P16 Space Physics

Question 1

What are properites of our Sun?

Answer 1

• Main sequence star
• The only luminous object in out solar system; all other objects are non-lumious and they relfect light from the sun

Question 2

What are the eight planets of the Solar System?

Answer 2

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

Question 3

What are considered small planets?

Answer 3

• Mercury
• Venus
• Earth
• Mars

Question 4

What is a theory?

Answer 4

An explanation based on observable evidence and data

Question 5

Which planets are considered gas giants?

Answer 5

Jupiter,Saturn, Uranus and Neptune

Question 6

What are two criteria to classify an object as a planet?

Answer 6

1. The object must orbit the sun
2. It’s mass must be large enough to extract enough gravitational force to pull smaller objects

Question 7

Give two key features of a planet.

Answer 7

• They orbit in an elliptical path
• They have a cetripetal force acting on them

Question 8

How do you calculate the speed of planet?

Answer 8

2π x orbital radius / Time

Question 9

Why do planets around the sun have a circular motion?

Answer 9

Gravitational force between the Sun and plantes acts as the centripedal force to keep the planets in a circular motion

Question 10

What two factors can affect the Graviational force between the sun and the planets?

Answer 10

• mass of objects
• distance between two objects

Question 11

What is a satellite?

Answer 11

Something that orbits a planet

Question 12

What are the two types of satellites?

Answer 12

1. Natual - Moon
2. Manmade - Communication

Question 13

Which planets have moons?

Answer 13

• Small planets have none or very few moons
• Large gaseous planets have many moons due to their high mass resulting in a high graviational pull

Question 14

What are asteroids?

Answer 14

Large pieces of rock that orbit the sun

Question 15

Where is the asteroid belt?

Answer 15

Inbetween Mars and Jupiter

Question 16

What are comets?

Answer 16

Objects made of dust and ice
- they have in more elliptical paths then planets

Question 17

What is the Big Bang theory?

Answer 17

All matter and energy was concentrated at a single dense point which exploded sending matter and energy outwards thus creating the universe. The universe has been expanding ever since.

Question 18

What is the steady state theory?

Answer 18

There is no origin to the universe and it was already existing. The universe is expanding as galaxies moves away from each other

Question 19

What is evidence for the Big Bang theory?

Answer 19

• Red Shift
• Cosmic Microwave Background Radiation (CMBR)

Question 20

What is red-shift?

Answer 20

This is when an object producing visible light is moving away from the observer, it’s wavelength increases and the frequency decreases so that it is shifted towards the red end of the spectrum.

Question 21

What is Cosmic Microwave Background Radiation (CMBR)?

Answer 21

The Big Bang released a large amount of energy as waves with high energy, As the universe is expanding wave lentth of these energy waves increased and the frequency decreases. These waves currently exist as low energy microwaves in the background

Question 22

How does CMBR provide evidence for the Big Bang theory?

Answer 22

As the origin of CMBR can only be explained by the Big Bang

Question 23

What happens at the birth of a protostar?

Answer 23

1. Particles in nebula are attracted by gravitational force and they start to collide with each other
2. This releases a large amount of thermal energy
3. When the amount of energy is high enough it can start nuclear fusion reactions in a protostar

Question 24

What is nebula?

Answer 24

Large clouds of gases and dust

Question 25

What is the Life-Cycle of a a sun-sized star?

Answer 25

Nebula - Protostar - Main sequence star - Red giant - White dwarf - Black dwarf

Question 26

What is the life-cycle of a massive star?

Answer 26

Nebula - Protostar - Main sequence star - Red Super giant - Supernova - (Either a neutron star if small or Black hole if big)

Question 27

Why is the main sequence star stage the most stable stage of any star?

Answer 27

Because the outwards force created by nuclear fusion is balanced by inverse gravitational force

Question 28

What happens at red giant stage?

Answer 28

1.Rate of nuclear fusion slows down as the hydrogen fuel runs out meaning the inward gravitational force becomes stronger that outwards nuclear force.
2. The inner core of the star shrinks whereas the outer layer expands.
3. The star looks bigger and it’s temperature decreases.

Question 29

What happens at white dwarf stage?

Answer 29

1) The outer layer of red giant is ejected into space so that the star becomes smaller when it turns into a white dwarf.
2) Another set of nuclear fusion reactions starts to release more energy so that the star is hotter.

Question 30

What happens during then black dwarf stage of a star?

Answer 30

Nuclear fusion reactions stop and there is no emmission of any radiation

Question 31

What happens during the supernova stage of a star?

Answer 31

1) The outer layer of a red super giant is ejectd outwards and the inner layer condenses to form a supernova.
2)More nuclear fussion takes place to form elements heavier than iron.
3) When the amount of energy in a supernova is really high it undergoes through supernova explosion to form a neutron star (if the reminant is small) or black hole (if the reminant is large).