Overview
- 3I/ATLAS will make its closest pass on Dec. 19 at roughly 167–170 million miles from Earth, and NASA says it poses no threat.
- More than 80 observers under the U.N.-backed IAWN are coordinating a worldwide campaign to refine the comet’s position and behavior, with about 100 participants at a mid-campaign briefing.
- Gemini North images from Nov. 26 show the coma shifting from red to green, which NOIRLab attributes to diatomic carbon emissions, and researchers say delayed heating could drive further outbursts.
- ESA’s XMM-Newton detected X-rays on Dec. 3 consistent with gas from the comet interacting with the solar wind, complementing Hubble and other missions and adding to reports of unusual CO2-to-water ratios and nickel vapor.
- A persistent sunward anti-tail has been documented since July and has appeared to vary in recent images; most teams explain it via dust and ice dynamics, while a minority “jet” hypothesis remains unsubstantiated by agencies.