1. Planet Earth

Question 1

What shape is the Earth? Describe it

Answer 1

• Oblate spheroid
• A sphere like but not perfectly spherical body (slight squish; flattens at poles, bulges at equator)

Question 2

What are the layers of the Earth?

Answer 2

Crust
Mantle
Outer Core
Inner Core

Question 3

What are the features of the Crust?

Answer 3

• 55°c
• 0-70km
• rock, granite, basalt

Question 4

What are the features of the Mantle?

Answer 4

• 650-800°c
• 2900km
• rock, mg, al, silver
• thick, almost solid liquid

Question 5

What are the features of the Outer Core?

Answer 5

• 5000°c
• 2200km
• liquid rock/iron

Question 6

What are the features of the Inner Core?

Answer 6

• 5500°c
• 1220km
• iron
• hot dense ball, pressure of 3.6mil atmospheres

Question 7

What is Longitude?

Answer 7

Vertical lines telling us how far E or W a point is relevant to the prime meridian

Question 8

What is Latitude?

Answer 8

Parallel lines telling us how far N or S a point is, relevant to the equator

Question 9

What is the Prime Meridian?

Answer 9

A line (goes through Greenwich) that divides the Earth into E and W hemispheres
Time zones are determined by how far E or W you are

Question 10

Where is the Tropic of Cancer?

Answer 10

Northern Hemisphere
23.5°N

Question 11

Where is the Tropic of Capricorn?

Answer 11

Southern Hemisphere
23.5°S

Question 12

What is the tilt of the Earth?

Answer 12

23.5°

Question 13

Why do stars twinkle?

Answer 13

As light is passed through the layers in the atmosphere it is bent and distorted by the varying temperatures and air densities
These seeing conditions make the stars ‘twinkle’

Question 14

What does atmospheric scintillation mean?

Answer 14

Stars Twinklings
- The quick changes in the brightness of a star produced by atmospheric effects

Question 15

Why don’t planets twinkle?

Answer 15

Stars are so much further away & are concentrated points of light, which are more easily disrupted by the Earth’s atmosphere

Question 16

What is the atmosphere like above the equator?

Answer 16

There is a low pressure zone called the intertropical convergance zone - a wide belt of trade winds and rising air
Areas above/next to the equator have frequent cloudiness and thunderstorms

Question 17

When is the sun directly above the Tropics?

Answer 17

Cancer - Noon, June 21st
Capricorn - Noon, December 21st

Question 18

When do the equinoxes occur?

Answer 18

When the sun is directly over the equator

Question 19

When is the arctic circle dark?

Answer 19

The Winter Solstice - sun won’t be able to be seen at all
AC = Latitude 66.5°N

Question 20

How can the Earth’s atmosphere affect observations?

Answer 20

• Temperature changes
• Air currents
• Weather fronts
• Dust particles
  (all can affect the transparency of sky)
• Blue sky - obs can only be done at night

Question 21

Why does the sky appear blue?

Answer 21

Light is scattered by oxygen and nitrogen molecules in our atmosphere, most scattering occurs at the shortest wavelengths (blue) so the sky is predominantly blue

Question 22

What are the layers of the Earth’s atmosphere?

Answer 22

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere
• Exosphere