Chapter 13 - Space

Question 1

What is the order of the eight planets from the sun outwards ?

Answer 1

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

Question 2

Why do all the planets orbit the sun ?

Answer 2

They travel on the same plane in the same direction as a result of the gravitational force of the sun

Question 3

What are artificial satellites ?

Answer 3

Objects put into space by humans

Question 4

What are artificial satellites used for ?

Answer 4

• communications
• earth observation
• astronomy
• weather monitoring

Question 5

How are stars formed ?

Answer 5

• Clouds of hydrogen gas and dust come together
• due to gravity
• this then changes to thermal energy and creates a protostar

Question 6

How do we tell that the sun contains mostly hydrogen and helium ?

Answer 6

• use a solar absorption spectrum

- the wavelengths of hydrogen and helium will have the most black lines

Question 7

How is the suns energy supplied ?

Answer 7

by the fusion of hydrogen into helium

Question 8

Where and how are all naturally occurring elements formed ?

Answer 8

They are all made (except hydrogen) by nuclear fusion in the stars

Question 9

Recall the stages of the life cycle of stars

Answer 9

• protostar
• main sequence
• red giant
• white dwarf
• black dwarf

Question 10

Why is a star stable during the main sequence stage of it’s life ?

Answer 10

The outward force of thermal expansion is balanced by the inward force of gravity

Question 11

What do more massive stars become after the main sequence ?

Answer 11

Red supergiants

Question 12

What happens to massive stars when they are supergiants ?

Answer 12

There is an explosion in which the outer layers are ejected

Question 13

What do you call the explosion of a supergiant and how bright does it shine ?

Answer 13

A supernova and the brightness of 10 billion suns

Question 14

What may happen after the supernova ?

Answer 14

It may collapse more and form a neutron star or a black hole

Question 15

Why can light not escape fro ma black hole ?

Answer 15

Because they are incredibly dense and have a very strong gravitational field

Question 16

When did the big bang occur ?

Answer 16

14 billion years ago

Question 17

Explain the big bang theory

Answer 17

• a big bang happened
• the universe quickly expanded then cooled
• cooling allowed protons and electrons and neutrons to from
• cooling continued and neutrons combined to form simple nuclei
• the temp dropped enough for hydrogen to form

Question 18

Explain red shift as an argument for the big bang

Answer 18

• When we look at the light from distant galaxies it’s at the red end of the spectrum
• This tells us that the source is moving away from us
• therefore the universe is expanding

Question 19

What does CMBR stand for

Answer 19

cosmic microwave background radiation

Question 20

What is CMBR ?

Answer 20

It represents the after glow from the big bang. It has its own unique wavelength and can only be explained by the big bang.

Question 21

What are exoplanets ?

Answer 21

Planets outside our solar system

Question 22

How do we determine what a planets atmosphere is like ?

Answer 22

We use a solar absorption spectrum and see what the atmosphere consists of. ( planets with high oxygen in the atmospheres gives it a better chance that there may be life there)

Question 23

What are the 4 difficulties of space travel ?

Answer 23

• flight time ( our spacecraft are too slow)
• engineering ( spacecraft too slow)
• logistics (spacecraft cant carry enough fuel or food)
• ethics ( chance of failure would be high, no rescue)

Question 24

What are the distance to stars and galaxies measured in ?

Answer 24

light years

Question 25

What is a light year ?

Answer 25

the distance that light travels in one year

Question 26

equation for distance

Answer 26

distance = speed x time