Freezing Cold Cryovolcano Erupts From Comet

A comet soaring through the darkness of space has been spotted exploding with activity. A cryovolcano housed in the comet has been erupting cold materials as opposed to volcanoes on Earth that spew hot lava.

Comet 29P/Schwassmann-Wachmann, the erupting comet in question, has often been observed suddenly spewing its gaseous innards into the vacuum of space from its cryovolcanoes, with 143 outbursts comprising 47 strong events and 97 mini-outbursts having been documented since mid-June 2017 by the British Astronomical Association.

This eruption in particular, which occurred on April 2, was unique, as astronomers managed to predict it before it happened.

The 29P/Schwassmann-Wachmann, measuring around 37 miles wide, takes roughly 15 years to orbit the sun and is one of around 500 "centaur" comets that moved from the Kuiper Belt of comets on the solar system's outskirts to an orbit between Neptune and Jupiter, per NASA.

Cryovolcanoes, similar to regular volcanoes, emit materials from within the interior of a planet or comet. However, cryovolcanoes release volatiles such as water, ammonia, or methane into environments below these materials' freezing points. When these cryovolcanoes erupt on comets, they send plumes of icy gas vapor soaring out into space, increasing the observed size and brightness of the comet by several folds.

On 29P, cryomagma consisting of cold liquid hydrocarbons, carbon monoxide, and nitrogen gas has been recorded flying outwards at speeds of 450 miles per hour, resulting in 10 times more light being reflected from the comet and therefore it appearing much brighter in the sky.

Cryovolcanoes have also been observed on Saturn's moon Enceladus, Jupiter's moon Europa and Neptune's moon Triton, as well as the dwarf planet Ceres in the asteroid belt, and Pluto.

Astronomers were able to predict Comet 29P/Schwassmann-Wachmann's eruption on April 2 as a result of the comet getting dimmer than usual, leading them to anticipate an eruption from the comet imminently.

"We have been watching 29P especially closely because [on April 1st] the pseudo-nucleus became very faint, indicative of the crust sealing and preventing outgassing," BAA's Richard Miles wrote in a blog post. "It was the faintest we had ever seen it."

"Recently, 29P has been behaving in almost a clockwork fashion—as the inner coma fades, it seems to reach a limiting brightness such that another outburst takes place within just a day or two."

In the post, Miles described how after an eruption, the vent appears to shut and seal rapidly, with there being no activity between eruptions.

"One interpretation of this behavior is that the crust is consolidated and that the rate that gas is forming beneath it is greater than the leakage rate through porous regions within it. So pressure builds up beneath the crust," the scientist wrote.

This then leads to a period of lower brightness due to less gas seeping into space, followed by an eruption as the pressure gets too high.

The 29P comet can still be seen glowing in the night sky as a result of its ejected materials and can be spotted using a telescope in the constellation Gemini.

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