NATIONAL GEOGRAPHIC'S BEST SPACE PICTURES THIS WEEK LIV

Week's Best Space Pictures: A Storm Swirls and Dark Matter Collides
By Jane J. Lee, National Geographic News, 3 April 2015.

A typhoon menaces the Philippines, and galaxies - and their dark matter - collide, in this week's best space pictures.

1. Dark Collisions

Photograph via NASA's Chandra X-ray Observatory

This is what it looks like when 72 galaxy clusters collide. The image, made by combining an x-ray view with visible light data, isn't just a pretty picture: Researchers use images like this to study how dark matter interacts with itself.

2. Bone Dry

Viewed from space, the Sahara reveals its past. Much of what's now desert used to be covered with a huge lake that stretched from the foreground to the Tibesti Mountains (upper left). Lake Chad, the green smudge in the bottom centre, is all that's left.

3. A Long Commute

An astronaut and two cosmonauts hitch a ride to work on the International Space Station aboard a Soyuz TMA-16M spacecraft on March 27. Astronaut Scott Kelly and cosmonaut Mikhail Kornienko will spend a year in space before coming back home.

4. Cosmic Yardstick

Spiral galaxy NGC 3021 (right) is quite the glittery celestial ruler because it contains Cepheid variable stars, which pulse in brightness. By measuring the pulse rate, astronomers can work out the distance between Earth and the galaxy.

5. Mineral Veins

The Curiosity rover imaged a network of "veins" running across Mars' landscape. Each about 2.5 inches (4 centimetres) high, the veins formed when liquid seeped through cracks in the rock and deposited minerals, then the surrounding material eroded.

6. A Monster Storm

Astronaut Samantha Cristoforetti snapped a picture of Supertyphoon Maysak as the International Space Station flew over the category 5 storm on March 31. The monster is forecast to hit the Philippines on April 5.

Photo gallery by Mallory Benedict.

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