Comet 29P explodes, blasting a 'fizzy cocktail' into space at 3218 km/hr

A comet discovered nearly a century ago is putting up a spectacular show in the night sky. Comet 29P/Schwassmann-Wachmann underwent an explosion in February 2026, which increased its brightness by several magnitudes. On the brightness meter, the cryovolcanic explosions have led it to jump from approximately magnitude 13.5 to 11.5. This event that unfolded within hours has increased its visibility. By February 13, its coma had expanded to about 45 inches, Bob King wrote on Sky and Telescope. He observed a "dense and impenetrable" core and a "very faint, stellar pseudo-nucleus." The comet will continue to become bigger over the next few days before fading again. King suggests getting a glimpse as soon as possible. Explosions aren't uncommon for comets. As they move nearer to the Sun, heat builds up inside the comet as volatile ices like carbon monoxide and carbon dioxide start vaporising. When the pressure becomes too intense, the material breaks through the crust in an explosion. This event increases their brightness.

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Fizzy cocktail brews and explodes from comet

The explosion in the case of Comet 29P was so massive that it sent debris flying into space at speeds of 3218 km/hr. The dynamic process will cause the comet's size and appearance to change almost every night. Richard Miles, director of the Asteroids & Remote Planets section of the British Astronomical Association (BAA), attributes it to a "fizzy cocktail" heating up inside the comet comprising liquid methane, ethane and propane, mixing with dissolved carbon dioxide. Astronomers expect the comet to undergo more explosions since something this big is typically followed by smaller ones. Comet 29P also witnessed two explosions in the year 2025.

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Slow rotation period of Comet 29P

Comet 29P is different from other comets in terms of distance from the sun and the corresponding activity. As opposed to comets that undergo cryovolcanism when they approach the Sun, 29P stays far away and yet undergoes such activity. It is a Centaur (an object between Jupiter and Neptune) that stays in a nearly circular orbit. It is one of the most active bodies in the solar system, thanks to its 57-day rotation period. This exposes parts of it to solar heat for several days, causing internal pressure to build up, which then releases.