Prelim 1 Flashcards
Where did all of the heavy elements that are found inside your body get created?
100% of the heavy elements were created inside of stars or when stars exploded
How are stars formed?
b. They started forming after the intense heat of the Big Bang cooled and cold matter began condensing into large-mass objects due to gravitational attraction. When an object’s mass becomes very large, the gravitational compression within the center of the object makes its interior hot enough to ignite thermonuclear fusion reactions.
How do we know that our sun is made from the dust of a previously exploded star?
the sun is composed of hydrogen and a range of heavier elements
Where did most of the water come from that fills the earth’s oceans?
asteroids
If you were on a boat at 10N and 160W, which ocean would you be in?
Pacific
How was our moon formed?
a mars-sized object hit the earth and the ejected material subsequently coalesced to form the moon
How quickly did life appear on earth after it cooled and the oceans filled?
remarkably quickly (500 million years)
where did the oxygen in the atmosphere come from?
photosynthesis
Life on earth began in the oceans billions of years ago. When did life on land begin?
about 550 million years ago
How long ago did a large asteroid hit the earth that caused the extinction of most dinosaurs and subsequently gave rise to large mammals dominating the earth?
about 65 million years ago
How far back can you trace the evolutionary origin of your own backbone?
the first vertebrates were fish
Does the rigid outer crust of the earth actually float on the underlying mantle?
yes, the rigid crust floats on top of the underlying mantle and acts sort of like a cork floating on water
What strong evidence led Alfred Wegener to confirm that the continents had drifted over geologic time?
fossil and mineral belts on separate modern-day continents aligned when the continents were artificially moved into a single super-continent
Why is the symmetric banding of magnetic anomalies along mid-ocean ridges considered to be strong evidence to seafloor spreading?
because magnetic anomalies are a proxy for the age of the rock and when dated, they show the crust getting symmetrically older as you move away on either side
What kind of tectonic process takes place in deep-sea trenches?
this is where ocean crust continuously sinks back into the mantle
How are continents moved around on earth over geologic time?
continents move when the tectonics plates that they are embedded in move
What is the driving mechanism for plate tectonic motion?
- mantle convection
- slab pull
are divergent boundaries only found at mid-ocean ridges?
no
Which of the following is a geographic region where ocean crust is currently colliding with ocean crust?
Aleutian Islands of Alaska