Astronomers observed an object flying at approximately 26,000 mph (41,836 km/h) through our Solar System that stretches the definition of the word comet.
As astronomer Tony Phillips points out in an article for Spaceweather.com, "giant space volcano" might be the best way to describe the soaring rock, which is repeatedly erupting and spewing 'cryomagma' into space.
The 'giant space volcano' comet 29P erupts 20 times a year
The comet, called 29P, or Schwassmann-Wachmann 1, is essentially a colossal ice ball measuring 37 miles (60 kilometers) across, which is "festooned with ice volcanoes which erupt (around) 20 times a year," Phillips says. 29P was first discovered in 1927 on an orbital path between Saturn and Jupiter and its explosive nature has been known for decades. However, it is going through a particularly volatile period, with Arizona amateur astronomer Eliot Herman having observed the comet erupt four times in quick succession in late September.
"The current outburst, which began on Sept. 25th, appears to be the most energetic of the past 40 years," Dr. Richard Miles of the British Astronomical Association (BAA) told Spaceweather.com. "Within a span of only 56 hours, four eruptions took place in quick succession, creating a ‘superoutburst.'" According to Miles, who is a leading researcher on 29P, the comet is likely to contain no magma — at least not how we know it here on Earth. Instead, it contains 'cryomagma', a combination of cold liquid hydrocarbons, including methane and ethylene, similar to those present on the lakes of Saturn's moon Titan.
September eruptions made 29P 250 times brighter
Dr. Miles' model of 29P suggests that sections of the comet's surface have a consistency similar to wax. When a fissure opens on the surface, the dissolved gas forms of nitrogen and carbon monoxide burst out of the comet, leading to the eruptions that can be viewed from Earth. At least 6 volcano mouths have been identified on the comet to date. As Philips points out in his article, 29P is "one of the most volcanically active bodies in the entire Solar System."
What's more, the series of eruptions in September increased 29P's brightness 250-fold, and it is yet to decline to normal levels, meaning now is a great time for amateur astronomers to search for the space volcano in the sky. Space observation website Sky&Telescope has provided tips on how to find 29P in the night sky.
It's impressive to think that such a bizarre object — like something out of the highly-acclaimed fictional space simulator 'Outer Wilds' — is relatively close to Earth. According to SkyLive.com, 29P is approximately 434 million miles (700 million km) from Earth, which is relatively near in astronomical terms. As it's on a nearly circular orbit near that of Jupiter, there is no significant threat posed by 29P to Earth, meaning we're not about to witness the fever dream-like scenario of a massive volcano crashing through the sky, spewing 'cryomagma' as it goes.