Dinosaur Extinction Essay

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Jay Crisfield 5/26/09 Period 8 Mrs. Stelmach Dinosaur Extinction Before the dawn of human life on planet Earth, there was a massive population of giant lizard-like creatures called Dinosaurs. They lived and roamed the earth for over millions of years, and they lived in dominance. All other life forms during this time could do nothing against the power of the dinosaurs. However, they did eventually fall to something. Scientists have theories that one or a few meteors hit the Earth, but they cannot be sure due to the lack of evidence on the matter. The element, Iridium, plays a key role as vital evidence in these theories. The main theory to the extinction of dinosaurs is called the Alvarez hypothesis, first created by Luis and Walter Alvarez in 1980. This hypothesis states that the mass extinction of life on Earth sixty-five million years ago was due to one big meteor colliding with the Earth. The team of scientists, led by Walter Alvarez and his son Luis, went to the Yucatan Peninsula, where proof of a giant meteor strike is present. When the team arrived, they noticed a large abundance of iridium located in the rock, right at the K-T boundary. This is significant because the K-T boundary was created right at the time when scientists believe the meteor hit the Earth. The 77th element on the periodic table, Iridium is a very hard, silver, brittle member of the transition metals. Iridium is one of the rarest elements in the Earth’s crust, and only has two stable isotopes. Iridium is often mistaken for platinum, however, Iridium is much more corrosive and dense. Due to its extremely high melting point, iridium is very hard to work with. Iridium is thought to be an extra-terrestrial element due to its high concentration in meteorites. One theory says that when Earth was forming in its molten stage, many meteorites hit the Earth, bringing

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