Habitability (week 3) Flashcards
what is the habitable zone
- where liquid water can be stabilised
- terrestrial planet
- C02, water, nitrogen atmosphere
what is the faint sun paradox
- solar luminosity less 4.5 GA
- 30% less luminosity
transition from hadean earth to matured phanerozoic earth
- influx of volatile-rich chondritic material
- deep carbon storage in matured earth
what are not the limits for life
- gaseous oxygen
- a star potentially
- an atmosphere
what are the key molecules to life
CHNOPS
- carbon is the backbone
versatile
what are the four classes of macromolecules found in living cells
- nucleic acids, proteins, lipids, carbohydrates
how did these elements come about
- stellar nucleosynthesis, where fusion occured within stars to create heavier elemetns than hydrogen/helium
- when they explode/die/merge these elements are released
how do elements form minerals and molecules
cooling from a gas
equilibrium in each step needs to be reached
how were planets moons and other objects formed
- how were volatiles formed
- condensed from a hot gas
- condensed into solid ice grains in the outer solar system
- this produced 4 terrestrial planets and 4 outer gas giants
what is a volatile
- chemical elements and compounds with low boiling points
- mainly in crust or atmosphere
what is planetary accretion
- volatile rich gas planets and volatile poor rocky
earths water supply compared with other planets
- little water in comparison to its size
-icy moons such as titan and callisto have a much higher water ratio
where do earths volatiles come from if not water
- asteroids, c-type, M type and s type
- they contain amino acids and other organic compounds
- PANSPERMIA THEORY THAT ASTROID IMPACTS BROUGHT LIFE TO EARTH
-PROVIDE US WITH METEORITES
EASY classification of meteorites
-stony
-stony iron
-iron
MEDIUM classification of meteorites
stony can be split into chondrites (undifferentiated, silicates, metals/sulphides) and achondrites (experienced igneous processing)
