P16(Space)

Question 1

How did the sun form

Answer 1

Formed at the centre of a spinning cloud of dust,gas and rock due to the force of gravity

Question 2

What is a protostar

Answer 2

A concentration of gas and dust that becomes hot enough to cause nuclear fusion

Question 3

How does a star form

Answer 3

-When a protostar temperature increases and it gets hotter
-therefore the process of nuclear fusion can take place
-therefore energy is released in the fusion of hydrogen nuclei into helium nuclei
-causing the protostar to get hotter and brighter
-therefore causing a star to be born

Question 4

How is energy released inside a star

Answer 4

Hydrogen nuclei fuse together to form helium nuclei

Question 5

How is a star stable

Answer 5

-Energy released in the core makes the fusion process continue
-Therefore radiation such as gamma radiation flows out from the core in all directions
-The force of gravity acts inwards making the star contract
-The radiation from nuclear fusion in its core acts outwards making the star expand

Question 6

When do stars become unstable

Answer 6

When stars have no more hydrogen nuclei in their cores that can fuse together

Question 7

What is the lifecycle of a star with a similar mass to our sun

Answer 7

Protostar—> main sequence —> red giant —> white dwarf —> black dwarf

Question 8

What is the lifecycle of a star with a greater mass than our sun

Answer 8

Protostar —> main sequence star —> red supergiant —> supernova —> black hole or neutron star

Question 9

What is a red giant

Answer 9

Stars with a similar mass to our sun swell out and cool down and turn red

Question 10

What is a white dwarf

Answer 10

Hot dense white star much smaller in diameter than it was before

Question 11

What is a black dwarf

Answer 11

When white dwarfs fade out and go cold

Question 12

What is a red supergiant

Answer 12

Stars much bigger than the sun swell out and collapse

Question 13

What is a supernova

Answer 13

The explosion of a red supergiant after it collapses

Question 14

What is a neutron star

Answer 14

An extremely dense object made up of only neutrons

Question 15

How do neutron stars form

Answer 15

The supernova compresses the core of the star into a neutron star

Question 16

What is a black hole

Answer 16

An extremely dense object where the gravitational field strength is so strong that nothing can escape from it

Question 17

How do black holes form

Answer 17

The supernova compresses the core of the star into an extremely dense object

Question 18

How does a planet stay in its orbit

Answer 18

The force of gravity between a planet and its host star keeps the planet moving along its orbit

Question 19

How are circular orbits formed

Answer 19

-Objects in circular orbit are travelling at a constant speed
-The orbit is a circular path
-therefore the direction in which the object is travelling will be constantly changing direction
-A change in direction causes a change in velocity
-Acceleration is the rate of change of velocity
-therefore if the object is constantly changing direction then its velocity is constantly changing
-so the object in orbit is accelerating
-A resultant force is needed to cause an acceleration
-This resultant force is gravity and it must act at right angles to the instantaneous velocity of the object to create a circular orbit
-This is always towards the centre of the orbit

Question 20

Planet’s furthest from the sun …

Answer 20

Take the longest amount of time to orbit the sun because they travel at the slowest speeds

Question 21

Planet’s closest to the sun …

Answer 21

Take the shortest amount of time to orbit the sun because they travel at the fastest speeds

Question 22

A satellite needs to travel at a specific speed to …

Answer 22

maintain a circular orbit at a particular distance from the object

Question 23

If the speed of the satellite is too big …

Answer 23

-The radius of the orbit will increase and the satellite will spiral into space
-This is because the gravitational attraction cannot provide enough force to keep it in orbit

Question 24

If the speed of the satellite is too small …

Answer 24

-The radius of the orbit will decrease and the satellite will move towards the object it should -be orbiting
This is because the gravitational attraction is too strong to maintain a constant orbital radius

Question 25

If an artificial satellite is to change the radius at which it is orbiting then the …

Answer 25

speed at which it is travelling must change

Question 26

To maintain a stable orbit:
If the speed increases…

Answer 26

the radius must increase

Question 27

To maintain a stable orbit:
If the speed decreases…

Answer 27

the radius must decrease

Question 28

What is the Doppler effect

Answer 28

-The wavelength of the waves in front of the source decreases and the frequency increases
-The wavelength behind the source increases and the frequency decreases

Question 29

What is blueshift

Answer 29

If an object moves towards an observer the wavelength of light decreases

Question 30

What is red shift

Answer 30

If an object moves away from an observer the wavelength of light increases

Question 31

The further away a distant galaxy is …

Answer 31

The greater it’s red shift

Question 32

What did Edwin Hubble discover

Answer 32

-The light from distant galaxies was red shifted
-Therefore distant galaxies are moving away from earth
-Therefore the universe is expanding

Question 33

The greater the distance a galaxy is from Earth…

Answer 33

The greater the speed at which it is moving away from Earth

Question 34

What is the Big Bang theory

Answer 34

-Around 14 billion years ago, the universe began from a very small region that was extremely hot and dense
-Then there were a series of explosions, which we call the Big Bang
-This caused the universe to expand, cooling as it does so, to form the universe we currently observe

Question 35

What is CMBR(cosmic microwave background radiation)

Answer 35

Electromagnetic radiation that was created just after the Big Bang

Question 36

What is dark matter

Answer 36

-Evidence from the rotation and motion of galaxies suggests that there is much more matter in the Universe than we are able to account for
-This unseen matter is given the name dark matter and its nature is not currently known

Question 37

What is dark energy

Answer 37

-Measurements of the expansion of the Universe using supernovae suggest that the Universe is starting to expand at a faster rate
-It has been suggested that this accelerated motion is caused by dark energy pushing everything in the Universe apart

Question 38

If the density of the universe is less than a particular amount it will ….

Answer 38

-Expand forever
-causing the stars to die out
-therefore causing everything else to die

Question 39

If the density of the universe is more than a particular amount it will …

Answer 39

-Stop expanding and go into reverse
-All matter will then clump together into a single dense point

Question 40

What is the evidence for the Big Bang theory

Answer 40

The red shifts of distant galaxies