Space Pictures This Week: Mercury’s Marks, Miracle Delta


1. Wind Shadow

Week in Space 250 - Picture of ripples in the ocean coming off of the Canary Islands in the Atlantic Ocean

Image courtesy Jeff Schmaltz, MODIS/NASA

Milky-colored ripples on the Atlantic Ocean trail behind the Canary Islands (map) off the west coast of Africa in this June 15 image snapped by NASA’s Terra satellite.

Thanks to a vantage point 450 miles (725 kilometers) above the Earth, strange patterns caused by strong winds on the ocean’s surface become visible in the play of sunlight on the water.

The rocky, volcanic islands redirect the strong northwest winds that come up against the coast, forming a wind shadow on the southwest side of the islands. This shadow creates distinct helical cloud trails and alternately smooth and choppy waters, which change how light is reflected.

—Andrew Fazekas

2. Night Light

Week in Space 250 - Picture of northern lights above Fairbanks, Alaska

Photograph by Dennis Mammana, TWAN

Like a celestial pipe organ in a grand cathedral, the skies above Fairbanks, Alaska, come alive with a curtain of green auroras in this image snapped in March. (Learn how a stunning aurora video was made.)

“‘Normal’ photos tend to blur [auroras] and don’t capture the true detail of these marvelous curtains, so to freeze the action as much as possible, I kept my exposure time to only a second,” said photographer Dennis Mammana on The World At Night website.

3. Galactic Penguin

Week in Space 250 - Picture of two galaxies colliding such that they look like a penguin guarding its egg

Image courtesy STScI/AURA/ESA/NASA

The Hubble Space Telescope snapped this uncanny image, released June 20, of two interacting galaxies that look like a penguin guarding her egg.

Known collectively as Arp 142, the galactic pair lie some 326 million light-years from Earth in the constellation Hydra.

Over a period of millions of years, the celestial bird-shaped galaxy has lost its distinct pinwheel structure. Its red, spiral arms have become distorted by the pull of gravity from the neighboring elliptical, egg-shaped galaxy.

Above the pair is a lone, unrelated bluish galaxy located about 230 million light-years from Earth.

4. Miracle Delta

Week in Space 250 - Picture of the Okavango river emptying into the Okavango delta as imaged by the European ENVISAT orbiter

Image courtesy ESA

This radar satellite image, released June 7, shows where southwestern Africa’s Okavango River (bright yellow) empties into the Okavango Delta in northern Botswana. (Read about “Africa’s Miracle Delta” in National Geographic magazine.)

This portrait of one of the most popular safari destinations on the continent is a composite based on images taken by the European ENVISAT orbiter between September 2009 and October 2010.

The Moremi Game Reserve appears in purple at the center of the image, while in the lower right corner a cluster of reflections marks the town of Maun.

5. Mercury’s Marks

Week in Space 250 - Picture of impact craters on Mercury   Image courtesy JHUAPL/NASA

This high-resolution image of the craggy surface of Mercury, released June 20, was taken by the cameras aboard NASA’s MESSENGER orbiter. Multiple impact craters with fresh ray patterns appear scattered across an ancient lava basin.

Slightly larger than Earth’s moon, Mercury lacks a meaningful atmosphere, so there is nothing to stop impacts from occurring and covering its sun-scorched surface with craters.

6. Where There’s Smoke

Week in Space 250 -  satellite photo shows smoke from wildfires in Asia  Image courtesy Jeff Schmaltz, MODIS/NASA

The root cause of the record-setting pollution levels that have besieged Singapore this past week is clearly seen in this orbital photo from NASA’s Aqua satellite taken on June 19.

Thick clouds of smoke originating from illegal wildfires on Sumatra (below, left) appear to blow straight toward southern Malaysia, where a choking haze of pollutants has blanketed Singapore. (Related: “Pollution in Singapore Hits Record Level.”)

7. Stellar GemsNGC 3766 star clusterImage courtesy ESO

Shining like a collection of cosmic jewels 7,000 light-years from Earth, the open star cluster pictured above has revealed a previously unknown type of variable star.

Using a large telescope in the high Atacama Desert in Chile, a group of Swiss astronomers spent seven years studying and measuring the brightness of NGC 3766, a loosely packed group of 3,000 stars in the southern constellation Centaurus. Researchers discovered that 36 member stars within the constellation had highly unusual and never-before-seen patterns in the fluctuation of their brightness.

The cause of these changes in light output is yet to be determined, but astronomers are saying that the very existence of this new class of suns is a challenge to our understanding of stellar life cycles.

Courtesy : National Geographic

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