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Australia from Space – The Blue Mountains

Landsat image of the Blue Mountains

The dramatic and dense Blue Mountains are located to the west of Sydney, Australia. This image was taken by the Landsat 7 satellite.

THE BLUE MOUNTAINS RISE to a broad plateau not far west of Sydney, Australia. In the heart of the mountains lies the Grose Valley, bounded by sheer 300-metre-high cliffs.

This dramatic landscape was sculpted by forces of erosion acting on the underlying geology; that is, characteristics of each rock type helped determine the topography.

This natural-colour satellite image was acquired by the Enhanced Thematic Mapper Plus (ETM+) instrument on the Landsat 7 satellite.

Deep green forests, dominated by eucalyptus trees, cover the landscape. The light grey buildings of Blackheath lie just to the west of the valley (lower left), and the light green orchards and pastures surrounding Berambing are visible to the northeast (upper right).

Two main types of rocks make up the Grose Valley and the immediate surroundings: a young, thin layer of volcanic rock, and a thick sequence of sedimentary rocks, laid down by wind and water several hundred million years ago. Several distinct types of shale, sandstone, and siltstone appear in the sedimentary sequence, which comprises the bedrock in most of this image.

Artist's impression of the Landsat 7 satellite

Artist's impression of the Landsat 7 satellite

The topmost layer is comprised of basalt erupted 15 to 18 million years ago from an unknown source. Most of this basalt has eroded away, but some can still be found at high points like Mount Tomah. Soils in these areas support a unique ecosystem called Tableland Basalt Forest, which appears bright green in this image.

Directly beneath the basalt are Wianamatta Group shales, followed by the Hawkesbury Sandstone—which forms the cliffs along the Sydney coast, 100 kilometres to the east. These two rock layers are softer than the basalt above and the sandstone below, so they have mostly eroded away except where protected by a cap of basalt.

Beneath the Wianamatta Group and Hawkesbury Sandstone are layers of very hard sandstone called the Narrabeen Group. These 240 million-year-old sandstones resist erosion and form the sheer cliffs that surround Grose Valley.

Softer shales and sandstones, the “Coal Measures,” underlie the Narrabeen sandstones and make up the slopes visible beneath the cliffs. Coal and oil shales in these formations have been mined extensively.

At the base of the valley is Berry Siltstone, originally deposited on an ocean floor over 260 million years ago. The Grose River flows atop this siltstone, carrying freshly eroded sand grains eastwards to the ocean.

See the full-size image of the Blue Mountains from space.

Text adapted from information issued by Robert Simmon. NASA Earth Observatory image by Jesse Allen and Robert Simmon, with Landsat data from the USGS Global Visualization Viewer. Landsat graphic courtesy NASA.

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Australia from Space: Part 3

Lake Acraman seen from space

Lake Acraman sits inside the eroded ruins of an ancient impact crater in the Gawler Ranges in South Australia. Presently about 20 kilometres wide, the original crater could have been up to 85 or 90 kilometres across. It is thought to have formed during the impact of a large meteoroid about 580 million years ago.

AFTER ANTARCTICA, AUSTRALIA IS THE DRIEST continent on Earth, and is largely covered by desert. But even the desert sometimes gets rain, as witnessed by the salt lakes spread throughout the landscape. Although usually dry, they very occasionally can receive water, often as runoff from higher ground.

These amazing images of the Australian ‘outback’were taken by Italian astronaut Paolo Nespoli during his stay aboard the International Space Station.

Lake Cadibarrawirracanna seen from space

According to Wikipedia, Lake Cadibarrawirracanna has the distinction of having the second-longest official place name in Australia. This salt lake is found within the Woomera Prohibited Area in South Australia. Woomera was once a very active rocket launch facility in the 1950s and 1960s. The name Cadibarrawirracanna means 'stars dancing on water'.

Lake Frome seen from space

Another salt lake is Lake Frome, also in South Australia. An ephemeral lake, it spends most of its life dry but sometimes fills with water. According to indigenous Australian Dreamtime mythology, the Rainbow Serpent Akurra drank all the water in the lake.

Lake Noondie seen from space

Lake Noondie, another salt lake, is located in the remote Murchison area of Western Australia.

Terrain near Lake Willis seen from space

This looks like an amazing piece of artwork, or maybe stained tissue cells under a microscope. In fact, what we see here is the dramatic red landscape near Lake Willis in Western Australia.

Red sand dunes in Western Australia, seen from space

Another apparent artwork, this time red sand dunes in outback Western Australia. Fuffy white clouds show there is some moisture in the air.

Earlier Australia from Space pictorials:

Australia from Space: Part 1

Australia from Space: Part 2

Adapted from information issued by ESA / NASA.

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Australia from Space: Part 2

Kimberley shoreline, Western Australia

The Kimberley is a large region in northern Western Australia. Bordered on the north by the Timor Sea, it is the place where the ancestors of Australia's indigenous inhabitants are thought to have landed after crossing from the Indonesian archipelago. This image shows only a small part of the Kimberley coastline.

THESE BEAUTIFUL IMAGES of the Australian coastline and islands were taken by European astronaut Paolo Nespoli from his vantage point aboard the International Space Station (ISS).

The ISS circles the globe in every 91 minutes, with different parts of our planet’s surface visible underneath each orbit as the Earth rotates.

Elizabeth Reef

Elizabeth Reef in the Tasman Sea, is a coral reef that measures about 8 kilometres long by 5.5 kilometres wide. It is located 45 kilometres from Middleton Reef (see next photo), 160 kilometres from Lord Howe Island, and a little over 500 kilometres from the coast of New South Wales. The reef, normally almost fully submerged except at low tide, has claimed a number of shipwrecks during the years, including a yacht in 2007, whose lone British sailor was winched to safety by a Royal Australian Navy helicopter.

Middleton Reef

Middleton Reef is a twin of Elizabeth Reef, located only 45 kilometres away, and around 200 kilometres from Lord Howe Island. It's almost the same size too, being just 8.9 kilometres long by 6.3 kilometres wide. Like Elizabeth Reef, Middleton is almost entirely submerged except at low tide.

King Sound, Western Australia

King Sound is a gulf in northwestern Western Australia, fed by the Fitzroy River. It has the highest tides in Australia, reaching a height of 11.4 metres at Derby, a town on the shore of the Sound. William Dampier was the first European to explore the Sound, in 1688 aboard the ship Cygnet. This image shows only a small part of the Sound, the full dimensions of which are 120 kilometres in length by 50 kilometres width.

Section of the Great Barrier Reef

The Great Barrier Reef, which stretches 2,600 kilometres along Queensland's coastline, is the world's largest reef system. It has almost 3,000 separate reefs, around 900 islands and covers an area of just under 350,000 square kilometres. This image shows only a tiny part of it.

Adapted from information issued by ESA / NASA.

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