Overview

• Only the third known interstellar object, 3I/ATLAS is on an unbound hyperbolic trajectory and traveling at roughly 58–61 km/s through the inner solar system.
• Hubble observations reveal a coma with hints of a tail, and analyses constrain the nucleus to an estimated 320 meters to 5.6 kilometers in diameter.
• Forecasts indicate a closest approach of about 210 million kilometers from the Sun and roughly 270 million kilometers from Earth before the object exits the solar system.
• Most astronomers interpret the data as consistent with cometary activity, while Harvard’s Avi Loeb has publicized an unproven self‑emission hypothesis and floated speculative explanations.
• Loeb said the Mars Reconnaissance Orbiter’s HiRISE team responded favorably to his request for early‑October imaging, with broader telescope campaigns continuing ahead of perihelion.