NATIONAL GEOGRAPHIC'S BEST SPACE PICTURES THIS WEEK XXIV

Week's Best Space Pictures: Sun Blazes, Saturn Shadows a Moon, and Mercury Sports a Blast Crater
By Dan Vergano and Jane J. Lee, National Geographic News, 5 September 2014.

Mercury shows off a weird crater, a spacecraft visits an oncoming comet, and Iceland erupts in this week's best space pictures.

1. Bright Sides

This composite image - released September 3 - showing the sun's bright, active regions over the course of one year allows researchers to follow the migration of these spots from the poles to lower latitudes.

Tracking such bright points of light enables scientists to better time solar cycles, which are roughly 11-year periods in which the sun shifts from active to inactive states. Knowing when the sun will move into an active state is important because during these times massive blasts of supercharged particles - known as coronal mass ejections - can wreak havoc with electronic systems on Earth.

2. Smog Blankets Beijing

Photograph courtesy of Jeff Schmaltz, LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC

A view of smog is striking from space, and certainly beats experiencing it from the ground, as this view released on September 2 from a NASA satellite attests.

Taken last December by the Terra satellite, the picture shows a band of heavy pollution headed toward Beijing. Similarly smoggy skies hovered over Europe and North America in the past century, before anti-pollution laws were enacted.

3. Comet Countdown

A visitor to a tiny world, the Rosetta spacecraft is imagined after its landing on a comet in this illustration released by the European Space Agency.

The spacecraft is only two months away from its real landing on comet 67P/Churyumov-Gerasimenko, with its famously strange, double-lobed appearance that some have compared to a rubber duck. Just this week, Rosetta's instruments started returning spectral information on the chemistry of the comet's surface.

4. Seuss Crater Shines

In orbit around Mercury, NASA's MESSENGER spacecraft captured this colourful view of a crater named Seuss over the summer.

A "complex" crater, Seuss is pockmarked with bright blue hollows, with orange streaks of ejected material radiating away from its centre. The brown edges of the crater were likely excavated in the impact that created the hole.

5. Infrared Reveals Ice Age Ridges

Photograph by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./

Japan ASTER Science Team

Flying high over Washington State, a NASA satellite's infrared glimpse of farmland reveals ripples left by the passage of Ice Age glaciers.

The Terra satellite's view of farmland near LaCrosse, Washington, shows humps and hollows - hills crushed by glaciers long ago. The silty soil holds moisture, making it perfect for farming, particularly wheat.

The false-colour infrared image depicts the best-growing cropland in red and fallow land in brown.

6. Saturn Moon Circles in Shadow

In the shadow of Saturn's rings, the tiny moon Mimas stands out as a white pinpoint (lower left) against the planet's dark rings.

The view was captured by the Cassini spacecraft when it was about a million miles (1.6 million kilometres) from Mimas. The moon itself is some 246 miles (396 kilometres) wide.

7. Iceland Volcano Erupts

Photograph by Jeff Schmaltz, LANCE/EOSDIS Rapid Response and Jesse Allen, using EO-1 ALI data provided

courtesy of the NASA EO-1 team

The Earth erupts near Iceland's Bárđarbunga volcano, in this September 1 view from space released by NASA's Terra spacecraft.

Announced by earthquakes in August, the eruption has triggered aviation warnings even though little ash has accompanied its emergence. The magma bed now covers more than 2.8 square miles (7.2 square kilometres) of mountainous terrain in central Iceland.

Photo edit by Mallory Benedict.

[Source: National Geographic News. Edited.]