Professor of Mathematics
Paata Ivanisvili
Department of Mathematics, University of California, Irvine
← Possible new impact sites on Mars
Candidate 34: Central Ulysses Fossae, Tharsis lava plains
Strong · roughly 90%
What changed. A compact, very dark spot about 45 m across appeared on smooth lava plains beside a graben (a long fault trough) in central Ulysses Fossae, between April 2010 and October 2022. It is unchanged in three later images, up to May 2025, on four orbits in all.
Why it may be a new impact. An April 2010 image, taken under the same sun as the May 2025 one, would have shown it clearly and shows nothing. Later images, with the sun in many directions, show the same spot, so it is not a shadow; it is on flat ground, not on the graben’s wall, so it is not a slope streak; and two and a half years without change argue against a short-lived patch made by wind.
- Location
- 11.992° N, 236.791° E (123.209° W)
- Absent
- 30 April 2010
- Present
- 9 October 2022, 2 December 2022, 20 March 2025 and 19 May 2025
- Size
- Compact, very dark spot about 45 m across
- Confidence
- Strong candidate; roughly 90% that it is a new impact.
- Caveat
- Only one earlier image exists, so the window is twelve years long. It first shows in a 2022 image, so the camera teams may already have it on their unpublished lists; but it lies outside every footprint of the high-resolution HiRISE camera, and the teams normally photograph a new impact with HiRISE within months of noticing it. Like every candidate here, it is unconfirmed: see the caveat.
