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Amid renewed online speculation about a \u201cmysterious object hiding behind the Sun\u201d, astronomers confirm that interstellar comet 3I\/ATLAS remains under active observation. The object, formally designated C\/2025 N1 (ATLAS), was discovered on July 1, 2025 by the Asteroid Terrestrial-impact Last Alert System (ATLAS). It is approaching its perihelion, its closest point to the Sun, around October 29\u201330, 2025.<\/p>\n
Some media coverage amplified a hypothesis from Harvard astronomer Avi Loeb, suggesting that 3I\/ATLAS could be an artificial probe using the Sun to conceal its trajectory from Earth. However, astronomers monitoring the object emphasize that it remains visible to space-based instruments even during conjunction.<\/p>\n
One such instrument is the CCOR-1 coronagraph aboard NOAA\u2019s GOES-19 satellite, which observes the solar corona. CCOR-1 imagery has revealed a faint but detectable trace of 3I\/ATLAS. Thai amateur astronomer Worachate Boonplod first identified the comet in CCOR-1 data, matching its expected position and confirming its detectability in near-Sun conditions.<\/p>\n
NASA\u2019s Polarimeter to Unify the Corona and Heliosphere (PUNCH) spacecraft and coronagraphs aboard the Solar and Heliospheric Observatory (SOHO) have also been following the comet during its conjunction. Coronagraph specialist Karl Battams explains the challenge:<\/p>\n
\u201cObjects at the threshold of detection like 3I\/ATLAS are a challenge for coronagraphs. We often have to employ image stacking techniques. For this to work, we need a precise understanding of the telescope\u2019s pointing and distortion so that we can find the exact pixels corresponding to the comet. It gets fiddly, but we make it work.\u201d<\/p>\n
Battams adds that unless the comet fades substantially, it should remain observable through perihelion.<\/p>\n
A light curve assembled by T. Marshall Eubanks of Space Initiatives Inc, combining CCOR-1 and PUNCH data, indicates that 3I\/ATLAS follows a standard brightness pattern for outgassing comets, consistent with activity driven by gas and dust sublimation. No anomalous changes in direction or luminosity have been reported.<\/p>\n
Spectroscopic data from the James Webb Space Telescope and ultraviolet imaging from the Neil Gehrels Swift Observatory show that 3I\/ATLAS is composed mainly of carbon dioxide and water vapor. JWST measurements reveal a CO2<\/sub>\/H2<\/sub>O mixing ratio of about 8 \u00b1 1, while Swift data detected OH, a proxy for H\u2082O sublimation, indicating a water production rate near 1.3 \u00d7 1027<\/sup> molecules s-1<\/sup> (around 40 kg s-1<\/sup>). The Hubble Space Telescope has imaged the comet\u2019s faint coma and dust tail.<\/p>\n In December 2025, 3I\/ATLAS will emerge from the Sun\u2019s glare, allowing ground-based telescopes to resume direct observation. Predictions suggest it will remain faint, beyond naked-eye visibility, but within reach of professional and advanced amateur instruments.<\/p>\n While discussion about its nature continues in popular media, the balance of observational evidence strongly supports a natural origin. If 3I\/ATLAS were a spacecraft, it would be one that behaves exactly like a comet.<\/p>\n References: <\/p>\n