Backround / Introductory Information (Week 1 full)

Question 1

When was the evidence for early life on earth discovered

Answer 1

1993- from 3.5 Ga

Question 2

What is the rare earth Hypothesis

Answer 2

The earth is very unique, with very distinct features
-magnetic field
-location in the solar system
-large moon
-plate tectonics

Question 3

What is the goldilocks zone

Answer 3

• where it is possible for water to exist
• water has been present for estimated 4.3 Ma years ago- discovered from zircon grains with oxygen isotopes in them

Question 4

When was the hadean (when earth formed)

Answer 4

4.6 to 4 Ga

Question 5

What is planetary differentiation

Answer 5

• all rocky planets have a core, mantle and a crust
  the denser elements sink to the surface of the earth
  the exterior is more silica rich compared to the iron rich centre
• the lithosphere is composed of the crust and uppermost solid mantle

Question 6

Why is it important that earth has a magnetic field?

Answer 6

Stops the water on earth being stripped away
protects earth from radiation and charged particles
more protection from UV A and B Radiation
prevents the ozone being stripped away too
allows living organisms to use such as butterlflies

Question 7

What is a geodynamo

Answer 7

• rapid movement of liquid iron in earths outer core
• due to temp and comp differences between inner and outer core
  -enhanced by earths convection currents
• polarity reversals occur every 100,000 to several Ma years
• takes a few thousand years to switch

Question 8

What is the evidence for a magnetic field

Answer 8

• magnetite magnatisation- remanant in ferromagnetic minerals such as this
• earliest evidence is found in 3.45 Ga rocks from Australia
• lack of data before this

Question 9

How did the core of earth solidify

Answer 9

• releases additional heat energy
• which helps to keep dipole of the magnetic field
  -gradual decay of this dipole occured 500 Ma at the end of the phanerozoic
  -the geodynamo collapses almost as the inner core begins to crystallize

Question 10

How was the moon formed

Answer 10

• 4.5 GA Theia smashed into earth (maes sized)
• happened 60 million years after earth was formed
• mantle was melted and the crust on the surface was stripped away
• evidence included identical oxygen isotope fingerprints to rocks on earth

Question 11

How does the moon affect the world that we live in

Answer 11

• affects the tidal patterns we can observe
• created tidal pool habitats which may have allowed the origin of life
• research to oppose other theories, where the moon powers the geodynamo in the outer core.

Question 12

How do plate tectonics help to sustain life

Answer 12

• allows the maintenance of geological carbonate weathering cycles which regulate earths climate
• all of this contributes to this hypothesis

Question 13

what is the n=1 problem

Answer 13

• life on earth is an unreliable source to compare to for finding life
• this is because the life forms living on earth are only representative of a tiny part of the universe

Question 14

how much of space has been discovered by kepler

Answer 14

• 3000 light years (0.25 percent of sky)