As the Arctic warms, methane that was previously trapped by permafrost rises from the muddy bottom of lakes to escape into the atmosphere. Here the first clear ice of the fall has trapped the rising methane bubbles, allowing scientists an opportunity to estimate the amount of methane being released. When spring arrives and the lakes melt, the methane will rise again. (Photo credit: M. Thiessen/National Geographic)
Jupiter is home to one of the most famous storms in the solar system, the Great Red Spot, which Earth observations place at a minimum of 180 (Earth) years in duration. Some evidence suggests that it may have been observed by humans as early as 1665. The magnitude of such a storm is almost unimaginable. At its narrowest point, the storm is still as wide as our entire planet and observations from the Voyager crafts indicate that the storm has 250 mph winds. The scale of mixing and turbulence around the storm, seen in photographs, is stunning and beautiful. (Photo credits: NASA/Voyager 1 and Michael Benson; submitted by oneheadtoanother)
This numerical simulation shows the variation of salinity in the Atlantic Ocean near the mouth of the Amazon River over the course of 36 months. The turbulent mixing of the fresh river water and salty ocean shifts with the ebb and flooding of the river. Salt content causes variations in ocean water density, which can strongly affect mixing and transport properties between different depths in the ocean due to buoyancy. Understanding this kind of flow helps predict climate forecasts, rain predictions, ice melting and much more. (Video credit: Mercator Ocean)
The winds of Mars create sand dunes that seem to flow like a liquid across the planet’s surface. Here the wind blows from right to left around the flat top mesas on the right side of the image. The dark, arc-shaped dunes formed in the wake of the mesas are called barchans and can move downstream remarkably intact, even able to cross paths with other dunes. (Photo credit: MRO, NASA; via APOD)
Magnifique vue de cristaux de calcite ! A priori, microscope électronique à balayage… Deux nucléus de type différents (la légende parle de nucléus d’origine organique) explique les deux structures très différentes. Sans doute un bon exemple de l’importance des conditions aux limites !
“In this image, one organic template produces the leafy structure in the top half of the image, while a second template induces the formation of a cube. “It looks like the bush is growing out of a cube,” says Joanna Aizenberg. Both are made of calcium carbonate. The structure resembles that of a mollusk shell—the outer part of the shell is made of calcite, like the cube in the bottom part of the image. The inner shell is made of aragonite, which has the same chemical formula as calcite but different properties, and resembles the leafy structure in the top of the image.”