Euclid Survey Stumbles Upon Previously Unknown Comet

WHO:

CNET - The European Space Agency (ESA) and its Euclid telescope are involved in the discovery.

Mashable - ESA’s Euclid Space Telescope discovered comet C/2026 S1 (Euclid).

WHAT:

CNET - Euclid’s telescope imagery revealed a new comet by accident.

Mashable - The discovery was the Euclid Space Telescope’s first comet discovery.

Mashable - The comet is designated C/2026 S1 (Euclid).

WHERE:

Mashable - The comet was about 800 million miles from Earth.

HOW:

CNET - The comet was identified in Euclid telescope imagery using software designed to detect moving objects.

Mashable - The comet’s discovery interrupted a telescope survey.

(UPDATED October 21, 2026 22:27 UTC)

The European Space Agency’s Euclid space telescope has discovered a comet by accident, marking the mission’s first comet find. The object, designated C/2026 S1 (Euclid), was spotted in images gathered during a telescope survey. Software designed to detect moving objects helped identify the comet as it shifted across the imagery. The discovery interrupted the survey, which Euclid was carrying out for its broader scientific work. At the time it was detected, the comet was about 800 million miles from Earth. Euclid is designed to map the universe, but its observations can also capture unexpected objects moving through space. The find shows how imagery collected for one purpose can reveal other discoveries along the way. The European Space Agency has not said in these details what will happen next with the comet.