Earth and the Solar System

Question 1

What is the Earth System?

Answer 1

a dynamic body with many separate, interacting parts/spheres

Question 2

What are the characteristics of the Geosphere?

Answer 2

solid rock and surface features
6400km to the centre
Lithosphere about 100km thick

Question 3

What percentage of the surface does the hydrosphere occupy and what is its breakdown?

Answer 3

71% of surface

97% ocean, 3% freshwater

Question 4

What are the characteristics of the atmosphere?

Answer 4

thin, gaseous envelope, 90% within 16 km of surface

integral to planet (weather, climate) and biosphere (breathing, UV protection, heat)

Question 5

What are the characteristics of the Biosphere?

Answer 5

all life, contained near surface

organisms alter the makeup and nature of all spheres

Question 6

what are some examples of natural resources in the earth system?

Answer 6

metals
water
food
materials

Question 7

What are some examples of hazards in the earth system?

Answer 7

earthquakes
eruptions
flooding
forest fires

Question 8

What are some examples of matter moving?

Answer 8

plate tectonic system
hydrological, atmospheric cycles
rock cycle, carbon cycle

Question 9

What are some examples of energy flows?

Answer 9

external

internal

Question 10

What are life webs?

Answer 10

network of relationships

connect all organisms with matter cycles and energy flows

Question 11

Which is the thickest of the earths spheres?

Answer 11

Geosphere

around 6400km thick

Question 12

What is the biggest source of the earth’s energy?

Answer 12

sun
solar energy (shortwave radiation) contributes 99.985% of earths total energy budget

Question 13

Where is solar energy more concentrated?

Answer 13

in the equatorial regions

Question 14

Solar energy

Answer 14

powers processes acting on earths surface which are crucial for life eg photosynthesis
affects atmospheric circulation, ocean circulation, hydrologic cycle
the net effect of solar energy evens out surface topography

Question 15

Where does earths internal energy come from?

Answer 15

very hot core

radioactivity in the mantle

Question 16

What is nucleosynthesis?

Answer 16

the formation of elements by various means

eg. big bang, large stars, supernovae, cosmic rays, small stars

Question 17

What are the steps from gas to planet?

Answer 17

gas
dust
grains
rocks
asteroids
planets

Question 18

What are condensing and accretion?

Answer 18

pulling together and adding together

Question 19

What is the evidence for condensing and accretion?

Answer 19

Meteorites: rocks from space, record condensation / accretion
Asteroid belt: ‘leftovers’ between Mars and Jupiter
Impacts & craters on Moon
Study of other star systems

Question 20

Earth was initially hot. Where was it hottest? Why?

Answer 20

compressional heating under gravity -> hottest at centre

Question 21

What heated earth more?

Answer 21

Accretion – shock heating

Radioactive decay – short lived isotopes

Question 22

What did high earth temperatures lead to?

Answer 22

melting and differentiation

Question 23

What are chondrites?

Answer 23

the most primitive meteorites

Question 24

What is the composition of a chondrite? What does it reflect?

Answer 24

same relative abundance of elements as the Sun

reflects ‘starting’ materials for planets

this means it was never part of a body large enough to undergo melting & differentiation

Question 25

Early earth was a ...... ocean.

Answer 25

magma

Question 26

What is a good way to visualise the scale of the solar system?

Answer 26

If the Sun were an orange: earth would be a grain of sand 9 metres away Jupiter would be a pea 60 metres away the nearest star would be 1600km away

Question 27

What are the terrestrial (rocky) planets?

Answer 27

``` Mercury, Venus, Earth, Mars Closest to the sun (inner planets) Small High mean density (4-5.5 g/cm³) rock and metallic elements ```

Question 28

What are the jovian (gassy) planets

Answer 28

``` Jupiter and Saturn (gas giants) Uranus and Neptune (ice giants) Outer planets Large Low density (0.7-1.7 g/cm³) gaseous (He, H₂) ```

Question 29

Where is the frost line?

Answer 29

between the terrestrial and jovian planets

Question 30

What are Venus' characteristics?

Answer 30

``` Rolling topography Active volcanism Cloudy, thick CO2-rich atmosphere High surface temp (450 °C) No water (runaway greenhouse effect) Analogue of early/future Earth? ```

Question 31

What are Mars' characteristics?

Answer 31

``` Cold, windy Tremendous topography Volcanism Small core Ice caps (water & CO2)- Liquid water? Life? (maybe) ```

Question 32

What are Earth's characteristics?

Answer 32

``` Water in 3 forms Land, sea Rivers, lakes Continents Topography Temp gradient Life, including Humans ```

Question 33

Why is earth unique?

Answer 33

has a water cycle

Question 34

Why is Earth so different?

Answer 34

``` Just right distance from Sun to have water as solid, liquid, and gas Water cycle (closed system) - Results in a young regenerated surface and Enables planetary-scale life to evolve (earth-atmosphere exchange of elements) Internal heat– long-term (ongoing) radioactive decay of elements Convection (movement) in solid rocky interior (over long periods acts as a fluid) ```