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Monday 10 February 2014

NATIONAL GEOGRAPHIC'S SPACE PICTURES THIS WEEK XCIII


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Week's Best Space Pictures: Black Hole Blasts and Cool Craters
By Dan Vergano,
National Geographic News, 7 February 2014.

A black hole sports supersize jets and Mars shows off its many charms in the week's best space pictures.

1. Black Hole Blast

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A black hole blast erupts from the nearby Centaurus A galaxy, seen in this Chandra X-ray Observatory image released on February 6.

The x-ray jets shoot out from the poles of the "supermassive" black hole at the centre of the galaxy, located some 12 million light-years away. The jets consist of dust and gas ripped from stars by the gravity of the monster black hole.

Most galaxies are suspected to harbour a black hole at their centre, including our own Milky Way, though ours doesn't display such dramatic jets. The smaller lights in the Chandra image, which combines views of Centaurus A taken from 1999 to 2012, are smaller black holes.

2. Aurora Bakes Over Alaska

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Baked Alaska, anyone? The northern lights glimmer over the town of North Pole, Alaska, in this view of the glimmering skies submitted to National Geographic's Your Shot on February 2.

The sun is now at its "solar maximum," sending a lot of solar storms our way. The activity has been a boon to fans of auroras.

3. Ancient Chinese Lake Puts Salt on the Table

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If only french fries could talk. They might tell the salty story of their connection to China's ancient Lake Qarhan, seen in this Landsat 8 satellite view published on on February 2.

The salt lake, the remnant of a lake more than two million years old, serves as a source of table salt, potash, and gypsum. Located on a high plateau, its waters readily evaporate to leave behind minerals in the green pens located on its edges and seen in the orbital view.

Lake Qarhan spans some 2,261 square miles (5,856 square kilometres). It is a playa - a lake that fills only seasonally - that contains nine smaller, more permanent salt lakes.

4. Mars' Fresh Impact Crater

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Yowch! Mars sports a spanking fresh impact crater in this Mars Reconnaissance Orbiter image released on February 2.

Our solar system is a shooting gallery and Mars bears the marks to prove it, with about 200 impacts leaving craters more than 12.8 feet (3.9 meters) wide every year on the red planet.

"Few of the scars are as dramatic in appearance as this one," says the spacecraft's team in a statement on the image.

The enhanced colour view reveals bluish dust ejected from the impact, spread in rays across the surface of Mars. The blast spread ejected some 9.3 miles (15 kilometres) away from the impact.

5. Halo Crowns Sun on Tenerife

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PHOTOGRAPH BY STEFAN SEIP, TWAN

A halo shines around the sun, shown in this startling sky shot, taken from Tenerife, located in the Canary Islands.

Atmospheric halos form around the sun (or moon) when their light is bent by ice crystals that hang high in upper-atmosphere clouds. The six-sided shape of the ice crystals bends the sunlight in the same way, focusing the light like a lens to produce the halo.

The rock formation blocking the sun in this view of the halo is called Roque Cinchado, an emblem of Tenerife.

6. Frosts Crawls Across Red Planet

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Frost glimmers on the ancient sand dunes of Mars, revealed by this Mars Reconnaissance Orbiter image released on February 5.

The beautiful dune ripples of Russell Crater, seen in the picture, serve as a favourite landmark for scientists scouting out the seasons on the red planet.

The frost adorning the dunes is made out of frozen carbon dioxide, better known as dry ice. As the season grows warmer on Mars, the frost turns to carbon dioxide gas and escapes into the atmosphere. Scientists measure this decline in the frost to watch the march of the seasons on Mars.

Follow Dan Vergano on Twitter and Google+.

[Source: National Geographic News. Edited.]


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