NATIONAL GEOGRAPHIC'S SPACE PICTURES THIS WEEK XXVII

Space Pictures This Week: Mars Tracks, Auroras, More
By Daniel Stone, National Geographic News, 9 September 2012.

1. Mars Tracks

After landing safely on Mars last month, NASA's Curiosity rover (right) has begun its journey to a nearby canyon. Captured by the Mars Reconnaissance Orbiter from high above the red planet, this colour-enhanced image, released Thursday, shows Curiosity's tracks.

The orbiter's high-powered cameras were designed to detect even slight details on the planet's surface. The sky crane that lowered Curiosity onto Mars threw up enough dust that scientists back on Earth can now see a darker, more mysterious rocky substrate below-the blueish spots at centre.

(Related: "Mars Rover Landing a Success—What Happens Now?")

2. Curiosity Self-Portrait

After nearly 30 days on Mars, the camera atop Curiosity snapped this picture of the rover's right arm. The self-portrait has some utility. NASA scientists were able to spot a thin layer of Martian dust on the Mars Hand Lens Imager.

Mars rovers in the past have succumbed to the effects of the dusty, barren planet. NASA's Spirit rover, which landed on the red planet in 2004, was unable to continue in 2010 after the solar panels that powered the craft had become too dusty to accept new solar radiation.

(See colour pictures from Mars.)

3. Sibling Galaxies

In an unusual image taken with the Hubble Space Telescope and released Wednesday, a pair of galaxies, collectively known as Arp 116, are clearly visible in the same frame. The larger system (centre), known as Messier 60, is approximately 55 million light-years from Earth. The smaller one, called NGC 4647, is thought to be more than 63 million light-years away.

Scientists have long wondered whether the two systems, being so close together, affect each other. So far no stars have been found forming between the two, which would indicate significant interaction, but recent studies suggest some minor gravitational impacts.

(Related pictures: "Hubble Space Telescope at 20.")

4. Clouded Colours

Vivid enough to compete with a bright moon, the colours of an aurora bleed through the clouds on Tuesday near Edmonton, Canada.

Most often visible in Arctic and Antarctic regions, auroras shed a unique light, created when charged particles from the sun interact with the Earth's atmosphere and magnetic field. (See more aurora pictures.)

5. A Storm's Spectrum

After an uneventful storm chase in Nebraska Tuesday, photographer Mike Hollingshead headed home. Along the way he noticed auroras above storm clouds. The result: a night sky filled with colours, including reflected moonlight.

(New Aurora Pictures: Solar Flare Sparks "Snakes," "Spears.")

6. Superbubble

Embedded in a huge dust-and-gas cloud within a satellite galaxy of our own Milky Way, the star cluster NGC 1929 glows blue and hot in X-ray wavelengths captured by the Chandra space telescope and shown in a composite picture released August 30.

Shock waves from exploding stars within NGC 1929 have helped clear a vast cavity, or superbubble, in the cloud, whose cooler regions appear red via infrared imagery from the Spitzer Space Telescope. Yellowish areas show ultraviolet light from young, intensely burning stars, seen via optical imagery from a telescope at the La Silla Observatory in Chile.

(Related: "Massive Star Collision Spotted by Hubble.")

7. Parting Shot

After staying more than a year in the orbit of the monstrous asteroid Vesta, NASA's Dawn spacecraft broke free on Tuesday, but not before snapping one last image of the rock's north pole (above). Data from Dawn has helped scientists discover that the asteroid had experienced two major collisions as far back as two million years ago, producing ripples and shock waves on the rocky surface.

Dawn will now travel to Ceres, a roughly 600-mile-wide (950-kilometre-wide) dwarf planet in the solar system's asteroid belt, between the orbits of Mars and Jupiter. (Related: "Astronauts Could Ride Asteroids to Mars, Study Says.")

8. Sweet Building Blocks

In this cluster of light surrounding the baby star IRAS 16293-2422, scientists have discovered a simple form of sugar called glycolaldehyde. The NASA researchers detected the tiny molecules using a highly sensitive detector called the Atacama Large Millimetre/submillimetre Array (ALMA).

Sugar is a building block of life, and the new observation, announced August 29, is said to be the first to place the substance in a planet-forming region around a young star. (See "Star Found Shooting Water 'Bullets.'")

[Source: National Geographic News. Edited.]