NATIONAL GEOGRAPHIC'S BEST SPACE PICTURES THIS WEEK XXXV

Week's Best Space Pictures: Cosmic Web, Martian Vistas, and Earth From Above
By Nadia Drake, National Geographic News, 21 November 2014.

A volcano awakens, scientists spin a massive cosmic web, and NASA's Mars rover continues to climb Mount Sharp in this week's best space pictures.

1. Giant Galactic Web

Galaxies aren't splashed uniformly across the universe. Rather, they're strung into immense cosmic webs, with glittering galactic filaments woven around vast, hollow voids.

Scientists trying to understand how these massive structures form have used computers to spin their own cosmic webs. The simulation above, produced by the Illustris Project, shows how dark matter (in blue) and gas (in orange) are distributed in a giant galactic cluster stretching roughly 300 million light-years across.

Recently, a different team of scientists observed that the supermassive black holes churning away in the hearts of galaxies tend to rotate along parallel axes - even when the galaxies are separated by billions of light-years. It's a startling observation, and one that suggests we have much still to learn about how these large-scale structures form.

2. Illuminated, Earthly Footprints

Florida's distinct shape is visible even at night. In this photograph taken October 13 by astronauts aboard the International Space Station, lights from the Sunshine State's cities glimmer beneath moonlit clouds, revealing the region's most densely populated areas. One of those areas is definitely not in the peninsula's southwest, where a dark blotch betrays the presence of the almost-unpopulated Everglades wetlands.

Trickling south from the peninsula are the Florida Keys, and sparkling 56 miles (90 kilometres) offshore in the Atlantic Ocean (at right) is Freeport, on Grand Bahama Island.

3. Superheated Plasma Loop

A streamer of superheated particles arches high above the sun's surface on November 9. Driven by magnetic forces, these eruptions sometimes hurl blobs of energetic, ionized particles into space.

If Earth happens to be in the way, watch out: The most powerful geomagnetic storms are capable of knocking out ground- and space-based communication systems. But it's not all bad. An active sun sometimes means that gorgeous auroras are visible even at low latitudes. (See stunning aurora pictures.)

4. Mysterious Martian Ridge

It's a scene that could be mistaken for parts of the American Southwest. But this is the surface of Mars, seen through the lens of NASA's rover Curiosity on October 7.

That weird little ridge of rocks in the middle, named the Pink Cliffs, appears to be resistant to the wind erosion that has flattened the surrounding terrain, which is in the Pahrump Hills at the base of Mount Sharp. The rover is going to spend a little time here figuring out what's going on before continuing to climb the mountain.

5. Graceful Martian Hills

On its 807th Martian day (which happened to be November 13), NASA's Curiosity rover took this picture of the Pahrump Hills outcrop at the base of Mount Sharp. Here, the dusty, cracked foreground landscape gives way to sandy, wind-sculpted hills.

Curiosity is continuing its trek up Mount Sharp, which rises 3.4 miles (5.5 kilometres) from the base of Gale Crater. (See more pictures from Curiosity.)

6. Boom Goes the Volcano

After a year-long snooze, Alaska's most active volcano roared back to life in early November and began sending fountains of lava and volcanic debris tumbling down its slopes.

By the time Landsat 8 flew overhead on November 15, Pavlof's ash plume had reached an altitude of nearly 30,000 feet (9 kilometres). The next day, though, the volcano abruptly fell asleep…for now.

Photo gallery by Adrian Coakley.

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