Space Pictures This Week: Sun Halo, Galaxy Swarm, More

Sun Circle

Photograph by Tho Le Duc, My Shot

Seen from Hai Duong, Vietnam, the bright sun sports a rainbow-colored halo in a picture taken September 17.

The circle of color is an optical effect created as ice crystals in high-altitude clouds refract, or bend, light. Because the upper reaches of Earth's atmosphere are almost always below freezing, sun halos and related phenomena—such as sun dogs and pillars—can be seen year-round, according to NASA.

Published September 22, 2011

Venetian Curves

Image courtesy European Space Imaging

Water taxis dart like comets through the waters around Venice in a satellite picture of the Italian city recently released by the European Space Agency.

At the top in this frame, the Grand Canal can be seen curving through the southern part of the central districts toward the Piazza San Marco. At bottom are the islands of Giudecca (left) and San Giorgio Maggiore.

(Read "Vanishing Venice" in National Geographic magazine.)

Published September 22, 2011

Galactic Swarm

Image courtesy ESA/NASA

Galaxies seem to dance like fireflies in a new picture of part of the Coma galaxy cluster taken by the NASA/ESA Hubble Space Telescope and released September 19.

The brightest galaxy at top right is NGC 4874, a giant elliptical galaxy about ten times larger than our Milky Way. Recently astronomers found that NGC 4874 hosts its own cluster within a cluster: The galaxy's strong gravitational pull allows it to hold onto a swarm of globular star clusters and a few dwarf galaxies.

Published September 22, 2011

Green Flash

Photograph by Amir Abolfath, TWAN

Light being bent by Earth's atmospheric layers gives the setting sun a squashed appearance in a recently released picture taken through a telescope from the Zagros Mountains of Iran.

The image also captured a so-called green flash near the top of the sun. This brief phenomenon can happen when the sun is seen through clear skies near the horizon.

Earth's atmospheric layers bend, or refract, light like a prism in such a way that green light appears to be coming from a slightly higher position than orange or red.

(Also see pictures of a green flash over the moon.)

Published September 22, 2011

Homeward Bound

Photograph by Sergei Ilnitsky, Pool/AP

A Soyuz spacecraft drifts back to Earth carrying a NASA astronaut and two Russian cosmonauts in a picture taken September 16. The trio landed safely in Kazakhstan after spending more than five months aboard the International Space Station.

The return of Alexander Samokutyaev, Andrey Borisenko, and Ronald Garan wasn't without some drama: Mission control in Moscow reportedly lost contact with the craft for a few minutes during its descent, but communications were reestablished as the capsule neared touchdown outside the city of Dzhezkazgan.

Published September 22, 2011