P16 - Space

Question 1

Order of the planets

Answer 1

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

Question 2

Groups of planets

Answer 2

• Small, rocky planets - Mercury, Venus, Earth, Mars
• Larger, gaseous planets - Jupiter, Saturn, Uranus, Neptune
• Dwarf planets - Pluto etc.

Question 3

What are moons

Answer 3

Natural satellites that orbit planets

Question 4

What galaxy are we a part of and what is a galaxy

Answer 4

• We are part of the Milky Way Galaxy
• A galaxy is a massive group of stars

Question 5

How do stars form

Answer 5

• First, it starts off as a cloud of dust and gas called a nebula. The gas is mainly hydrogen
• Gravity causes the cloud of dust and gas to collapse and as the gas particles move faster, the temperature rises to millions of degrees and this is known as a protostar
• If the temperature is high enough, hydrogen nuclei join together to form helium in nuclear fusion and this forms a main sequence star
• The star is in equilibrium as the gravitational force acts inwards and the forces as a result of fusion reactions acts outwards and these forces are balanced

Question 6

Lifecycle of a star about the same size as the Sun after the main sequence star phase

Answer 6

• The hydrogen starts to run out and the star collapses inwards as the inward force from gravity is greater than ther outward force
• This creates even higher temperature and pressure where helium nuclei fuse to form heavier elements
• The star expands to form a red giant
• When it stops fusing helium, the star collapses into a white dwarf
• It then cools to become a black dwarf

Question 7

Lifecycle of a star much bigger than the Sun after the main sequence star phase

Answer 7

• The hydrogen starts to run out and the star collapses inwards as the inward force from gravity is greater than ther outward force
• This creates even higher temperature and pressure where helium nuclei fuse to form heavier elements
• The star expands to form a red super giant
• When it runs out of helium nuclei, the star explodes in a supernova
• The temperature of a supernova produces elements heavier than iron and distributes these elements around the universe
• The star can then either form a neutron star or a black hole

Question 8

What is a geostationary satellite

Answer 8

• A satellite that orbits once every 24 hours
• They always point to the same part of the earth

Question 9

Comment on the speed and velocity of an object in a circular orbit

Answer 9

• The velocity is changing because the direction is constantly changing due to the force of gravity
• The speed doesn’t change

Question 10

What happens when you change the speed of an orbit

Answer 10

• if the speed increases, the radius of itts orbit decreases
• because at a higher speed, the satellite needs a greater force of gravity to keep it in a stable orbit

Question 11

What is the red shift effect

Answer 11

Light from distant objects in space becomes shifted towards the red end of the spectrum
This is beause the object is moving away from us which leads to the light waves emitted having an increased wavelength

Question 12

How does the distance of the galaxy determine the red shift

Answer 12

• The further away a galaxy is, the larger the redshift is as they are moving away much faster than the closer galaxies

Question 13

What is the Big Bang Theory and how does red shift support this

Answer 13

• The Big Bang Theory states that the universe began as a extremely small, dense and hot region whcih then exploded, expanding the universe and is the source of everything in the universe
• due to red shift, the fact that we know distant galaxies are moving away faster than nearby galaxies proves that the universe is expanding

Question 14

Examples of things in the universe that are still not understood

Answer 14

• Dark energy
• Dark matter
• These are used to try and justify the speed of expansion of the universe increasing but these are still not sure how it works