Euclid Telescope Spots Previously Unknown Comet
A University of Helsinki researcher's software flagged the object in Euclid images taken in late September 2026.
Updated on Nov. 3, 2026 in Space
The European Space Agency's Euclid telescope detected a previously unknown comet, designated C/2026 S1 (Euclid), in images taken between September 16 and 24, 2026. The International Astronomical Union's Minor Planet Center officially confirmed the discovery on October 8, 2026.
Why it matters
The find shows that Euclid, built to map distant galaxies, can also contribute to tracking comets and asteroids. It suggests its observations could help scientists identify candidates for ESA's future Comet Interceptor mission.
Euclid captured the object in five separate image sets, with the comet about 1.3 billion kilometers (808 million miles) from Earth. Its orbit takes thousands of years to complete, and the stub does not report its size or composition.
The players
Euclid
The European Space Agency's space telescope, designed primarily to map distant galaxies and probe dark energy.
Mikko Pöntinen
A University of Helsinki researcher who developed the software that detected the comet in Euclid's images.
Minor Planet Center
The International Astronomical Union's clearinghouse for reporting and cataloging small Solar System bodies such as comets and asteroids.
The details
Mikko Pöntinen, a University of Helsinki researcher, wrote software that flagged a fast-moving streak across several Euclid images. By predicting where the object would be, he located it in five image sets, showing a fuzzy cloud consistent with cometary activity, and reported it to the Minor Planet Center.
Timeline
September 16-24, 2026: Euclid captures images containing the comet.
October 8, 2026: The Minor Planet Center officially confirms the discovery.
The Big Picture
The discovery demonstrates that Euclid's wide-field survey data can be mined for comet candidates, a capability relevant to ESA's planned Comet Interceptor mission. It shows the observatory's archive may support Solar System science beyond its original cosmology goals.
Euclid's survey data could help astronomers find and assess comets, which may eventually inform future missions that visit them. For now, the find is a research result rather than a change to everyday life.
The takeaway
A telescope built to study galaxies has turned up a comet that no catalog had recorded, showing that survey data often holds more discoveries than its original purpose suggests. Researchers mining archives like Euclid's may find more objects in the years ahead.
Further reading
Explore more in Space coverage of telescopes and Solar System discoveries.
