Seasonal frost commonly forms at middle and high latitudes on Mars, much like winter snow on Earth. However, on Mars most frost is carbon dioxide (dry ice) rather than water ice. This frost appears to cause surface activity, including flows in gullies. via NASA http://ift.tt/1LZCz3H

Africa is front and center in this image of Earth taken by a NASA camera on the Deep Space Climate Observatory (DSCOVR) satellite. via NASA http://ift.tt/1Ky6MX2

This July 11, 2015 photograph captures one of the final, if not the final, James Webb Space Telescope flight primary mirror segments to be processed through NASA Goddard Space Flight Center’s Calibration, Integration and Alignment Facility (CIAF). via NASA http://ift.tt/1JODnSV

This photograph, taken on May 4, 2015 by an astronaut onboard the International Space Station, highlights one of the most active volcanic regions on Earth: the Kamchatka Peninsula in far eastern Russia. The three largest volcanoes visible at image center include Kliuchevskoy, Bezymianny, and Ushkovsky. via NASA http://ift.tt/1VJ4BUb

Four images from New Horizons’ Long Range Reconnaissance Imager (LORRI) were combined with color data from the Ralph instrument to create this enhanced color global view of Pluto. via NASA http://ift.tt/1VF7vsW

This 70mm frame shows the 50,162-pound Chandra X-ray Observatory before it was tilted upward for its release from the Space Shuttle Columbia’s payload bay on July 23, 1999, just a few hours following the shuttle’s arrival in Earth orbit. Chandra was spring-ejected from a cradle in the payload bay at 6:47 a.m. Central time. via NASA http://ift.tt/1IgnfbE

The Soyuz TMA-17M launched from the Baikonur Cosmodrome in Kazakhstan to the International Space Station at 5:02 p.m. EDT (3:02 a.m. on July 23 Baikonur time). via NASA http://ift.tt/1CVFJ5f

The Soyuz TMA-17M launched from the Baikonur Cosmodrome in Kazakhstan to the International Space Station at 5:02 p.m. EDT (3:02 a.m. on July 23 Baikonur time). via NASA http://ift.tt/1RRKjZ8

The 2015 wildfire season in the Arctic has been very intense – and very smoky. As of July 15, over 3,190,000 acres had burned across Canada, according to Natural Resources Canada. According to the National Oceanic and Atmospheric Administration (NOAA), more than 600 fires had burned millions of acres in Alaska as of July 7. via NASA http://ift.tt/1Oxot7X

Pluto’s icy mountains have company. NASA’s New Horizons mission has discovered a new, apparently less lofty mountain range on the lower-left edge of Pluto’s best known feature. via NASA http://ift.tt/1gMQrRI