Earth Science Essay

884 Words May 29th, 2013 4 Pages
1. Summarize advances over time in determining the age of the Earth, including the importance of the discovery or radioactivity.
Herodotus counted layers of earth near the Nile River in 450 B.C.E. The Bible was used in the Middle Ages to compute the age of the Earth. The 18th and 19th centuries brought a more scientific look into determining the age of the Earth by studying the salinities of the oceans, the rates of sedimentation, and models of cooling of different materials in order to calculate the Earth’s age. In 1862, William Thompson calculated the Earth’s age to be 98 million years and recounted that age to determine that it was actually between 20 and 40 million years old. He used a very thorough method and ended up being wrong on
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Gravity and centripetal force are fighting against each other to maintain celestial bodies in an orbit around the Sun. The 1% of the mass in our Solar System that didn’t get sucked into the Sun is what makes up our planets, asteroids, and moons. The centripetal force acting on the planets aligns them with the Sun’s equator and creates the mostly flat orbit of the Solar System.

3. Alfred Wegener was a polar explorer and visionary. Describe how his early work was viewed with skepticism and how ultimately his theory on continental drift was proven. What kinds of evidence did Wegener rely on to substantiate his continental drift hypotheses (Pangaea)?
He was viewed as a meteorologist and not a geologist. With no real geological knowledge, he formulated the continental drift theory was due to tidal pull from the Sun or centrifugal force. Because scientists of the time couldn’t believe that continents could float through rock as if it were liquid. We now know that due to convection that we see through seismic tomography that the Earth is a kind of liquid on which the lithosphere is floating. His basis was partly due to the edges of the continents fit together as a puzzle. Also, rocks, plants, and animals that were spread across the globe must have started together because a rock didn’t swim to its new location.
4. Explain how seismic tomography has been used to show what is actually happening on Earth. Include in your answer…

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