Space Shuttle Discovery
#WhatIsNASAFor? continuing the human tradition of exploration.
Dark Sky Island
The gorgeous Isle of Sark, the smallest self-governing island in Europe, is located in the English channel 130 miles off the southern English coast. In January 2011 it became the world’s first “Dark Sky island” by controlling light pollution. The island’s single electricity source is an oil-fired power station, and there are no cars, streetlights or even paved roads: you can only get around by bike, horse, carriage or tractor-drawn bus. Due to the lack of light pollution, the Milky Way stretches gloriously overhead—from horizon to horizon across the pristine black sky.
Saturn’s rings cut across an eerie scene that is ruled by Titan’s luminous crescent and globe-encircling haze, broken by the small moon Enceladus, whose icy jets are dimly visible at its south pole.
The scattered light around planet-sized Titan (5,150 kilometers, or 3,200 miles across) makes the moon’s solid surface visible in silhouette. Enceladus (505 kilometers, or 314 miles across) enjoys far clearer skies than its giant sibling moon.
This view shows the unlit side of Saturn’s rings.
High cliffs surrounding Echus Chasma on Mars
What created this great cliff on Mars? Did giant waterfalls once plummet through its grooves? With a four-kilometer drop, this high cliff surrounding Echus Chasma, near an impressive impact crater, was carved by either water or lava. A leading hypothesis is that Echus Chasma, at 100-kilometers long and 10-kilometers wide, was once one of the largest water sources on Mars. If true, water once held in Echus Chasma likely ran over the Martian surface to carve the impressive Kasei Valles, which extends over 3,000 kilometers to the north. Even if initially carved by water, lava appears to have later flowed in the valley, leaving an extraordinarily smooth floor. Echus Chasma lies north of tremendous Valles Marineris, the largest canyon in the Solar System. The above image was taken by the robotic Mars Express spacecraft currently orbiting Mars.
Image credit: G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA
Science and Space Posters by Ron Guyatt