Related: Don’t Panic! 3I\/ATLAS Isn’t an Alien Death Probe, But It Is Wildly Unusual<\/a><\/p>\n Since its discovery on 1 July 2025, 3I\/ATLAS has proven to be one of the most peculiar comets<\/a> humanity has ever seen. As it draws closer, first to the Sun and Mars<\/a>, now to Earth, its strangeness only intensifies.<\/p>\n Measurements of its coma \u2013 the ‘atmosphere’ of gas and dust surrounding an active comet \u2013 revealed an unusually early outgassing<\/a> producing large amounts of carbon dioxide<\/a>. Continued observations also showed huge amounts of hydrogen cyanide (HCN) and methanol (CH3OH)<\/a> appear in the coma as the growing warmth of the Sun caused the comet’s ices to sublime.<\/p>\n In the first two months following its discovery, researchers also noted strangely high amounts of nickel and iron<\/a>, noting a “potentially extreme composition” unlike any other comet.<\/p>\n In early October, 3I\/ATLAS came within a cosmic whisker of Mars; the encounter was recorded by Martian and solar observatories<\/a>. Observations of the comet became highly limited when its trajectory took it behind the Sun from Earth’s point of view during a crucial part of its travels \u2013 perihelion, the closest approach to the Sun, which took place on October 29.<\/p>\n When the comet emerged from behind the Sun’s glare, Earth observatories once again turned their gaze its way.<\/p>\n XMM-Newton<\/a>, an ESA X-ray observatory in Earth orbit, spent 20 hours gazing at 3I\/ATLAS, recording the glow of X-radiation<\/a> as the charged solar wind slammed into the ballooning coma. XMM-Newton is sensitive to soft X-ray emission from ions like carbon, nitrogen, and oxygen produced when the solar wind collides with neutral gases in the coma.<\/p>\n In late November, NOIRLab’s Gemini North telescope obtained observations of the comet that showed a hint of green<\/a>. This is interesting because early images of 3I\/ATLAS showed a more reddish tint, consistent with organic compounds called tholins<\/a> dusting the comet’s surface.<\/p>\n The greenish hue seen in many comets is generated by diatomic carbon (C2), which releases a green fluorescent glow when excited by solar radiation. However, pre-perihelion observations of 3I\/ATLAS suggested that it was unusually low in C2<\/a>.<\/p>\n C2 isn’t usually part of the composition of cometary ice, but forms<\/a> \u2013 and breaks apart<\/a> \u2013 quickly therein from free-floating carbon atoms from other carbon-containing molecules that break apart under solar radiation.<\/p>\n The new images suggest that 3I\/ATLAS only started forming C2 late in its journey through the Solar System \u2013 another of the comet’s odd behaviors.<\/p>\n We don’t know what all this means yet. Some scientists think that 3I\/ATLAS could be an unusually metal-rich object bristling with cryovolcanoes<\/a> that are sputtering its gases out into space. Another analysis suggests that the comet could be running out of ice<\/a>, transitioning into life as a post-cometary asteroid<\/a>.<\/p>\n In spite of all its oddities, everything it does points to it being a comet. The next critical flurry of observations will hopefully reveal more about the ways 3I\/ATLAS differs from our home-grown Solar System comets. Ensuing analysis from scientists may then yield insights into the strange environment of interstellar space.<\/p>\n![\"YouTube](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2025\/09\/1757406486_338_0.jpg\")
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XMM-Newton image of 3I\/ATLAS obtained on December 3. The red hue indicates X-radiation. (ESA\/XMM-Newton\/C. Lisse, S. Cabot & the XMM ISO Team<\/a>)<\/p>\n![\"Subscribe](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2025\/11\/Generic-Health-Promo-Final-642x273.jpg\")
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