Hubble Detects Anti-Correlated Jet Flips On 3I/ATLAS Pointing To A Controlled Rotational System

These are not brief puffs or stochastic releases. The jets maintain shape and direction across time, suggesting fixed source regions on or near the nucleus. Their brightness reversal points to a system where geometry and rotation matter more than chance. The pattern also aligns with a previously observed ~16-hour brightness modulation—often described as a “heartbeat”—that hinted at rotation months earlier. The new data strengthens that interpretation.

Harvard astrophysicist Avi Loeb has outlined two natural explanations that frame the debate. In the first, the jets originate from opposite sides of the nucleus. As 3I/ATLAS rotates, one source becomes active while the other is shaded, with heat conducted through the body to trigger a nightside response. This is physically possible, but it requires unusually efficient thermal transport through the nucleus—far from a given for an interstellar object of uncertain composition.

The second explanation keeps both jets on the sun-facing side but assigns them different particle physics. Larger dust grains, once ejected, are less affected by radiation pressure and form a long, persistent anti-tail. Smaller particles or gas, however, are rapidly decelerated by solar radiation and the solar wind, turning back sooner and forming a shorter, secondary jet. As rotation changes the illumination angle, the relative contribution of each component shifts, producing the observed brightness flip.