Retrograde Mars
Credit & Copyright: Tunç Tezel (TWAN)
Explanation: Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth’s sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun. During the most recent such pass over the last year, the proximity of Mars made the red planet appear larger and brighter than usual. Also during this time, Mars appeared to move backwards in the sky, a phenomenon called retrograde motion. Pictured above is a series of images digitally stacked so that all of the stars images coincide.
Retrograde Mars
Credit & Copyright: Tunç Tezel (TWAN)
Explanation: Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth’s sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun. During the most recent such pass over the last year, the proximity of Mars made the red planet appear larger and brighter than usual. Also during this time, Mars appeared to move backwards in the sky, a phenomenon called retrograde motion. Pictured above is a series of images digitally stacked so that all of the stars images coincide.
Until late this month, the Red Sea north of Rugged Island was glassy and clear — and then a new island emerged almost overnight. Yes, that smoking mass of land above is an infant isle, formed by a volcanic eruption. Fishermen off the coast of Yemen witnessed lava fountains 90 feet (30 meters) tall on December 19, 2011; by December 23, what had once been unbroken water surface was now a new chunk of land.
The plume in the photo, captured by NASA’s Earth Observing-1 satellite, is likely a mix of volcanic ash and water vapor. The new island is part of the Zubair Group, a line of islands arising from a shield volcano under the Red Sea. In this area, the Red Sea Rift, the African and Arabian tectonic plates are slowly pulling apart, and new ocean crust regularly formsDammit, I got the new National Geographic huge-ass Atlas of the World* for Christmas, and it’s already out of date!
*It’s not a coffee table book, it’s a coffee table. I look like a child when I read it. It’s enormous. I love it.
