How long ago did the solar system start to form
4.5 billion years
How did earth become the size it is today
Collisions with asteroids and stuff
What can we learn about early earth through recreating asteroid impacts
- can simulate what it looked like way back
- huge impacts + craters formed
How did the core of the earth start to generate heat
- huge impact released a loooot of heat
- Fe + Ni melted and moved to core (generated more heat)
- melted magma on surface (literally hell on earth)
- within first 40 million years
How was the magnetic field created
Rotating ball of Fe
Role of magnetic field
Protects us from the sun
Holds air in + saves atmosphere
How did earth reach its present mass
More collisions (meteorites)
How old is earth
4.5 billion years old
How do we know how old earth is
Meteorites (radioactive dating) (formed same time as earth)
Theories to explain how water formed on earth (3)
- asteroids comets
- –looking to see the ratio of H2O and HDO (2x heavy hydrogen) - so far Kuiper belt comets have different proportions but maybe the asteroid belt
- 3.9 billion years ago earth cooled + formed crush over mantle, warm liquid covered it (water)
- water from volcanoes (steam condensed from cooling earth) (steam from where?)
How might earth have been seeded with the building blocks of life
- comets from asteroid belt
- asteroids - have amino acids (organic compound)
Composition of earth’s early atmosphere
-CO2
-H2O (g)
-N2 (a little)
NO OXYGEN
What form was the earliest life
- 3.7-3.9 billion years ago
- primordial soup of amino acids
- bacteria (single celled in oceans)
What is the significance of extremophiles in understanding the origins of life?
- organism that can live in extreme environments
- proved that life evolved at high temperatures
- thermofiles
Where do we find extremophiles today?
- live at 230F
- bubbling lakes at Yellowstone
- prove that life could’ve survived and adapted on early earth
What was earth’s earliest structured life? What process evolved this organism?
- Cyanobacteria (blue-green algae)
- photosynthesis
- fed O2 into air
What change in earth allowed complex life to form
- Cyanobacteria (photosynthesis)
- Oxygen is here now!
- LAND!!!
How are humans actions possibly returning earth to its origins
- fossil fuels are too used
- climate change
- population explosion
What are cryospheres? What is their role in regulating the planet?
North + south poles
Regulate climate + water levels
How is earth’s water driving global temperatures
Ice melts = water absorbs light = planet heats = ice melts
Where is the majority of earth’s freshwater stored?
70% in Antarctica
How soon might the North Pole be free of ice in the summer?
40-60 years
If all the glaciers melt, how much could water levels rise?
3ft (that’s bad)
Why is earth considered to be nearing old age
- sun gets brighter + hotter
- all CO2 gone (?)
