ESA dixit:
“Having detailed knowledge of the shape of the seafloor is essential for generating nautical charts for navigation. It is also needed for exploration, fishing, coastal management and for understanding ocean currents that transport heat, nutrients and pollutants. While mapping the seafloor was traditionally carried out using sonar on ships, optical satellite data provide global, high-resolution maps that show ridges, valleys and sediments.”
Video credit: ESA
NASA dixit:
“July 25, 2016. In the Shangri-La Sand Sea on Titan is shown in this image from the Synthetic Aperture radar (SAR) on NASA’s Cassini spacecraft. Hundreds of sand dunes are visible as dark lines snaking across the surface. These dunes display patterns of undulation and divergence around elevated mountains (which appear bright to the radar), thereby showing the direction of wind and sand transport on the surface. Sands being carried from left to right (west to east) cannot surmount the tallest obstacles; instead, they are directed through chutes and canyons between the tall features, evident in thin, blade-like, isolated dunes between bright some features. Once sands have passed around the obstacles, they resume their downwind course, at first collecting into small, patchy dunes and then organizing into larger, more pervasive linear forms, before being halted once again by obstacles.
These patterns reveal the effects not only of wind, perhaps even modern winds if the dunes are actively moving today, but also the effects of underlying bedrock and surrounding topography. Dunes across the solar system aid in our understanding of underlying topography, winds and climate, past and present. Similar patterns can be seen in dunes of the Great Sandy Desert in Australia, where dunes undulate broadly across the uneven terrain and are halted at the margins of sand-trapping lakes. The dune orientations correlate generally with the direction of current trade winds, and reveal that winds must have been similar back when the dunes formed, during the Pleistocene glacial and interglacial periods.
North on Titan is up in the image. Radar illuminates the scene from upper right at a 27-degree incidence angle. The image was obtained during the mission’s 122nd targeted Titan encounter.”
Image credit: NASA/JPL-Caltech/Space Science Institute
ESA dixit:
“On 18 September 2017, ESA astronaut Paolo Nespoli shot this beautiful time-lapse showing the Moon rising above the Earth’s horizon together with Mercury, Mars, the star Regulus, and Venus. ESA astronaut Paolo Nespoli is currently working and living on board the International Space Station as part of his long duration Vita mission.”
Video credit: ESA
NASA dixit:
“June 3, 2016. Rhea, like many moons in the outer solar system, appears dazzlingly bright in full sunlight. This is the signature of the water ice that forms most of the moon’s surface. Rhea (949 miles or 1,527 kilometers across) is Saturn’s second largest moon after Titan. Its ancient surface is one of the most heavily cratered of all of Saturn’s moons. Subtle albedo variations across the disk of Rhea hint at past geologic activity.
This view looks toward the anti-Saturn hemisphere of Rhea. North on Rhea is up and rotated 36 degrees to the right. The image was taken with the Cassini spacecraft narrow-angle camera using a spectral filter which preferentially admits wavelengths of ultraviolet light centered at 338 nanometers. The view was acquired at a distance of approximately 365,000 miles (587,000 kilometers) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 9 degrees. Image scale is 2.4 miles (3.9 kilometers) per pixel.”
Image credit: NASA/JPL-Caltech/Space Science Institute
ESA dixit:
“On 12 September 2017, 710 photos were taken by ESA astronaut Paolo Nespoli to create this time-lapse of the Earth (from Africa to Russia) as seen from the International Space Station. ESA astronaut Paolo Nespoli in currently working and living aboard the Station as part of his long duration Vita mission.”
Video credit: ESA
NASA dixit:
“April 2, 2016. Saturn’s main rings, along with its and moons, are much brighter than most stars. As a result, much shorter exposure times (10 milliseconds, in this case) are required to produce an image and not saturate the detectors of the imaging cameras on NASA’s Cassini spacecraft. A longer exposure would be required to capture the stars as well. Cassini has captured stars on many occasions, especially when a target moon is in eclipse, and thus darker than normal. Dione (698 miles, 1123 kilometers across) and Epimetheus (70 miles, 113 kilometers across) are seen in this view, above the rings at left and right respectively.
This image looks toward the sunlit side of the rings from about 3 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft wide-angle camera. The view was obtained at a distance of approximately 257,000 miles (413,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 34 degrees. Image scale is 15 miles (25 kilometers) per pixel.”
Image credit: NASA/JPL-Caltech/Space Science Institute
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