oceanography midterm

oceanography midterm - Week 1: Earths Early Years How old...

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Week 1: Earth’s Early Years How old is the Universe? Universe: 14 billion years old How old is the Earth? Earth: 4.6 billion years, about 5 Billion years old. How do we know the age of the Earth? Density stratification Where do elements lighter than iron come from? Formed by stars. Where do elements heavier than iron come from? Formed by Supernovas when the nuclear forces holding apart individual atomic nuclei are overcome and from heavy atoms. What are the processes involved? Nuclear Fusion- The process in which light atoms such as those of hydrogen and deuterium combine and form heavier atoms, releasing a great amount of energy, that primarily manifests itself in the form of heat. What do I mean by nuclear stability? After a star begins fusion it is said to be in a state of nuclear stability. It does not expand or shrink at that time. It burns its hydrogen fuel at a steady rate, converting hydrogen to atoms as heavy as carbon or oxygen. How does this relate to life on Earth? All life comes from stars. The elements formed by these processes create life on earth. What is meant by density stratification? Earth has more dense materials in the middle, Earth was homogenous at first, but became density stratified. Gravity pulled most of the iron and nickel inward to form the planet’s core, causing gravitational energy and heating earth even more. Lighter minerals, on the other hand, rose toward the surface, forming Earth’s crust. How does this relate to the oceans? Oceans formed due to a constant cycle of rain and evaporation, which eventually lead to the cooling of the earth’s crust and the ability for an ocean to form. Minerals remain on earth’s crust after rain evaporates. What are the densities of material in each zone of the Earth? Core: 13g/cm3 Lower Mantle: 4.5 g/cm3, Upper Mantle: 3.3 g/cm3, Lithosphere: Continental Crust: 2.7 g/cm3, Oceanic Crust: 2.9 g/cm3; Ocean Water: 1 g/cm3. How were the atmosphere and ocean formed on Earth? The atmosphere was formed when the gasses that were trapped inside the forming planet burped to the surface to form a second atmosphere. Oceans formed due to a constant cycle of rain and evaporation thanks to the clouds, which eventually lead to the cooling of the earth’s crust and the ability for an ocean to form. Minerals remained on earth’s crust after rain evaporated Where did the material come from? The material came from inside of the earth along with the suggestion that a barrage of icy comets or asteroids collided with earth adding to the accumulating mass of water. What process was involved? Out-gassing: the volcanic venting of volatile substances. What do we know about the origin and early evolution of life on Earth? Life most likely formed in the oceans. Carbon (organic) compounds brought to earth by comets and asteroids.
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oceanography midterm - Week 1: Earths Early Years How old...

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