Nevada means “snowy”
Las Vegas means “the meadows” which is what it looked like 10,000 years ago.
Geo = “earth”
Logia = “study” or “science”
So, geology means “study of the earth”
Why study geology?
- Natural world
- Environmental issues
- Hazards
- Government and policy
- Planning vacations
- Buying a house
Facts about Nevada:
- Nevada’s elevation ranges from 479ft to 13,140ft.
- Nevada is the third most seismically active state in the U.S.
- Nevada is the driest state in the U.S.
Fields in Geology
| Field | Description |
|---|---|
| Hydrological & Environmental Science | Study movement, distribution, etc of water. |
| Economic | Gold, silver, lithium, etc |
| Structural | Crust movements, deformations, etc |
| Geophysics | Investigating mineral behavior and rock deformation |
| Planetary | Other planets and asteroids |
| Paleoclimate & Paleoecology | Reconstructing past environments, climate changes, and evolutionary biology using fossils |
Scientific Method
Basic research is curiosity driven, wanting to explain the “why”
Applied research is need driven, wanting to find a solution to a problem.
- Make observations, collect data
Ex: My toaster won’t toast - Develop ideas to explain observations, called a hypothesis
Ex: Maybe the outlet is broken - Come up with ways to test the hypothesis
Ex: Plug the toaster into a different outlet - Test the hypothesis, to validate or refute it
Ex: My bread toasts OR My bread still won’t toast - A hypothesis that has been tested repeatedly is called a theory
A hypothesis is an untested explanation.
A theory is a well-tested and widely accepted view.
A law is a theory that has no sensible reasons to refute it.
Origin of the Earth
Principle of Uniformitarianism
- Processes operating now also apply to the past
- “the present is the key to the past”
Meteorites tell us that the earth is just over 4,560,000,000 / 4.56 Ga years old.
We know this because of radioactive decay.
Ga = “gigaannum” = “billions of years”
The universe formed 13.8 billion years ago with the big bang and has been expanding ever since.
Hydrogen and Helium are the most common elements.
Missing information here
As the universe continues to expand, H and He collect into nebulae due to gravity.
Nebulas experience a runaway collapse and contracts into a protostar.
- Pressure and temperature increase
- Conditions become right for fusion
Stellar nucleosynthesis created elements up to Fe that can create new nebulas.
New stars may then be created from those nebulas.
The doppler effect
- The sound an ambulance siren makes as it moves towards and then away from you.
- Light does the same thing.
Two ideas if expansion will stop
- Big Chill -> keeps on expanding and cooling
- Big Crunch -> at some point gravity will take hold and pull everything back together
The milky way galaxy is 13.6 Ga old
Our solar system
- The sun has 99.8% of its mass
- 71% H, 27% He, 2% other elements
The nebular hypothesis
- As the disk cooled, some hot gases condense into solids
- Grains -> boulders -> planetesimals -> planets
- Inner and outer planets form in different way