Overview

• The comet will pass about 18 million miles (29 million kilometers) from Mars on October 3, with ESA’s Mars Express and ExoMars Trace Gas Orbiter leading observations and NASA assets available to assist.
• 3I/ATLAS is traveling at roughly 193,000 mph (310,000 kph) and is only the third interstellar object ever confirmed in our solar system.
• Hubble data constrain the nucleus to between about 440 meters and 5.6 kilometers across, as ground-based images show a growing tail and broad coma.
• A new, not yet peer‑reviewed VLT/UVES analysis reports an unusual nickel‑to‑iron abundance in the comet’s gas, a finding researchers say needs further verification.
• Perihelion comes at the end of October, ESA’s JUICE will observe in November, and the comet’s closest Earth approach in December will still be a distant ~167 million miles.