NATIONAL GEOGRAPHIC'S BEST SPACE PICTURES THIS WEEK CVIII

Week’s Best Space Pictures: Lasers Guide a Telescope’s Gaze
By Michael Greshko, National Geographic News, 29 April 2016.

This week, galaxy clusters shimmer in X-rays, Cassini re-creates the classic “Pale Blue Dot” photograph, and satellites capture a strange seascape.

1. Holey Rollers

On April 18, the team operating NASA’s Curiosity rover used a camera on its arm to inspect its own punctured wheels. The wheels were first damaged in 2013, and should hold up long enough for Curiosity to complete its mission on Mars.

2. Cassini's Pale Blue Dot

While orbiting Saturn, the Cassini spacecraft photographed Earth and the moon. Earth appears as a blue dot at center right, while the moon appears as a faint protrusion from the blue dot’s right side.

3. Bustling in Bolivia

An astronaut aboard the International Space Station snapped this shot of Santa Cruz, Bolivia, one of the fastest-growing cities in the world. The city’s international airport (top right) is the country’s busiest.

4. All That Glitters...

NASA recently removed coverings from the 18 mirrors of the James Webb Space Telescope, seen here. Each mirror is coated in a microscopically thin layer of gold - perfect for reflecting infrared light.

5. Oh, What a Beautiful Morning

This early-morning view from NASA's Curiosity rover was taken on a particularly clear day on Mars, giving the rover an unfettered view of Gale Crater's inner wall.

6. Diamonds and Pearls

These four galaxy clusters were part of a survey investigating dark energy, the mysterious force behind the universe’s accelerating expansion. The images combine X-rays (purple) with optical light (red, green, and blue).

7. Ice Carving?

In this picture from the Landsat 8 satellite, lines crisscross the seafloor of the north Caspian Sea. Scientists think that the marks, which appear in shallow areas, were gouged by winter ice.

8. Sci-Fi Skywatching

On April 26, the ESO’s Paranal Observatory in Chile activated four powerful guidance lasers. The beams energize sodium atoms in the upper atmosphere, creating artificial “guide stars” that calibrate the telescope’s optics.

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