L2

Question 1

how does matter move in the earth system

Answer 1

• Plate tectonic system
• hydrological, atmospheric systems
• Rock cycle, carbon cycle

Question 2

how does energy flow in the earth system

Answer 2

Energy flows:

• external energy flow (to and from earth)
• Internal (from Earth’s systems)

Question 3

how do life webs work in the earth system

Answer 3

Life webs:

• networks of relationships between organisms
• connects all organisms with matter cycles and energy flow

Question 4

Where does earth get energy

Answer 4

The sun is the biggest source of Earth’s Energy. Solar radiation from the sun in the form of shortwave radiation provides 99.985% of Earth’s total energy budget.

Internal energy has a relatively small contribution

Question 5

where does incoming energy go on earth

Answer 5

Incoming solar energy goes to various places:

• 6% is reflected by the atmosphere
• 20% is reflected by clouds
• 4% if reflected from earth’s surface
• 16% is absorbed by the atmosphere
• 3% is absorbed by clouds
• 51% is absorbed by land and oceans

Question 6

where does outgoing energy go

Answer 6

Out going energy:

• 23% is carried to clouds and atmosphere by latent heat in water vapour
• 15% is radiation that is absorbed by the atmosphere
• 7% is taken by conduction and rising air
• 64% is radiated to space from clouds and atmosphere
• 6% is radiated directly to space

Question 7

how does solar energy affect our planet

Answer 7

Solar energy provides the base of food chains for most ecosystems

It also drives Atmospheric circulation

Deep ocean currents carries cold water from near Greenland to the Indian and Pacific oceans

The hydrologic cycle is driven by coupling between atmospheric and oceanic circulation. The net effect of solar energy evens out surface topography by helping to cause more weathering of rocks at higher elevations

Question 8

where did the elements come from

Answer 8

~13.77 billion years ago the big bang happened.

It created Hydrogen and Helium

Li, Be and B were created from cosmic rays

C, N, O, Ne, and S were made from small/large stars

All the other elements were made from large stars, Supernovae or man made experiments

Question 9

How did earth form

Answer 9

Nucleosynthesis: Formation of elements → formation of light elements → Matter condenses → Solar nebula (big cloud of gas and dust) → Accretion (Planetismals), matter started spinning in flat circle → gravitation energy converted to heat → formed into our solar system

Condensing and Accretion (Pulling together and adding together) turned gas→dust→grains→rocks→asteroids→planets

took ~100 million years after formation of sun for matter to Accrete into planets

Question 9

what is some evidence for how earth formed

Answer 9

• Meteorites: rocks from space, record condensation and accretion
• Asteroid belt: ‘Leftovers’ between mars and Jupiter
• Impacts and craters on moon
• Study of other star systems

Question 10

why is earth hot

Answer 10

Earth was initially really hot when it formed

1. Compressional heating under gravity → Hottest at centre

Heated more:

1. Accretion - shock heating from asteroid strikes early in life
2. Radioactive decay from short lived isotopes

Question 11

why does earth have a dense core

Answer 11

High temperatures → Melting and differentiation. Earth was so hot that it was molten, allowing denser material to sink to the centre of the earth, while lighter materials floated to the surface.

Question 12

what are chondrites

Answer 12

Most primitive meteorites

Composition has same relative abundance of elements as the sun → reflects starting materials for planets

(Never part of a body large enough to undergo melting and differentiation

If you melted a chondrite meteorite the bottom layer would be a metallic liquid made from iron and nickel, then a silicate liquid layer of Si-O, finally a gas phase.

Question 13

how deep is each part of the earth

Answer 13

The Inner core is solid (5100-6378Km deep)

The Outer core is still liquid (2900-5100 km deep)

Then the Mantle is 100-2900km deep)

The crust is the top 100km

Question 14

describe our solar system

Answer 14

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

If the sun were an orange, the earth would be a grain of sand 9 meters away from it. Jupiter would be a pea 60 meters away from the sun. The nearest star would be 1600 km from the sun (from Victoria to whitehorse Yk)

Question 15

describe the terrestrial planets

Answer 15

Terrestrial (rocky) planets

• Mercury, Venus, Earth, and Mars
• closest to the sun (inner planets)
• small
• High mean density (4-5.5 g per cubic centimetre) (Rock and metallic elements)

Question 16

what are the Jovian planets

Answer 16

Jovian (gassy) planets

• Jupiter and Saturn are gas giants
• Uranus, Neptune are Ice giants
• Outer planets
• Large
• Low density (0.7-1.7 g per cubic centimetre), gaseous (He and Dihydrogen)

Question 17

what is Venus like

Answer 17

Venus:

• Rolling topography
• active volcanism
• cloudy, thick CO2 rich atmosphere
• High surface temp (450ºC)
• No water (runaway greenhouse effect)
• Analogue of early/future Earth?
• Life? (Unlikely)

Question 18

What is Mars like

Answer 18

Mars:

• Cloudy, windy
• Tremendous topography (distance from highest point to lowest point is 31 km, on earth it is 20 km)
• Volcanism
• Large core (recently identified as liquid)
• Ice caps (water and CO2)
• Liquid water? (Intermittently)
• Life? (maybe)

Question 19

What is Earth like

Answer 19

Earth:

• Water in 3 forms
• Land, sea
• Rivers, Lakes
• Continents
• Topography
• Temp gradient
• Life, including humans

Question 20

Why is earth so different from our planetary neighbours

Answer 20

Why is Earth so different?

• it has a closed water cycle, we are not losing water to space
  
  • results in a young regenerated surface
  • Enables planetary-scale life to evolve
  • has earth atmosphere exchange of elements
• Just the right distance from the sun to have water as solid, liquid, and gas
• Internal heat - has long term ongoing radioactive decay of elements
• Convection in solid rocky interior (over long periods acts as a fluid)