Professor of Mathematics

Paata Ivanisvili

Department of Mathematics, University of California, Irvine

Candidate 27: Daedalia Planum lava plains

Strong · roughly 90%

Two CTX close-ups of the same 600 by 600 m of the Daedalia Planum lava plains, from August 2008 and June 2025, under the same sun. A dark spot at the arrow is present only in the 2025 image. — The same 600 × 600 m in August 2008 and June 2025, under the same sun. The arrow marks the new spot. NASA/JPL-Caltech/MSSS.

What changed. A dark spot about 40 m across, with a faint halo, appeared on the lava plains of Daedalia Planum between August 2008 and November 2018. It is still there in June 2025. An irregular dark spot 8.3 km to the south-east, seen only in the June 2025 image, is a separate and probably younger event; with a single image, it is not listed as a candidate.

Why it may be a new impact. Three images from 2007 and 2008 show nothing there; the last was taken under the same sun and lines up almost perfectly. The spot shows even through the haze left by the 2018 global dust storm, and six and a half years without change rule out a short-lived patch made by wind.

Location: 18.985° S, 223.656° E (136.344° W)
Absent: 24 November 2007, 21 December 2007 and 12 August 2008
Present: 30 November 2018 and 30 June 2025
Size: Dark spot about 40 m across, with a faint halo
Confidence: Strong candidate; roughly 90% that it is a new impact.
Caveat: It first shows in a 2018 image, so the camera teams may already have it on their unpublished lists; but it lies outside every footprint of the high-resolution HiRISE camera, and the teams normally photograph a new impact with HiRISE within months of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.

Five CTX images of the same 2 by 2 km patch of lava plains, from 2007 to 2025. A dark spot at the arrow is absent in 2007 and 2008 and present in 2018 and 2025. — All five CTX images of the same 2 × 2 km patch, 2007 to 2025. NASA/JPL-Caltech/MSSS.

A 12 by 12 km CTX view from June 2025 of the lava plains around the spot, with a dashed box around the 2 by 2 km patch and an arrow at the spot. — A 12 × 12 km view from June 2025. The dashed box is the 2 × 2 km patch. NASA/JPL-Caltech/MSSS.

The independent check: three columns of the same ground, 2 km wide above and 600 m wide below, with yellow ticks around the spot. The spot is missing in the earlier image, marked BEFORE, and present in the two later images, marked AFTER. — **Independent check.** A second, deliberately sceptical review downloaded every image again and found that the candidate passes every test. Each column is the same ground, north up, 2 km wide above and 600 m wide below. Columns marked BEFORE are earlier images in which the spot would have been visible had it been there; those marked AFTER show it. Each image keeps one contrast stretch in both rows, so the close-up cannot create a spot. NASA/JPL-Caltech/MSSS.