NATIONAL GEOGRAPHIC'S BEST SPACE PICTURES THIS WEEK XXIII

Week's Best Space Pictures: A Martian "Footprint," a Fledgling Star, and an Erupting Island
By Jane J. Lee, National Geographic News, 29 August 2014.

Mars sports a weird crater, a young star gleams in its own reflection, and a new island continues a fiery growth spurt.

1. Martian "Footprint"

Sadly, this isn't the gigantic footprint of a long-lost Martian dinosaur, despite all appearances.

Instead, this overhead view from NASA's Mars Reconnaissance Orbiter reveals an oblique impact from a meteorite that struck the surface of the red planet while flying on a nearly horizontal path.

Released August 27, the photograph of this crater shows ejecta, or debris, thrown out in two directions (top right) rather than in all directions. (Read about turning Mars into the new Earth in National Geographic magazine.)

2. Twinkle, Twinkle

A young star ignites amid the Perseus constellation, in this image released August 25 by the European Space Agency. The fledgling star (bright dot in the middle) is seen throwing off jets of yellowish gas. (See "Stunning Snapshot Reveals Dazzling Star Factory.")

Below it swirls a clump of gas known as a "reflection nebula." The gas clouds reflect light from the stars embedded within the nebula, which produces its ethereal glow. These stars sculpt the gas into the wisps visible in the image above. (See more pictures of nebulae.)

3. Huff and Puff

The Pacific Ocean's latest addition, a new island that broke the ocean's surface over nine months ago, continues to spew lava and smoke in this space agency image released on August 29.

The island, called Nishino Shima, is located about 620 miles (a thousand kilometres) from Japan's coast. (See "Japan's Newest Island Is Now Eight Times Bigger.")

NASA's Landsat 8 satellite captured the still-active volcano belching smoke into the western Pacific sky. All the activity has also turned the water around the island a light green and yellow. (Watch the volcano erupting.)

4. Neptune's Weather

August 25 was a milestone date for Neptune, thanks to two Earthly visitors. NASA's latest outer solar system mission, the New Horizons spacecraft, just passed the orbit of this lovely blue planet on that date. That's exactly 25 years after Voyager 2 snapped this photograph of a cloudy day there in 1989. (Learn about about the history of the Voyager missions.)

The clouds forming a dark smudge on Neptune's lower left side circles the planet once every 18.3 hours, while the dark oval on the lower right side circuits every 16.1 hours.

5. Birth of a Galaxy

Stars spark to life during the birth of a young galaxy in an illustration released by the European Space Agency on August 27. This view is depicted as seen from a hypothetical planetary system circling the star.

6. Glacial Tongues

Some of Greenland's glaciers snake out to sea (top left side of image) in an image released by NASA on August 24.

Once these ice floes break off and become sea ice, winds and ocean currents whip them into swirls seen in the Fram Strait between Greenland and Svalbard (map).

[Source: National Geographic News. Edited. Some links added.]