The interstellar object 31/ATLAS continues to puzzle astronomers, as a newly identified anti-tail anomaly raises fresh questions about its physical nature and possible origins. According to Harvard University astronomer Avi Loeb, the unusual glow of the sunward-facing jet of 31/ATLAS is dominated by particles far larger than those typically seen in ordinary comets.
These findings challenge long-standing assumptions about how cometary dust behaves.
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Anomalous Particle Sizes in 31/ATLAS
In a recent post on his personal blog, Avi Loeb explained that 31/ATLAS is “characterized by an anomalous size of the particles that dominate the glow of its jet facing the Sun.” Unlike familiar comets, whose brightness is driven by tiny dust grains that efficiently scatter sunlight, the anti-tail of 31/ATLAS appears to be composed of much larger particles.
Loeb emphasized that this distinction is critical. “Strictly speaking,” he wrote, “the anti-tail structure of 31/ATLAS is dominated by particles larger than typical dust grains, which are usually the most efficient at scattering sunlight.” This alone sets the object apart from nearly every comet previously observed within our own solar system.
