Dr. Sylvia Earle is an American oceanographer who has done pioneering work in the study of ocean life. During more than fifty underwater expeditions, Dr. Earle has discovered many new marine species and underwater phemonena and set important diving records. She was also among the first underwater explorers to make use of modern self-contained underwater breathing apparatus (SCUBA) gear. In 1990, Dr. Earle was named the first woman to serve as chief scientist at the National Oceanic and Atmospheric Administration (NOAA).
Thursday, August 30, 2007
Posted by Princessa at 8/30/2007 12:15:00 PM
This is Mongolia, the Saiga lives in Mongolia in the Gobi Desert
This is a picture of Gobi Desert.
Look! Is it a goat? Is it a camel? No silly! It is the Saigas! The Gobi Desert isn't empty anymore!
One of Asia’s craziest-looking large mammals is also one of its most endangered. Scientists are trying to protect the saiga antelope in Mongolia’s Gobi Desert by using high-tech GPS (Global Positioning System) collars.
They have attached the collars to eight of the antelopes. “The GPS collars will provide information on movements of saigas across this dazzling but arid landscape,” says Wildlife Conservation Society scientist Kim Berger. Then a better plan can be made to protect the antelopes.
This ungulate, or hoofed mammal, is just two feet tall (0.6 meters) at the shoulder and weighs about 50 pounds (23 kilograms). Its large, funny-looking proboscis, or nose, is a mystery. Scientists think it may warm the extremely cold winter air, or filter dust during the region’s dust storms.
Ten thousand years ago, saigas roamed from as far afield as the northern Yukon and Alaska to the United Kingdom. However, today they are found only in Asia because of changes in climate, vegetation, and habitat.
Poachers, or illegal hunters, kill them for their horns, which are used in medicine. A million of these antelopes lived on the earth just 15 years ago, but only a few thousand survive today.
“We must take immediate action to protect habitat and stop poaching for saiga horns,” said Lhagva Lkhagvasuren of the Mongolian Academy of Sciences. “Otherwise we will have only empty deserts with no saiga. Future generations will never forgive us for our carelessness.”
Posted by Princessa at 8/30/2007 11:41:00 AM
Wednesday, August 29, 2007
On this day in 1831, Michael Faraday, known for his pioneering experiments in electricity and magnetism, demonstrated the first electric transformer. Faraday discovered that electricity could be induced by changes in an electromagnetic field. This discovery is called electromagnetic induction.
Posted by Princessa at 8/29/2007 11:41:00 AM
Monday, August 27, 2007
On August 26, 1783, the physicist Jacques Charles sent up the first unmanned hydrogen-filled balloon. Leaving from the Champs de Mars in Paris, France, the balloon rose to an altitude of 3000 feet. It returned to earth in a village sixteen kilometers (ten miles) away, where terrified villagers attacked this "monster from the skies" with pickaxes and spades. One of the spectators at this event was the American ambassador to France, Benjamin Franklin.
Posted by Princessa at 8/27/2007 03:48:00 PM
Tuesday, August 21, 2007
A valley is a hollow or surface depression of the earth bounded by hills or mountains, a natural trough in the earth's surface, that slopes down to a stream, lake or the ocean, formed by water and/or ice erosion. Systems of valleys extend through plains, hills, and mountains. Rivers and streams flowing through valleys drain interior land regions to the ocean. At the bottom of many valleys is fertile soil, which makes excellent farmland. Most valleys on dry land are formed by running water of streams and rivers .The bottom of a valley is called its floor. Most floors slope downstream. Mountain valleys usually have narrow floors. The part of the floor along riverbanks is called flood plain. A valley's sides are called valley walls or valley slopes. A valley wall is the side slope of a stream or glacial valley. Rain, frost, wind and the atmosphere are loosening materials which fall into the stream and are carried away.
The form of a valley depends upon the rate at which deepening and widening goes on. V-shaped valleys are caused by forces such as erosion and rivers. Valleys are not at all formed by rivers. Valleys that are not V-shaped were formerly occupied by glaciers and are characteristically U-shaped, formed by the huge bodies of ice that moved along; they carved the valleys as they passed, carrying away giant boulders and huge amounts of debris. Valleys are usually in a U-shaped form. Narrow deep valleys are sometimes called canyons. A valley has two characteristics, one is low land, another is being formed between hills or mountains. Valleys in low areas have an average slope; in the mountains, valleys are deep and narrow.
Erosion by rivers is a main valley-forming process; other processes, such as movement of the earth's crust and glaciers, also have an important part in some cases. The rate at which a river deepens its valley depends on several factors. One factor is how fast the water is going down a channel. The water will generally reach a maximum at the point where the slope is steep. One more factor is the resistance of material through where the river channel is cutting. At the same time that a channel cuts down a valley floor, erosion carries soil and sediment down the valley slopes toward the channel. A river can remove all the material supplied easily, from the slopes and from upstream. It can continue to cut even more deeply into the bed and increase the steepness of the sides. If material can be supplied to the channel faster than it can be carried away, then the excess material accumulates on the valley floor. Steep sided valleys are often found in young mountain areas where the land is still being lifted to create mountains. Steep sided valleys occur because the uplift tends to increase the channel slope, which in turn causes the river to cut more rapidly into its bed.
Posted by Princessa at 8/21/2007 10:14:00 AM