Strong winds polished the snow of southwestern Alaska and stretched marine stratocumulus clouds into long, parallel streets in early January, 2012. After crossing Bristol Bay, the winds scraped the clouds across the tall volcanic peaks of the Aleutian Islands. As the wind impacted the immobile mountains, the airflow became turbulent, swirling in symmetric eddies and carving intricate patterns into the clouds on the leeward side of the islands. At the top of this image, the bright white color indicates a thick layer of snow overlying the land of southwestern Alaska. The pristine white is broken by the rugged Ahklun Mountain Range in the east, which is partially covered by a bank of clouds. Off the coast of Alaska, sea ice floats in Bristol Bay, cracked and chipped by the flow of the waters which lie underneath. A few cloud streets – parallel lines of clouds – can be seen in the far northwest over land. The clouds increase over the sea ice and become thick over open water, where row upon row of clouds lie close in perfectly parallel formation. The Aleutian Islands stretch from northeast to southwest across the image. Sea ice, which is bright white here, lies on the windward side of the islands. A few of the tallest volcanic peaks can be seen rising from the icy islands. The character of the cloud streets change as they impact the Aleutians, especially near the center of the image, where two rows of beautifully symmetric swirls of eddies in the clouds stretch across the sky. These swirling formations are known as von Karman vortex streets. This true-color image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite on January 11, 2012. Image Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team

A galaxy cluster located about 7.2 billion light years from Earth.
Credit: X-ray: NASA/CXC/Rutgers/J.Hughes et al, Optical: ESO/VLT/Pontificia Universidad. Catolica de Chile/L.Infante & SOAR (MSU/NOAO/UNC/CNPq-Brazil)/Rutgers/F.Menanteau, IR: NASA/JPL/Rutgers/F.Menanteau

The ridge captured in this HiRISE image is called a wrinkle ridge. This wrinkle ridge is located in Hesperia Planum, a region of over two million square kilometers (over 770,000 square miles) in the southern highlands of Mars. It is located northwest of the Hellas basin and adjacent to Tyrrhena Patera and contains abundant orthogonal and intersecting wrinkle ridges. Wrinkle ridges are long, winding topographic highs and are often characterized by a broad arch with superposed narrow asymmetric ridges. These features have also been identified on the Moon, Mercury, and Venus. Their origin is attributed to horizontal compression or shortening of the crust due to faulting and folding. They commonly have asymmetrical cross sectional profiles and an offset in elevation on either side of the ridge. Superposing or located on top of the wrinkle ridge, is a very fresh impact crater. We can tell that this crater is fresh because of its relatively sharp or crisp rim and unmodified shape. If you look closely, you can see faint rays of relatively fine material, boulders, and smaller secondary craters radiating from the crater and superposing the wrinkle ridge and older surrounding craters. Written by: Maria Banks   (25 January 2012)
Credits: NASA/JPL/University of Arizona

Powerful Cyclone Funso has spent the last week drenching Mozambique with flood-inducing rain as it slowly churned down the Mozambique Channel.
Credit: NASA Earth Observatory

Credit: NOAA Space Weather Prediction Center