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Science Test

Earth Unit

What substances are in earth's second atmosphere? Water vapor, nitrogen, and carbon dioxide
What substances are in earth's first atmosphere? Helium, and hydrogen
What substance do living organisms give to the atmosphere? Oxygen
What are the earliest life forms similar to? Bacteria
What is a comet? A ball of dust and ice that orbits the sun
What galaxy is the earth in? The Milky Way Galaxy
What galaxy is closest to earth? (closest other galaxy) Andromeda
What star is closest to earth other than the sun? Proxima Centuri (4.2 light years away)
What is the distance that a star travels in a year? Light Year
When did the Precambrian begin? 4.6 billion years ago
When did accretion begin? 4.6 billion years ago
When did Cambrian begin? 544 million BP
What is accretion? The process of forming the earth through gravity causing matter to come together
What is molten? Melted; when something is in liquid form
What forms when the surface rock cools? The crust
What sinks to the center of the earth forming the core? The heaviest metals
What transforms the planet to become a molten planet? Heat from accretion
What causes matter to come together Gravity
When did Precambrian end? 544 million BP
When did Pangaea occur? 150,000,000 BP
When was the last ice age advance? 17,000 BP
How long did accretion last? 100,000,000 years Began 4.6 billion years ago
What is the age of the earth? 4.6 billion years old
Why is the interior of the earth hot? 1)The friction in the core 2)Heat from accretion trapped by crust 3) The matter inside earth's core
What forms the crust? The cooled rock on earth's surface
Why are iron and nickel the most predominant elements of the core? The most dense
Created by: kaylashay34