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Star dunes

Thu, 10 Dec 2009 04:14:12 GMT

clipped by: amgumen

Linear dune chains are usually generated roughly parallel to the dominant winds. It also seems to be true that linear dunes are built by stronger winds. This detailed astronaut photograph shows that smaller dunes, known as star dunes, are built on top of the linear dunes. Star dunes seem to form in weak wind regimes, in which winds blow from different directions in each season, resulting in characteristic “arms” snaking away from a central point. Some scientists therefore think the dunes in this image were generated in two earlier climatic phases, different from that of today. (1) During a phase when winds were stronger and dominantly from one direction (the south), major linear sand masses accumulated. (2) Later, when wind strengths declined, the star dunes formed. [Modern-day features known as wind streaks on the edge of the present erg (not shown), are younger than either the linear or star dunes, and show that present-day, sand-moving winds blow from the southwest.]

Fresh water lakes in the heart of the Sahara Desert

Wed, 09 Dec 2009 23:50:35 GMT

clipped by: amgumen
clipper's remarks: The reason for the apparent paradox—fresh water lakes in the heart of the desert—is that fresh water from a very large aquifer reaches the surface in the Ounianga Depression. The aquifer is large enough to keep supplying the small lakes with water despite the high evaporation rate. Mats of floating reeds also reduce the evaporation in places. The lakes form a hydrological system that is unique in the Sahara Desert.

The aquifer was charged with fresh water and the original lake evolved during the African Humid Period (about 14,800 to 5,500 years ago), when the West African summer monsoon was stronger than it is today. Associated southerly winds brought Atlantic moisture well north of modern limits, producing sufficient rainfall in the central Sahara to foster an almost complete savanna vegetation cover.

Clip Source: earthobservatory.nasa.gov

one of the largest of a series of ten mostly fresh water lakes in the Ounianga Basin in the heart of the Sahara Desert of northeastern Chad. The lakes are remnants of a single large lake, probably tens of kilometers long, that once occupied this remote area approximately 14,800 to 5,500 years ago. As the climate dried out during the subsequent millennia, the lake shrank, and large, wind-driven sand dunes invaded the original depression, dividing it into several smaller basins.

The area shown in this image is approximately 11 by 9 kilometers. The lakes’ dark surfaces are almost completely segregated by linear, orange sand dunes that stream into the depression from the northeast. The almost-year-round northeast winds and cloudless skies make for very high evaporation rates; an evaporation rate of more than 6 meters per year has been measured in one of the nearby lakes. Despite this, only one of the ten lakes is saline.

Seas of sand

Wed, 09 Dec 2009 23:38:32 GMT

clipped by: amgumen

Clip Source: earthobservatory.nasa.gov

Erg Iabes, Algeria

Posted December 3, 2009

Vast, windswept plains of sand dunes (ergs), occasionally interrupted by rocky outcrops, stretch across much of Algeria in a giant C-shape. Except for exceedingly rare oases, these seas of sand are usually empty of life, including human civilization.

This rather small erg (compared to the country’s Grand Ergs) occupies the wide gap between the El Eglab Massif to the west and the Tademaït Plateau to the northeast.

Long, linear dunes such as the ones pictured here align in the direction of the prevailing winds, and they usually form under the influence of strong winds. However, linear dunes are not the only types of dunes that are found in ergs. For example, weaker winds blowing over a linear dune in the non-prevailing wind direction may create star dunes. Barchan dunes are shaped like a crescent, with a more gradual slope on the windward side, and a steeper slope on the downwind side.

Opposing wind farms is as “socially unacceptable” as “not wearing a seatbelt”.

Wed, 09 Dec 2009 00:44:40 GMT

clipped by: amgumen

Clip Source: www.telegraph.co.uk

The Climate Change Secretary, Ed Miliband, timed his jibe impeccably last week when he said that opposing wind farms is as “socially unacceptable” as “not wearing a seatbelt”. Britain’s largest windfarm companies are pulling out of wind as fast as they can. Despite 100 per cent subsidies, the credit crunch and technical problems spell an end to Gordon Brown’s £100 billion dream of meeting our EU target to derive 35 per cent of our electricity from “renewables” by 2020.

Meanwhile the Government gives the go-ahead for three new 1,000 megawatt gas-fired power stations in Wales. Each of them will generate more than the combined average output (700 megawatts) of all the 2,400 wind turbines so far built. The days of the “great wind fantasy” will soon be over.

Man-made adjustments of the temperature

Wed, 09 Dec 2009 00:35:26 GMT

clipped by: amgumen

Clip Source: www.newsmax.com

We have discovered that the warming in New Zealand over the past 156 years was indeed man-made, but it had nothing to do with emissions of CO2 — it was created by man-made adjustments of the temperature. It’s a disgrace."

