NATIONAL GEOGRAPHIC'S BEST SPACE PICTURES THIS WEEK XIII

Best Space Pictures: A Black Hole Blows, Waters Recede, and a Mountain Erupts
By Jane J. Lee, National Geographic News, 20 June 2014.

Astronauts watch soccer from space, stars light up the night sky, and a galaxy gets a ring in this week's best space pictures.

1. Historic Serbian Floods

An instrument on NASA's satellite Terra captures the soggy aftermath of historic flooding west of Belgrade, Serbia (map), in an image released June 12. The ground remains so saturated with river water (coloured red), that it's still uninhabitable.

The flooding, detected using Terra's thermal sensors, covers an area some 35 by 21 miles (56 by 34 kilometres) in size. The recent deluge is the worst to hit Serbia since officials started keeping track of rainfall there 120 years ago.

2. A Mysterious Ring

The European Space Agency's Herschel space telescope pictured a puzzling ring (top, centre) in the middle of a stellar nursery in this image released on June 12. The nursery, labelled NGC 7538, contains clumps of gas that astronomers believe could eventually give rise to O-type stars, the most massive stars in the universe.

Violent winds given off by these stars can result in bubble- or ring-shaped formations in their surrounding cloud of gas and dust. The death of O-type stars, in the stellar explosions called supernovae, can also produce these structures.

However, the remains of such a star are absent in the middle of this particular ring. It's possible that one of the enormous stars blew this bubble, then scooted away before researchers were able to detect it, leaving behind the ring.

3. Night Lights

Photograph by Noah G., National Geographic Your Shot

The lights from nearby houses splash brightly across the side of an old barn in an image submitted to Your Shot June 14. The Milky Way galaxy glows softly in the background.

4. Satellite Stadium

The International Space Station (ISS) captured a picture of Brazil's national football stadium (top, left) in Brasilia (map) in an image released June 16.

The round stadium's white rooftop makes it easily visible from on high. Upgrades made to this soccer shrine in time for the 2014 World Cup make it the second most expensive stadium in the world after London's Wembley Stadium.

5. Rivalry in Orbit

NASA astronauts Reid Wiseman (left) and Steve Swanson (centre) watch ten minutes of a World Cup match with German astronaut Alexander Gerst (right) aboard the International Space Station in an image released June 18. They caught the match in between performing their duties on the orbiting station.

Though the astronauts sent a message wishing luck to all the players competing in this year's World Cup, they plan to root for their home teams when the U.S. plays Germany on June 26.

6. Fiery Etna

Photograph by Marco Calandra, National Geographic Your Shot

Mount Etna, Europe's tallest active volcano, puts on a show in an image submitted to Your Shot on June 18. Stars wheel above an outburst of lava flowing down the side of the volcano, located in Sicily, Italy.

7. Supermassive Blockage

Here's a baffling mystery - a black hole that seems to blast material away from its all-consuming maw. Astronomers recently found just such a massive stream of gas flowing away from the supermassive black hole nestled in the centre of galaxy NGC 5548 (pictured above).

The stream is blocking about 90 percent of the x-rays normally emitted by the black hole, forcing experts to rethink the celestial system's behaviour.

Here's what they think is happening: Typically, when matter falls toward a black hole, it piles up within a flat accretion disk surrounding the collapsed star. The inner portions of the disk emit x-rays, while the outer parts emit ultraviolet radiation. In this black hole, dust shields the x-rays emitted closer to the black hole, which allows the the UV radiation to whip up winds powerful enough to blow gas away from the black hole. (See "Jumbo Black Hole's Dizzying Spin Twists Space.")

NGC 5548 is known for its strong winds, which can exceed 2.2 million miles (3.5 million kilometres) an hour. However, this new gas outflow could be powered by surprisingly strong winds up to 11.2 million miles (18 million kilometres) an hour, Hubble space telescope researchers report June 19 in the journal Science.

[Source: National Geographic News. Edited.]