Scientists have discovered a giant “extraterrestrial” comet hurtling toward the Sun.
The space sphere, measuring 6 km in diameter (known as 96P/Machholz 1), is believed to originate from somewhere beyond the Solar System and is being monitored by the Solar and Heliospheric Observatory (SOHO) of the European Space Agency (ESA) as it approaches Earth within the orbit of Mercury, leaving a trail of icy debris in its wake.
96P/Machholz 1 captured by NASA’s Galaxy Evolution Explorer (GALEX).
The comet’s tail primarily consists of gas, which streams out behind the ice and frozen gases as they are heated by the Sun’s radiation. In 2008, an analysis of material ejected by 150 comets indicated that 96P/Machholz 1 contains less than 1.5% of the expected amount of cyanogen and also has low carbon content—leading astronomers to conclude that it could be an interstellar object from another Solar System. Now, its approach toward the Sun may reveal even more secrets about it.
“96P is an atypical comet, both in composition and behavior, so we never know exactly what we might see. We hope to gain some fantastic scientific knowledge from this and share it with everyone as soon as possible,” said Karl Battams, an astrophysicist at the Naval Research Laboratory in Washington DC.
David Machholz first discovered the comet of the same name in 1986 using a homemade cardboard telescope. Most comets that fall toward the Sun tend to be smaller than 10 meters, and thus get burned up as they approach Earth.
However, the massive size of Machholz 1 (more than two-thirds the height of Mount Everest) seems to protect it from complete evaporation, and SOHO has detected this comet making five close passes around the Sun since its discovery.
Its closest approach to the Sun will occur on January 31 when it is near Earth at a distance of less than three times that of Mercury.
The comet may have found itself on its unusual orbit after being ejected from its original Solar System by the gravitational pull of a giant planet. After a considerable time wandering through space, a chance encounter with Jupiter may have bent its trajectory, capturing it around the Sun.
Other hypotheses suggest that this comet may not be an extraterrestrial object but could have formed in poorly understood regions of the Solar System or might have lost its cyanogen content as it repeatedly orbited the Sun.
SOHO has detected over 3,000 comets since its launch in December 1995, although its primary mission is to observe the Sun for violent outbursts known as coronal mass ejections, or solar flares that can trigger geomagnetic storms on Earth.
The strongest of these storms can disrupt the Earth’s magnetic field enough to cause satellites to fall to Earth, and scientists have warned that extremely powerful geomagnetic storms could even paralyze the Internet.
