All articles tagged with #sand dunes
An astronaut photograph from 2023 captures a trio of ancient black mesas in the Sahara, surrounded by unique sand dunes formed by wind patterns, remnants of a Paleozoic-era geological system possibly similar to the 'Eye of the Sahara'.
An astronaut photograph captures a large, slug-shaped sand dune field in Kazakhstan's Kazakh Steppe, which is gradually being stabilized by vegetation, potentially halting its movement due to plant growth, with future changes uncertain.
The Aorounga structure in the Sahara Desert, Chad, is an 8-mile-wide impact crater formed by a "city-killer" asteroid around 345 million years ago. Captured in a 2013 photo by an astronaut aboard the ISS, the crater's eye-like appearance is due to its two rings, with migrating sand dunes surrounding it. These dunes, known as barchan dunes, move significantly over time, as tracked by satellite images. The crater may be part of a "crater chain," with smaller craters nearby suggesting fragments of the original meteor impacted the area.
Residents of Salisbury Beach, Massachusetts, spent nearly $600,000 to have 15,000 tons of sand dropped near their beachfront homes to protect them from storms. However, a recent storm washed nearly half of the sand away, leaving the area defenseless against the ocean waters. The sand dune project was initiated after the beach was hit hard by storms in the past, and while the dunes sacrificed themselves to protect the properties, the community is now left feeling depressed, discouraged, and angry.
Machine learning has been used to analyze the morphology of barchan dunes on Mars, revealing the planet's atmospheric wind patterns. The study found that localized topography, such as impact craters, can deflect winds and influence dune formation. The research identified distinct patterns in dune migration related to summer atmospheric circulation, with northward-directed winds at mid-latitudes and cyclonic circulation near the north pole. At latitudes above 45°N, dune migration patterns are easterly, matching the cyclonic polar vortex circulation. The study provides valuable insights for understanding Mars' meteorological activities and supporting future manned missions to the planet.
China's Zhurong Mars rover has discovered evidence of a significant climate shift on Mars 400,000 years ago. The rover's investigation of sand dunes in Utopia Planitia revealed dark ridges called transverse aeolian ridges (TARs) formed on top of the dunes at a different angle than the wind-blown dunes. This discovery suggests a change in wind direction in the lower mid-latitudes coinciding with Mars' last major ice age. The ice age was caused by changes in Mars' rotational axis, resulting in climatic shifts. The findings provide insights into Mars' ancient climate and landscape evolution.
NASA has released a stunning 4K video showcasing the haunting beauty of the Matara Crater on Mars, captured by the HiRISE camera on the Mars Reconnaissance Orbiter. The video highlights the textured nature of the crater's dunes, which are sculpted by Mars' relentless winds. These dunes provide valuable insights into the planet's past and atmospheric conditions. While sand dunes are intriguing targets for exploration, they pose challenges for wheeled rovers. Scientists are developing rolling robots inspired by creatures like the Golden Wheel Spider to navigate these hazardous terrains.
NASA's Mars Reconnaissance Orbiter captured images of almost perfectly circular sand dunes on the Red Planet's northern hemisphere. While sand dunes of all shapes and sizes are common on Mars, circular dunes like these are a rare sight. The steep sides of the dunes are slanted southward, which might be due to Martian winds blowing the sand in that direction. However, scientists are unsure what caused the dunes to be so near-perfectly circular. The image is part of a series taken by HiRise to help monitor how frost melts on Mars at 60 different locations as the northern hemisphere of the planet reaches the end of its winter season.