Wednesday, September 28, 2011

Crews scale Washington Monument checking for earthquake damage

A team of engineers recently rappelled down the sides of the Washington Monument looking for damage caused by a rare earthquake that hit the East Coast in August. Crews exited the iconic monument from windows at the 500-foot level and scaled to the top to do a very close visual inspection. They were conducting an inventory of cracks sustained during the earthquake to determine whether those cracks could, in the next couple of years, grow.

The heaviest damage appears to be concentrated at the very top of the monument, in what is called the pyramidion, where large cracks of up to 1-1/4 inch wide developed through stone and mortar joints, according to officials with the National Mall and Memorial Parks. Daylight is visible through some of the cracks, and rain water has gotten into the monument, which could cause further damage.

The difficult-access rappelling team scaled the outside of the structure to get a closer look. They installed climbing ropes and safety lines on all four sides, then clipped onto those lines. They climbed up the pyramidion and then descended the length of the monument looking for exterior damage.

The Washington Monument, built between 1848 and 1884, is 555 feet tall. Its walls, 15-feet thick at the base and 18-inches at the top, are composed primarily of white marble blocks, according to the Park Service.

On a journey to Washington, D.C. with Discovery Student Adventures, which famous landmark would you most like to explore?

Friday, September 16, 2011

Great white shark numbers dwindling

The world’s most feared fish may have something to fear itself: Its own demise. Far fewer white sharks are cruising the waters off California than previously thought, according to a new study. Counting the great white sharks was a hands-on activity. Researchers went out into the Pacific Ocean in small boats to places where great white sharks congregate, and lured the massive predators into photo range using a seal-shaped decoy on a fishing line.

From 321 photographs of the uniquely jagged edges of the sharks' dorsal fins, researchers identified 131 individual sharks. From these data, they used statistical methods to estimate that there are 219 great white sharks in the region.

The study, published in the journal Biology Letters, is the first rigorous scientific estimate of white shark numbers in the northeast Pacific Ocean, and represents one of the best estimates among the world's three known white-shark populations.

Great white sharks also live in the waters around Australia and New Zealand, and off the coast of South Africa.

Shark species around the globe have suffered steep declines in recent years. As many as one-third of the world's sharks and other cartilaginous fishes are threatened, and shark numbers along the United States eastern seaboard have plummeted, some species by as much as 90 percent. Great white sharks are classified as "vulnerable" by the International Union for the Conservation of Nature, but relatively little is known about the elusive species.

Is enough being done to protect the great white shark population?

Monday, September 12, 2011

The world’s most spectacular vistas

It’s long been said the beauty is in the eye of the beholder. What’s stunning to one person may lack significant appeal to another. That may be, but when it comes to spectacular global destinations, it’s hard imagine anybody could deny the beauty of these jaw-dropping vistas.

Milford Sound

The Maori attribute the creation of the New Zealand fjords, such as Milford Sound, to Tute Rakiwhanoa, who cut the steep-sided valleys with his adze. What other explanation could there be for these spectacularly steep, sheer cliffs that rise nearly vertically from the ocean?


Also known as Ayers Rock, Uluru is a large rock formation in the National Park Uluru-Kata Tjuta in the Northern Territory of Australia. Uluru is sacred to the AŠĻČangu, the Aboriginal people of the area. The area around the formation is home to a plethora of springs, waterholes, rock caves and ancient paintings.

The Dolomites

Swiss architect Le Corbusier called Italy's Dolomites les plus belle architectures du monde (the most beautiful architectures on Earth); indeed, the Italian mountain range speaks to the power of nature. The Dolomites comprise many types of rock, some of which eroded spectacularly, leaving seemingly delicate pinnacles, some of which formed tightly compact peaks and some of which formed from cooling lava.

Grand Canyon

The Grand Canyon can easily overwhelm our imaginations with its daunting size: A mile deep, 277 river miles long and 18 miles across at its widest. But it can immediately deliver serenity with its solid magnificence; it is a powerful landscape at any time of the day, but most inspiring at sunset and sunrise when the canyon walls color and fade.

Cliff of Moher

As if shot from the floor of the Atlantic Ocean, the massive Cliffs of Moher make the edge of Ireland appear to have been sheared off by giants a long time ago. One of the country's most popular attractions, the Cliffs of Moher attract a million visitors each year and provide a home for millions of nesting sea birds.

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