The European Space Agency's Euclid space telescope has discovered a previously unknown comet, now named C/2026 S1 (Euclid). Announced by ESA on 19 October 2026, it is the first new comet found by the mission.
The object appeared in images taken between 16 and 24 September 2026, during the Euclid Deep Field North survey. It was captured in five different fields of view, across 16 exposures. Moving-object detection software developed by Mikko Pöntinen of the University of Helsinki flagged an elongated streak — the first sign that it was not a distant star or galaxy.
Confirmation followed: a diffuse cloud of dust and gas, known as a coma, surrounded the nucleus, as expected for an active comet. No catalogue of known comets or asteroids matched the object, so the observations were reported to the International Astronomical Union's Minor Planet Center, which confirmed the discovery on 8 October 2026.
C/2026 S1 is about 1.3 billion kilometres from Earth, a distance comparable to the Sun's distance to the region between the orbits of Jupiter and Saturn. Unlike the planets, however, it does not lie in the same plane: its orbit arches high above the Solar System and should take thousands of years to complete.
The find is striking because comet hunting is not Euclid's job. The mission was designed to map billions of galaxies and investigate dark matter and dark energy, using deep, steady images. It also avoids the comet-rich band of sky along the Solar System's plane and usually visits each patch of sky only once, making a follow-up confirmation harder.
That is why ESA's team sees the discovery as a valuable test for the future: the fast path from detection to alert and confirmation shows how Euclid could help identify distant targets in time for missions such as Comet Interceptor. In this specific case, scientists say C/2026 S1 is not a suitable candidate for that mission — but the procedure itself is already an important result.
Image credit: ESA/Euclid/Euclid Consortium. The image combines eight exposures from Euclid's VIS camera, taken between 16 and 24 September 2026.
Sources: ESA — Euclid discovers new comet and Universe Today — The ESA's Euclid Space Telescope Has Discovered A New Comet.
Transparency: this article was produced with the assistance of artificial intelligence, cross-checking public sources on the internet, including ESA's official announcement. Please consult the original sources for full details.
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