winter
May 26, 2020
May 26, 2020 There are sand dunes near both the north and south poles of Mars. The ones I’m showing today are on the floor of Jeans crater, which is down at 69.5°S (for reference, on Earth, some bits of […]
August 21, 2019
Aug. 21, 2019 Trolling through the HiRISE image catalog, I came across some dunes that look a bit like bacteria. (Well okay, they look like some sort of microbe to my eye, which is highly untrained in looking at microbes, […]
August 28, 2018
Richardson crater is located at 72ºS, about 1000 km (~621 miles) from the south pole of Mars. It’s a moderately large crater, about 90 km (56) miles across, and it’s mostly filled by one of the biggest dune fields in […]
July 16, 2018
In many areas on Earth that get winter snow, spring thaw is a messy time. Frozen ground turns to mud, and there may be runoff everywhere from melting snow and spring rain. Or if you live in a place that […]
May 9, 2018
Here’s a grand dune, making its stately way northward under winds blowing mainly from the south-southeast (bottom to top), with a secondary wind blowing from the southwest (lower left to upper right). There are two rippled and sharp-crested slip faces […]
January 8, 2018
A Piece of Mars: The north polar dunes in this 575×325 m (0.36×0.2 mi) scene are made of dark sand covered by bright winter frost (which will soon sublimate away, as this image was taken in late spring). To the […]
September 5, 2017
A Piece of Mars: The sharp line in this 0.625×0.625 km (0.39×0.39 mi) scene is the crest of a long dune in Mars’ southern hemisphere. The sunlit side is also the lee side: the bright streaks are thin sand avalanches […]
February 21, 2017
A Piece of Mars: This is the crest of one of the largest dunes on Mars (0.5×0.5 km or 0.31×0.31 mi). The wind mostly blows from the right, slowly pushing sand up the windward slope. But frost accumulates on (and […]
September 19, 2016
A Piece of Mars: This 0.96×0.54 km (0.6×0.34 mi) late winter scene is a study in contrast. The dark top half is uniformly rippled. This is the shady surface of the main windward side of one of Mars’ biggest dunes, […]