Overview

• The object came within about 18 million miles (29 million kilometers) of Mars on Oct. 3, with ESA’s Mars Express and ExoMars Trace Gas Orbiter leading observations as NASA assets stand by to assist.
• Space agencies say it poses no threat to Earth, with the nearest Earth approach expected in December at roughly 167 million miles (269 million kilometers).
• Perihelion is forecast around Oct. 29–30 when ground-based views will be blocked by solar glare, and ESA’s JUICE spacecraft is scheduled to monitor the comet from Nov. 2–25.
• Hubble measurements constrain the nucleus to between about 440 meters and 5.6 kilometers across, and tracking places its speed near 193,000 mph (310,000 kph).
• A new, not-yet–peer-reviewed VLT/UVES analysis reports an unusual nickel-to-iron abundance in the coma, a puzzling finding that scientists are continuing to evaluate.