P8 - space physics

Question 1

Which galaxy is our solar system part of?

Answer 1

The Milky Way galaxy.

Question 2

How many planets make up our solar system?

Answer 2

Eight (plus the dwarf planets).

Question 3

What do the planets in our solar system orbit around and what type of body is it?

Answer 3

● The planets orbit around the sun

● The sun is a star

Question 4

What type of force pulled together the cloud of dust and gas to form the Sun?

Answer 4

Gravitational force of attraction.

Question 5

What word is used to describe a cloud of dust and

gas?

Answer 5

A nebula.

Question 6

What type of reactions take place at the start of a star’s life cycle as dust and gas is drawn together?

Answer 6

Fusion reactions.

Question 7

What factor determines the type of lifecycle a star undergoes?

Answer 7

The size of the star.

Question 8

Which two phases do all stars of the same or greater size than the sun undergo?

Answer 8

1. Protostar phase

2. Main sequence phase

Question 9

What do stars of a similar magnitude to the sun

become at the end of their life-cycle?

Answer 9

A black dwarf.

Question 10

What two things can stars much bigger
than the sun become at the end of their
lifecycle?

Answer 10

1. Neutron star

2. Black hole

Question 11

What two phases do stars of similar size to the sun go through between being a main sequence star and a black dwarf?

Answer 11

1. Red giant

2. White dwarf

Question 12

What two phases do stars of greater size than the
sun go through between being a main sequence star
and a neutron star/black hole?

Answer 12

1. Red super giant

2. Supernova

Question 13

What are produced during the fusion processes in a

star?

Answer 13

All of the naturally occurring elements.

Question 14

What condition is required for fusion reactions to

occur in a star?

Answer 14

Very high temperatures.

Question 15

How are elements heavier than iron produced?

Answer 15

In a supernova.

Question 16

What type of nuclei fuse together to form heavier elements in a star?

Answer 16

Hydrogen nuclei fuse to form heavier

elements.

Question 17

How are elements distributed throughout the

universe?

Answer 17

Through the explosion of a massive star

supernova

Question 18

What allows planets and satellites to maintain

circular orbits?

Answer 18

● Gravity provides the gravitational force
that acts as the object’s centripetal force

● The presence of a centripetal force
allows for the object to maintain its
circular orbit

Question 19

What type of satellite can a planet’s moon be

described as?

Answer 19

A natural satellite

Question 20

Give two examples of artificial satellites.

Answer 20

1. TV satellites

2. Satellites used for satellite imaging

Question 21

Explain why for a stable orbit, the radius of orbit

must change if the speed changes.

Answer 21

● At higher speeds, the object requires a greater centripetal force

● For a greater centripetal force, the
gravitational force must increase

● This is achieved by the radius of the orbit
being reduced

Question 22

Explain how the force of gravity acting on

a satellite affects its speed and velocity

Answer 22

● The force can alter its velocity since the
direction is continually changing

● It can’t cause a change of speed since
there is no force component in the direction
of motion

Question 23

What is red-shift?

Answer 23

An observed increase in the wavelength

of light from distant galaxies.

Question 24

What two things can be said about the motion and wavelength of emitted light from a galaxy, the further away it is?

Answer 24

● The further away a galaxy is, the faster it is
moving

● The further away a galaxy is, the greater
the observed increase in wavelength

Question 25

What does red-shift provide evidence for?

Answer 25

● Provides evidence that the universe is
expanding

● Supports the Big Bang theory

Question 26

What does the Big Bang theory suggest?

Answer 26

The entire universe started from a very

small, hot and dense region in space

Question 27

Compare the observed red-shift of two galaxies, one further away than the other.

Answer 27

● The galaxy that is further away is
travelling faster

● The observed red-shift is greater the
further away it is

Question 28

What did scientists observe to provide evidence that the universe is expanding at an ever faster rate?

Answer 28

They observed supernovae, which
suggested that galaxies are moving
away at an ever faster rate.

Question 29

Prior to observations of supernovae, what was
believed about the rate of expansion of the universe
and why

Answer 29

● The rate of expansion was expected to
occur at an ever slower rate

● It was thought that gravitational forces
would cause this slowing down

Question 30

What two ideas could explain the
universe’s ever increasing rate of
expansion?

Answer 30

● The existence of energy and mass that we
can’t detect, known as dark matter and dark
energy

● These ideas are still being developed by
scientists and are not yet fully understood