Webb Finds Neptune-region Ice Clues in Interstellar Comet 3I/ATLAS

WHO:

Phys.org - A Southwest Research Institute–led study used NASA’s James Webb Space Telescope to examine interstellar comet 3I/ATLAS.

Phys.org - 3I/ATLAS is described as the third object from beyond the solar system ever identified.

WHAT:

Phys.org - The observations found ice grains streaming from 3I/ATLAS, consisting of tiny aggregates of water ice and dust.

Phys.org - The grains are about a micron or smaller.

Phys.org - The study’s findings link 3I/ATLAS’s ice signatures to worlds beyond Neptune.

Mashable - Webb found that interstellar comet 3I/ATLAS has “very dusty ice.”

Mashable - 3I/ATLAS’s ice matches ice on some freezing worlds beyond Neptune.

WHERE:

Phys.org - The study compares 3I/ATLAS’s ice signatures with those of worlds beyond Neptune.

Mashable - The comparison concerns freezing worlds beyond Neptune.

HOW:

Phys.org - Researchers used NASA’s James Webb Space Telescope to examine ice grains streaming from 3I/ATLAS.

Mashable - Webb’s observations identified the comet’s ice as very dusty and similar to ice on some worlds beyond Neptune.

(UPDATED October 27, 2026 15:06 UTC)

NASA’s James Webb Space Telescope found that interstellar comet 3I/ATLAS is streaming tiny, dusty grains of water ice into space. The grains are about a micron or smaller and contain aggregates of ice and dust. Their ice signatures resemble those on some frozen worlds beyond Neptune.