He discovered that about half of the so-called adjustments to the readings of those monitoring stations "actually created a warming trend where none existed; the other half greatly exaggerated existing warming. All the adjustments increased or even created a warming trend, with only one (Dunedin) going the other way and slightly reducing the original trend."

The "shocking truth is that the oldest readings have been cranked way down and later readings artificially lifted to give a false impression of warming, as documented below. There is nothing in the station histories to warrant these adjustments," Lott said.

for no apparent reason had its early temperatures reduced by a huge 1.3°C, creating strong warming from what was actually a mild cooling.

stunning images shot for an underwater film

Sun, 06 Dec 2009 05:32:58 GMT

clipped by: amgumen

Clip Source: www.dailymail.co.uk

Just going for a little flight: A long-beaked dolphin is caught on camera by a mini helicopter as it leaps from the water in an unspecified location in one of the images from the film

Behind the scenes: A mini helicopter hovers above a whale during the four years of filming

Health and safety?: A diver moves carefully through a sea of jellyfish

Sand-eye view: This eerie image of horseshoe crabs scuttling on a beach was part of the 500 hours of unedited footage

My, what big fins you have: A diver appears dwarfed by a sunfish in footage from the film. It took four years to create

Cuddles: A walrus with its baby in another image from the film

Cannonball!: Sea birds dive bomb the water in search of fish

Head first: An Adelie penguin diving from an iceberg in the film

Hold that pose: Two Weddell seals turn their inquisitive eyes on the camera in footage from the film

Two Californian sea lions look as though they are dancing through the reefs in the footage

house that can rotate to follow the sun

Sun, 06 Dec 2009 05:29:22 GMT

clipped by: amgumen

Clip Source: www.dailymail.co.uk

A couple in Australia have built a house that can rotate to follow the sun.

Luke and Debbie Everingham's home, in Wingham, New South Wales, can turn full circle thanks to a turntable upon which it is built.

The rooms of the octagonal building are designed to let in more light than average, and thanks to the property's unique shape, are also more spacious than usual.

All the rooms are attached to a central core of plumbings and electrical fittings around which the house can turn.

The mechanism is powered by two small electric engines no larger than that of a washing machine, and is controlled using a touch-screen panel in the living area.

The couple, who spent £400,000 designing and building the house, told how the idea was born when their neighbours were discussing their own new-build.

They had commented that if they could start again they would orientate the house 15 degrees to the north, to which Mrs Everingham replied: 'Wouldn't it be handy to have a house that could move?'

Sun Tsunami

Thu, 03 Dec 2009 15:32:19 GMT

clipped by: amgumen

Clip Source: news.nationalgeographic.com

November 19, 2009--Solar tsunamis are real, say astronomers who caught the first three-dimensional pictures of a giant wave rippling across the sun. Solar physicists first saw evidence for such waves in satellite pictures of the sun taken in 1996 (pictured), but many doubted that anything of the suggested scale could really exist.

Now the twin Solar Terrestrial Relations Observatory (STEREO) spacecraft have captured an unprecedented view of a solar tsunami triggered by a sunspot explosion in February. The massive wave rose more than 62,000 miles (100,000 kilometers) high, raced outward at 560,000 miles (901,000 kilometers) an hour, and packed as much energy as 2,400 megatons of TNT.

Green Hypocrisy

Tue, 01 Dec 2009 01:59:47 GMT

clipped by: amgumen

Clip Source: women.timesonline.co.uk

The Copenhagen summit next week will generate vast quantities of hot air. It will see 16,500 people coming in from 192 countries. That amounts to 41,000 tons of carbon dioxide, roughly the same as the carbon emissions of Morocco in 2006. Also, the organisers will lay 900 kilometres of computer cable and 50,000 square miles of carpet. More than 200,000 meals will be served and visitors will drink 200,000 cups of coffee — at least that will be organic.

