Exam 1 part 2 Flashcards
Study for the first exam
How did the planet form?
The accept hypothesis is the nebula hypothesis, where a cloud called the solar nebula began to contract due to gravity about 5 billion years ago.
How old is the universe?
14 billion years ago
How old is our solar system?
Only 5 billion years old.
What was the nebula like?
It’s believed that it was a flat disk with a protosun/presun in the middle of it, the larger planets formed from rocky substances and the outer planets came from fragments of ice.
How did the structure of the earth form?
The metals sank down to the earth, the molten rock made the three sections of the earth’s interior, the atmosphere evolved from gases that were released from volcanoes.
The the earth a very hot or cool planet in the beginning?
Very hot
Who proposed the first hypothesis on continental drift and when?
Alfred Wegener, 1915
What was the continental drift hypothesis?
That the continents drifted apart to present day positions 200 million years ago
What 4 pieces of evidence was used to support wegner’s hypothesis?
1) Fit of the continents
2) Fossil evidence
3) Rock type and structural similarities
4) Paleocimatic evidence
What were the 3 objections to the continental drift hypothesis?
1) Lack of mechanism for moving continents
2) Wrong suggestion that continents break through ocean crust
3) strong opposition from all areas of the scientific community.
When was the seafloor spreading hypothesis proposed and by who?
1960s, by Harry Hess
How was the seafloor spreading discovered?
Through sonar waves, sound goes down and comes back up to the ship, the longer it takes the deeper the floor.
Where is seafloor generated and where is it destroyed?
Created at the ridges and destroyed by the trenches.
What does the lithosphere consist of?
The crust and the upper mantle
What are the 7 major lithosphere plates?
They are the 7 tectonic plates
In what ways are the tectonic plates always moving?
They are constantly moving and changing in both size and shape.
About how far does a tectonic plate move a year?
About 5 centimeters/2 inches.
What are the three types of plate boundaries?
1) Divergent (Separating, constructive, new material.)
2) Convergent (Smash together, destructive)
3) Transform (Sliding, neither creates or destroys)
Each plate is bounded by?
A combination of the three types of plate boundaries
Is it possible to have new plate boundaries?
Yes, new boundaries can be created in response to changing forces.