and enthusiasts to witness a celestial phenomenon that combines historical significance with a spectacular display in our night sky.

More about cryovolcanic comets

Cryovolcanic comets, like 12P/Pons-Brooks discussed above, embody a unique phenomenon in our solar system. Unlike typical comets, primarily composed of ice, dust, and small rock particles, cryovolcanic comets harbor a remarkable feature: cryovolcanoes.

A cryovolcano, or an ice volcano, differs fundamentally from its terrestrial counterpart. Rather than spewing molten rock, these icy giants eject plumes of volatile substances like water, ammonia, or methane. 

These eruptions occur when the internal heat of the comet, often generated by radioactive decay or tidal interactions with a larger body, melts its subsurface ice. The pressure builds up until it finds a weak spot in the comet’s crust, leading to a spectacular outburst.

Remnants of our early solar system

The study of cryovolcanic comets provides invaluable insights into the early solar system. These comets are often considered pristine remnants from the era of planet formation, harboring materials that have remained largely unchanged for billions of years. 

Analyzing the composition of their ejecta can reveal secrets about the solar system’s infancy and the origin of water and organic compounds on Earth.

Significantly, cryovolcanic activity can dramatically alter a comet’s trajectory. As they eject material, they experience a reactive force, akin to a rocket’s thrust, which can change their orbit. This phenomenon makes predicting their paths more challenging, but also more exciting for astronomers.

Still much to learn about cryovolcanic comets

Furthermore, these comets serve as natural laboratories for studying extreme conditions. The interplay between their icy composition and the vacuum of space creates environments not replicable on Earth. 

Scientists believe that understanding these conditions could provide clues to extraterrestrial life and the adaptability of life in harsh environments.


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