1.1 Earth

Question 1

What is the earths diameter

Answer 1

13,000km

Question 2

What shape is earth!

Answer 2

Oblate Spheroid

Question 3

What features distinguish us from other planets

Answer 3

Atmosphere

Liquid water

Life

Question 4

How do we know the earth is not flat?

Answer 4

Ships disappear below horizon

Satellites orbit Earth which would be impossible if it were flat

Curvature of the earths shadow during a partial lunar eclipse

Question 5

What’s latitude yo

Answer 5

The angle between a point on the earths surface, how far north or south you are of the equator

Question 6

How much is the earth tilted by

Answer 6

66.5 to the plane on which it orbits the sun (ecliptic)

Question 7

What are the tropics

Answer 7

The Tropic of Cancer is 23.5degrees north

Tropic of Capricorn is 23.5degree south

Question 8

What’s longitude

Answer 8

Angular displacement of how war east or west you are of the prime meridian

Question 9

What’s the zenith

Answer 9

Point directly above the observer

Question 10

What’s the horizon

Answer 10

Imaginary plane that meets the observer at a tangent to the earths surface - where sky meets seas/land

Question 11

What’s the main source of light pollution?

Answer 11

Commercials and sports lights

Street lamps

Domestic and industrial security lamps

Lights in car parks and shopping centre

Question 12

How did Eratosthenes estimate circumference of earth?

Answer 12

He was in Syene near the Tropic of Cancer and saw at noon a stick had no shadow , he then at the same time next year in Alexandria that was a 7 degree shadow he knew this was 1/50 of a circle and that the distance between the 2 places was 790km and so used simple geometry to sea earth was 50 times this - got 39,500km which was within 5% accuracy

Question 13

What’s the composition of the earths atmosphere

Answer 13

78% nitrogen
21% oxygen 
1% argon 
1% water vapour average
0.04% carbon dioxide

Question 14

What’s the kármán line?

Answer 14

The boundary for the atmosphere and space which is 100km

Question 15

What are the benefits of the atmosphere

Answer 15

Regulates temperature

Absorbs uv Ray’s that can cause skin cancer

Absorbs X-rays and gamma rays

Allow liquid water

Provides oxygen to breath

Question 16

What’s is a draw back of earths atmosphere?

Answer 16

The refraction of light as it passes through our turbulent atmosphere causing stars to twinkle and restricting resolution

The selective scattering of shorter blue wavelengths making sky blue so we can’t observe in day

Absorption of most electro magnetic radical ion like uv, gamma and X-rays requiring earth orbiting satellites instead

Question 17

What’s are the 2 Windows electromagnetic radiation can reach the ground

Answer 17

Optical window

Radio window

Question 18

What effect does the atmosphere have on long electromagnetic radiation (EMR)

Answer 18

There are reflected back into space by electrons in ionosphere

Question 19

What does the atmosphere do the shorter EMR waves

Answer 19

(Microwaves) are absorbed by water vapour and oxygen

Question 20

What does the atmosphere do to infrared radiation

Answer 20

It’s absorbed by water vapour

Carbon dioxide and methane

Question 21

What does the atmosphere do to uv Ray’s

Answer 21

Absorbed by ozone(O3) and shorter wavelengths by O2

Question 22

What’s does the atmosphere do to X-rays and gamma rays

Answer 22

Absorb them by oxygen and nitrogen so radiation loses energy and fails to penetrate much of upper atmosphere

Question 23

What are the 2 types of telescope?

Answer 23

Refractor- convex lens

Reflector- curved mirror

Both collect light and bring it to a focus

Question 24

What’s the objective of a telescope?

Answer 24

This diameter of the lens

Question 25

What’s selective scattering?

Answer 25

When The atmosphere is better at scattering certain wavelengths than others
Scattering is a rapid process whereby light is actually absorbed by a particle and then quickly emitted in another direction.

Question 26

What are the advantages of telescopes with a bigger objective

Answer 26

They collect more light

Higher resolution in proportion to diameter

Question 27

How do you work out how to compAre how many times higher the resolution is of two telescopes ?

Answer 27

Example

A 10 metre telescope collect 25 times more light Than a 2metre telescope 25=5squared so it has 5 times higher resolution

Square root the amount of times it collects more light= how many times higher the resolution is

Question 28

What’s the most popular lens for s telescope?

Answer 28

A reflector as mirrors can be made to a higher precision

Question 29

What things should you consider when choosing an observing site!

Answer 29

Atmosphere
Cloud cover, air turbulence, Sky brightness, water vapour content

Geographical location
Access, utilities, ground stability

Question 30

What’s are the advantages of space telescopes?

Answer 30

There’s no atmosphere to blur images or reduce resolution

No light pollution

No adverse weather problems

No day or night can observe all the time

Can detect other wavelengths like X-rays or IR waves

Question 31

What are the problems with space telescopes?

Answer 31

Reduced life time

Difficult or impossible to maintain or repair

Damaged by solar wind or radiation

More expensive to land into orbit and build

Question 32

What’s the inner van allen belt like

Answer 32

Made of high energy proton between 0.1 and 1.5 earth radii can be hazards to atronauts and satellites

Question 33

What’s the outer van Allen belt like

Answer 33

Mainly electron altitude of between 3-10 earth radii

Question 34

What’s the perihelion

Answer 34

When we are closest to the sun in January

Question 35

What’s aphelion

Answer 35

When we are furthest from the sun in July