Tags: green, hypocrisy

New species of chameleon discovered after snake coughs it up in front of startled scientist

Sat, 28 Nov 2009 22:31:39 GMT

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Clip Source: www.dailymail.co.uk

Discovered: The new species - Kinyongia magomberae - was discovered when it popped out of the mouth of a twig snake in front of British scientist Dr Andrew Marshall

A twig snake puffed out, which it does when it feels threatened. They can grow to a length of 3ft

A history of the world in 100 objects

Sat, 28 Nov 2009 22:25:55 GMT

clipped by: amgumen

Clip Source: www.dailymail.co.uk

The Maize God, a Mayan sculpture which shows how religion is linked to farming and fertility, and the Nef Galleon, an intricate mechanical ‘toy’ from 1500AD which demonstrates the importance that ships had for Europeans, are among the items selected for the new Radio 4 series

The gold Croesus coin - regarded as the first form of modern currency - originates from modern Turkey

The Rosetta Stone is one of the British Museum's most prized artefacts, for its significance in advancing the understanding of Egyptian hieroglyphic script

Prized: The famous Sutton Hoo helmet, an Anglo-Saxon treasure found in the Sutton Hoo burial site in Suffolk, and the and the 1.4million year old Olduvai hand axe, one of the earliest human tools

Cultural significance: The Lewis Chessmen tell the story of how chess conquered the world

Porcelain elephants from 1600AD highlight the time that the first multinational, the Dutch East India Company, controlled the porcelain supply across the world

Fossils of Martian bugs found on meteorite that landed on Earth 13,000 years ago

Sat, 28 Nov 2009 22:23:21 GMT

clipped by: amgumen

Clip Source: www.dailymail.co.uk

New evidence has made it more likely that remnants of Martian microbes were transported to Earth in a meteorite, it was revealed today.

The discovery strengthens the case for believing that worm-like structures in the meteorite are 'microfossils' of ancient Martian bugs.

Sceptics have pointed out that similar-shaped structures could be formed from non-biological processes.

Another unanswered question is whether the microfossils were the result of contamination by Earthly bacteria. This was originally ruled out by Nasa but has raised doubts in the minds of other experts.

The meteorite, catalogued as Allen Hills (ALH) 84001, crashed onto the frozen wastes of Antarctica 13,000 years ago and was recovered in 1984.

Scientists believe the rock was blasted off the surface of Mars by an asteroid or comet, reaching Earth after floating through space for around 16 million years.

It would have formed part of the planet's crust at a time billions of years ago

The amazing patterned landscapes on Mars created by extreme weather

Sat, 28 Nov 2009 22:19:19 GMT

clipped by: amgumen

Clip Source: www.dailymail.co.uk

The seasonal frost caps of Mars grow and recede each year. But the seasonal frost is composed of carbon dioxide ice (also known as dry ice), not water ice as on our planet

Lineated sand dunes dramatically lit by the Sun. By observing the changing patterns in sand dunes, scientists can learn about the interaction between the Martian surface and the atmosphere

A large outcrop of layered rock in Aureum Chaos. This area is important to aeolian geology, which is the study of landforms formed by wind

A valley in the Deuteronilus Mensae region that is dominated by glacial features. It is believed that such valleys may have originated due to intense flooding by melted water ice

Swirling trails of dust look like ink dropped into water and bluish sand dunes ripple across the surface. Other images show gigantic craters and ditches peppering the planet's geologically-diverse surface.

Wave Clouds from South Sandwich Islands

Sat, 28 Nov 2009 22:13:39 GMT

clipped by: amgumen

Clip Source: earthobservatory.nasa.gov

Even though they sit still, islands can make equally dramatic waves—in the air. This was the case in the southern Atlantic Ocean in late November 2009. The South Sandwich Islands conspired with air currents to make wave patterns in clouds.

Saunders, Montagu, and Bristol Islands, part of the South Sandwich chain, all trigger V-shaped waves that fan out toward the east. The white clouds over the dark ocean water vaguely resemble zebra stripes.

The South Sandwich Islands are of volcanic origin—Bristol and Montagu have been active during recorded history—and all the islands poke rugged summits above the ocean surface. The islands disturb the smooth flow of air, creating waves that ripple through the atmosphere downwind of the obstacles.

Spectacular views of the chaotic terrain on Mars

Sat, 07 Nov 2009 03:37:41 GMT

clipped by: amgumen

Clip Source: www.physorg.com

They cover 225 x 95 km or 21.375 sq km, an area roughly half the size of the Netherlands.

The upper portion of the image swath shows the eastern margin of Kasei Valles and the western margin of the Lunae Planum plateau and the adjoining Sacra Fossae. Kasei Valles is one of the largest outflow channels on Mars, spanning 3000 km, from the Chryse Planitia basin in the north to Echus Chasma to the south.

Sacra Fossae is a fault system that extends for more than 1000 km. It is several hundred metres deep

The images show an old 35 km-diameter impact crater in the north. The crater’s south-western rim is eroded strongly. The erosion is caused mostly by flowing water. The source of the water was located in Echus Chasma, which lies roughly 850 km to the southwest.

The crater floor and the northwestern part of the imaged region are remarkably flat and have been formed by sediments and basaltic lava flows originating from the Tharsis volcanic region.

Clip Source: www.physorg.com