Space - paper 2

Question 1

Describe our solar system

Answer 1

the Sun, plus the eight planets and the dwarf planets that orbit around the Sun. Natural satellites, the moons that orbit planets, are also part of the solar system.

Question 2

State the name of our galaxy

Answer 2

The milky way

Question 3

How was the sun formed

Answer 3

The Sun was formed from a cloud of dust and gas (nebula) pulled together by gravitational attraction. This cloud heats up until fusion can start.

Question 4

What reaction takes places in all stars

Answer 4

Nuclear fusion

Question 5

Why are stars stable?

Answer 5

Fusion reactions lead to an equilibrium between the gravitational collapse of a star and the expansion of a star due to fusion energy.

Question 6

Describe the life cycle of a small star, like the sun

Answer 6

1. Nebula or Protostar
2. Main sequence star
3. Red Giant
4. White dwarf
5. Back dwarf

Question 7

Describe the life cycle of a large star

Answer 7

1. Nebula or Protostar
2. Main sequence star
3. Red Super Giant
4. Supernova
5. Neutron star or Black hole

Question 8

How is a red giant formed?

Answer 8

Hydrogen runs out and the star initially collapses as gravity is now the stronger force. After a star collapses, the star heats up enough for helium to fuse and it expands (radiation pressure > gravity)

Question 9

What type of star is the sun?

Answer 9

A main sequence star

Question 10

How is a white dwarf formed?

Answer 10

The red giant starts to run out of its fuel (Helium) Gravity is greater than radiation pressure so the star collapses

Question 11

Which was the first element created by the big bang

Answer 11

Hydrogen nuclei (protons)

Question 12

How were the light elements made

Answer 12

Fusion in stars

Question 13

How were the heavy elements made

Answer 13

Fusion in supernovas

Question 14

How were all the elements distributed through the universe

Answer 14

By supernovas

Question 15

What forces keeps planets in orbit around a star

Answer 15

Gravity

Question 16

What is a stable orbit?

Answer 16

A stable orbit is one in which the satellite’s speed is just right - it will not fly off into space (too fast) or spiral into the Earth (too slow) but will travel around a fixed path.

Question 17

What is the relationship between orbit radius and speed.

Answer 17

The gravitational attraction between two objects decreases with distance. This means that the closer the two objects are to each other, the stronger the force of gravity between them. This means that objects in small orbits travel faster than objects in large orbits. In order to change orbital speed, an object must change the radius of its orbit at the same time, to maintain a stable orbit.

Question 18

Define the doppler effect

Answer 18

The change in frequency of a wave, caused by relative motion between the source of the wave and the observer

Question 19

Why is the pitch higher when a car is moving towards you?

Answer 19

Wavelength is decreased so frequency is increased

Question 20

Why is the pitch higher when a car is moving away from you?

Answer 20

Wavelength increases so frequency has decreased

Question 21

Define red shift

Answer 21

There is an observed increase in the wavelength and decrease in frequency of light from distant galaxies.

Question 22

What is the relationship between the distance a galaxy is from Earth and thier speed?

Answer 22

The further away the galaxies, the faster they are moving and the bigger the observed increase in wavelength.

Question 23

Define Blue shift

Answer 23

A decrease in wavelength and an increase in freqency as a glaxaxy moves towards an observer.

Question 24

What evidence does red shift provide?

Answer 24

The observed red-shift provides evidence that space itself (the universe) is expanding which supports the Big Bang theory.

Question 25

What is the big bang theory

Answer 25

The Big Bang theory suggests that the universe began from a very small region that was extremely hot and dense.

Question 26

Describe the universe before the big bang

Answer 26

Hot and dense

Question 27

How can an object in orbit be travelling at a constant speed but still be accelerating

Answer 27

The object is constantly changing direction, so the velocity must be changing A change in velocity is an acceleration .

The object is always accelerating towards the centre of the orbit

Question 28

How many stars are in our solar system?

Answer 28

One - the sun

Question 29

What are natural satellites?

Answer 29

The moons that orbit planets

Question 30

What are the properties of dark matter?

Answer 30

1. It has mass
2. It cant be directly observed as it does not emit or absort em radiation
3. It is only effected by gravity
4. There is lots of it

Question 31

How do we know dark matter exists?

Answer 31

It can bend (refract) light

Question 32

Why do we think there is dark energy?

Answer 32

THe rate of expansion of the universe is accelerting