NATIONAL GEOGRAPHIC'S SPACE PICTURES THIS WEEK LII

Space Pictures This Week: Mars Gullies, Aurora Borealis, and Dragon Detaches
By National Geographic News, 29 March 2013.

1. Swirling Galaxy

With its high-powered lenses, the Hubble Space Telescope captured this image of the spiral galaxy Messier 77, a large group of stars 45 million light-years from Earth. The colours of the spiral in this image released March 28 reveal that new stars were formed in the red and blue areas. The overall glow indicates that the entire system is rich with ionized gas.

2. Detached

After it docked with the International Space Station last month to deliver supplies, the SpaceX Dragon spacecraft successfully detached from the station to return to Earth, as pictured in this image taken March 26. SpaceX was the first private company to successfully link a spacecraft with the ISS, which is collectively run by a coalition of countries. (Related: "SpaceX's Dragon Docks With Space Station—A First.")

3. Red Planet Gullies

Gullies on the surface of Mars, likely formed by defrosting carbon dioxide, offer clues about its past and about the presence of water that may have once run over the red planet. NASA scientists use a high-resolution camera, called the High Resolution Imaging Science Experiment, on-board the Mars Reconnaissance Orbiter to capture detailed images like this one released March 20. (Learn about evidence for mega flooding on Mars.)

4. Ocean Portrait

As it passed over the Indian Ocean on March 11, NASA's Aqua satellite snapped this photo of clouds moving from northwest to southeast. The Aqua satellite was launched in 2002 as part of an ambitious effort to study Earth's water cycle. As it circles the planet, the satellite observes oceans, cloud layers, and ice, as well as soil moisture and atmospheric vapour.

5. Painted Sky

Photograph by Babak Tafreshi, TWAN

Late winter provides excellent opportunities to see aurora borealis, known as the northern lights, in Norway. As the earth tipped into its vernal equinox on March 20, signalling the beginning of spring in the Northern Hemisphere, astronomy photographer Babak Tafreshi made this photograph while overlooking a fjord in the Norwegian Sea near Tromso (map). (See more pictures of auroras from February and March.)

6. White Rock

Released March 18, this close-up photo taken by the Mars rover Curiosity shows a small, fragmented rock named Tintina. Scientists have not been able to fully identify the bright white material on the rock's surface.

7. Graceful Prominence

NASA's Solar Dynamics Observatory captured this image on March 16 as a solar prominence broke apart several thousand miles above the surface of the sun. The image, captured in ultraviolet light, shows a cloud of particles that hovered near the eruption before fading away into space.

Guided by the sun's magnetic field lines, solar prominences can hover over the surface of the sun for days or weeks before erupting. The eruptions can take minutes to hours.

8. Sapphire Pond

As spring and summer bring heat to the Greenland ice sheet, blue pools of meltwater form that eventually carve paths to the ocean. This photo, released March 21, was taken by NASA's Earth Observing-1 satellite, which was designed to capture detailed geographic images.

Scientists have taken a heightened interest in these pools and the large cracks - known as moulins - that they form, in an effort to research the acceleration of melting ice sheets and the calving of glaciers. (Related: "'Shocking' Greenland Ice Melt: Global Warming or Just Heat Wave?")

[Source: National Geographic News. Edited.]