diumenge, 7 d’octubre del 2018

Venture to Earth’s Most Extreme Places Through These Maps

Everest wasn’t discovered to be the highest peak on Earth until midway through the 20th century. Prior to that, a neighboring Himalayan peak known as Dhualagiri was considered the tallest as shown on this 1850 chart of the world’s mountains.

The incredible variety of landscapes on Earth has kept explorers busy for centuries. Even now that virtually all of the land has been mapped, the most extreme locations on the planet—highest, lowest, hottest, coldest and so on—have historically been difficult to identify. Some are still debated today. All of them remain intriguing and continue to beckon the most intrepid among us. This collection of maps highlights some of those extreme geographical outliers.
The distinction of the highest point on Earth is usually granted to Mount Everest, or Qomolangma as it is known in Tibetan. At 29,029 feet above sea level, it’s an extremely challenging mountain to climb, largely because the air is so thin at that elevation.
It wasn’t until around 1856 that Everest’s peak was confirmed as the highest on Earth. For the first half of the 19th century, the honor was believed to belong to another Himalayan peak, Dhualagiri. At 26,795 feet above sea level, that mountain is now recognized as the seventh highest peak.
Mount Everest reaches 29,029 feet, making it Earth’s highest point above sea level. The artist Heinrich Berann painted this profile of the mountain for National Geographic magazine in 1963.

But even today some would argue that Everest is not the highest point on Earth. It depends on where you measure from: While Everest reaches the highest point above sea level, the peak of Chimborazo, an inactive volcano in Ecuador shown in the illustration below, is farthest from the center of the Earth.
The discrepancy arises from the shape of the planet. Earth bulges around the middle giving a boost to equatorial peaks like Chimborazo. Chimborazo’s peak is 3,967 miles from Earth’s center, two miles farther than the top of Everest.
Russia’s Lake Baikal is Earth’s deepest lake, as well as the largest freshwater lake by volume. It contains nearly a quarter of the planet’s fresh surface water. Its deepest point is 5,387 feet below the surface. The lake is known for its clear water and occasional mysterious circular ice formations. This 3D view of Lake Baikal shows how steep its sides are.

If it’s the tallest mountain you’re looking for, that honor goes to Hawaii’s Mauna Kea, the highest point on the Big Island. This volcanic peak is just 13,803 feet above sea level. But the total height, from the mountain’s base on the ocean floor to its summit, is more than 33,000 feet.
Measured this way, Mauna Kea has the entire Himalaya beat, as does Alaska’s Denali. Everest comes in third by this measure because it owes a significant portion of its height to the Tibetan plateau. Everest’s base is somewhere between 13,800 and 17,000 feet above sea level (depending on what you consider to be the base): Everest only rises 15,000 feet or less from that base.
Denali, North America’s highest peak, has a base elevation of around 300 to 900 feet above sea level, giving it nearly 20,000 feet of vertical rise.
Hawaii’s Mauna Kea volcano, shown in pink at the northern end of the Big Island on this map, is just 13,803 feet above sea level. But measured from its base on the seafloor, its height is around 33,000 feet, making it the tallest mountain on Earth. This U.S. Geological Survey topographical map shows the lava flows that have erupted from Mauna Kea (light pink) and Mauna Loa (green zones) over the past 800,000 years.
On the other end of the spectrum, the lowest point on Earth is in a deep valley in the Pacific Ocean near Guam known as the Mariana Trench. The lowest spot in the trench is in an area known as the Challenger Deep, named after the ship that first sounded it in the 1870s.
It was first recorded as 26,850 feet deep, but subsequent measurements have steadily increased that depth over the years. The most recent soundings put the depth at around 35,800 feet below sea level. Compare this to the fact that most commercial airliners cruise at around 35,000 feet above sea level, and you can get an idea of how extreme this depth is. It took director James Cameron two and a half hours to descend to the bottom in a submersible vessel in 2012.

There is a long-standing debate about which of the world’s rivers is the longest. It depends on how you measure it, how you define the precise location of the mouth, and where you believe the source lies. This 1823 chart shows the Amazon as the longest, but the Nile has also been considered to be the longest. Recently new studies have suggested that the tidal canal and Para estuary should be included in the length of the Amazon, putting it at the top of the list—for now.
The lowest point on dry land is found on the shores of the Dead Sea, spanning Jordan, Israel and the Palestinian territories, at around 1,400 feet below sea level. But if we’re counting ice-covered land as dry, Antarctica would take the prize, with the valley underneath Byrd Glacier reaching a depth of more than 9,000 feet below sea level.
The Caspian Sea is considered either the world’s largest lake or, as its name suggests, the smallest sea. Its surface area is 143,200 square miles. On this comparative chart from 1855, the Caspian Sea is shown alongside the world’s major lakes as well as the Black Sea, a true sea that is just 25,000 square miles larger than the Caspian.

One record Antarctica holds without a doubt is the coldest temperature ever recorded. Temperature records are notoriously tricky because of differences in the instruments making the measurements, and whether they are recording surface temperature or air temperature. None of that matters on Antarctica—it’s insanely cold no matter how you measure it.
The coldest air temperature ever recorded was at Russia’s Vostok Research Station on the eastern side of the continent where it dropped to minus 128.6°F in 1983. In 2010, the Landsat 8 satellite recorded a surface temperature of minus 136°F on an icy ridge.
The point on Earth farthest from any ocean is the Eurasian Pole of Inaccessibility, located in China’s Gurbantünggüt Desert near the borders of Kazakhstan and Mongolia. On this 1917 map, the desert is a light brown area in the upper left quadrant.

The challenge with some of Earth’s extremes isn’t getting to them, but surviving them once you’ve arrived. This is certainly true of Death Valley, California, which has experienced the hottest temperatures ever recorded. Just as with cold temperatures, these measurements aren’t without controversy.
For many years, an air temperature of 136.4°F recorded in 1922 in El Azizia, Libya, held the world record, but in 2012 the World Meteorological Organization decided the measurement was faulty, leaving a temperature of 134.1°F recorded at Furnace Creek in Death Valley on July 10, 1913 as the hottest.
This measurement has also been called into question. Even so, Death Valley does appear to unarguably hold the hottest confirmed ground temperature record: 201°F on July 15, 1972.
Many of the hottest temperatures on Earth have been recorded in Death Valley, California. This map shows surface temperatures (in Celsius) in the area on June 30, 2013, as measured by the Landsat 8 satellite. The air temperature reached 129.2°F at the Furnace Creek Visitor’s Center in Death Valley National Park that day.
Though the locations of many of Earth’s extremes have been settled at this point, the planet will inevitably change some of them. Plate tectonics and volcanic activity may forge new highs, while erosion could create new lows. Though those things happen over thousands and millions of years, climate change could bring some new records during our lifetimes. 


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