Gcse Physics Paper 2 - Topic 8 - Space Physics

Front 1

What is at the Centre of our Solar System?

Back 1

At the Centre of Our Solar System is the Sun.

The Sun is a Star.

Front 2

Describe the 8 Main Planets Orbiting the Sun

Back 2

Mercury, Venus, Earth and Mars are Relatively Small, Rocky Planets.

Jupiter, Saturn, Uranus and Neptune are Much Larger.

Beyond Neptune are Dwarf Planets. Pluto is a Dwarf Planet and is Extremely Small.

Front 3

What Does Our Solar System Contain?

Back 3

The Solar system is just a Tiny Part of the Milky Way Galaxy which Contains Hundreds of Billions of Stars.

1) Our Solar System has 1 Star - The Sun.

2) Planets = Large Objects that Orbit a Star. There are 8 in our Solar System.

3) Dwarf Planets

4) Moons = Natural Satellites which Orbit Planets. Most of the Planets in the Solar System have at Least 1 Moon.

5) Artifical Satellites = Man-Made Satellites that Orbit the Earth.

Front 4

Describe The Life Cycle of Stars for Stars That are About the Same Size as the Sun

Back 4

1) Stars Initially Form from a Cloud of Dust and Gas Called a Nebula. The Force of Gravity Pulls the Dust and Gas Together to Form a Protostar.

2) As the Star gets Denser, the Temperature Rises and More Particles Collide with each Other.

When the Temperature Gets High Enough, Hydrogen Nuclei Undergo Nuclear Fusion to Form Helium Nuclei. This gives out a Huge Amount of Energy, which keeps the Core of the Star Hot.

3) At this Point, the Star Enters a Stable Period and Becomes a Main Sequence Star Where The Force of Gravity Acting Inwards is Balanced by the Force Due to Nuclear Fusion Acting Outwards.

Stars can Stay in the Main Sequence for a Very Long time.

4) Eventually the Hydrogen begins to Run Out and the Outward Force Due to Nuclear Fusion Becomes Less than The Inward Force of Gravity. This Causes the Star to Collapse Inwards which causes the Temperature to increase. Now Helium Nuclei Fuse Together to Create Heavier Elements (up to Iron) and the Star Expands into a Red Giant.

5) When the Red Giant Stops Fusing Helium, the Star Shrinks and Forms a White Dwarf.

6) Because the White Dwarf is no Longer Carrying out Fusion, it Cools Down and Eventually Stops Releasing Energy Forming a Black Dwarf.

Front 5

What is a Nebula?

Back 5

Stars Initially Form from a Cloud of Dust and Gas Called a Nebula.

Front 6

What is a Protostar?

Back 6

Stars Initially Form from a Cloud of Dust and Gas Called a Nebula.

The Force of Gravity Pulls the Dust and Gas Together to Form a Protostar.

Front 7

Describe How a Main Sequence Star is Stable

Back 7

When the Star's Outward Force Due to Nuclear Fusion Balances the Inward Force of Gravity, the Star Enters a Long Stable Period and Becomes a Main Sequence Star.

A Main Sequence Star is Stable Because these 2 Opposing Forces are Balanced - Scientists Say that the Star Is in Equilibrium.

Front 8

Draw a Diagram to Represent the Life Cycle of a Star that is About the Same Size of the Sun

Back 8

Left Side

Front 9

Describe the Life Cycle of a Star that is Much Bigger than the Sun

Back 9

1) Stars Initially Form from a Cloud of Dust and Gas Called a Nebula. The Force of Gravity Pulls the Dust and Gas Together to Form a Protostar.

2) As the Star gets Denser, the Temperature Rises and More Particles Collide with each Other.

When the Temperature Gets High Enough, Hydrogen Nuclei Undergo Nuclear Fusion to Form Helium Nuclei. This gives out a Huge Amount of Energy, which keeps the Core of the Star Hot.

3) At this Point, the Star Enters a Stable Period and Becomes a Main Sequence Star Where The Force of Gravity Acting Inwards is Balanced by the Force Due to Nuclear Fusion Acting Outwards.

Stars can Stay in the Main Sequence for a Very Long time.

4) Eventually the Hydrogen begins to Run Out. The Star then Expands into a Red Super Giant and Helium Nuclei Fuse Together to Produce Heavier Elements.

5) At Some point, the Red Super Giant Stops Carrying out Nuclear Fusion. Eventually, the Star Explodes in a Supernova, Forming Elements Heavier than Iron which are Distributed and Ejected throughout the Universe.

6) After the Supernova, the Remains of the Star can Either Form a Neutron Star (which Consists of Neutrons densely packed Together) or a Black Hole - Which has such a Large Gravity that Not Even Light can Escape.

Front 10

What is the Difference Between Red Giants and Red Super Giants?

Back 10

Red Giants are Formed from Stars about the Same Size as the Sun.

Red Super Giants are Formed from Stars Much Bigger than the Sun.

Front 11

How are Elements Heavier than Iron Produced During the Life Cycle of a Star?

Back 11

Elements Heavier than Iron are Only Produced in a Supernova.

A Supernova is the Explosion after the Red Super Giant. When the Supernova Explodes, These Elements are Distributed throughout the Universe.

Front 12

After the Supernova, the Remains of the Star can Form 1 of 2 Objects.

What are these Objects?

Back 12

After the Supernova, the Remains of the Star can Form 1 of 2 Objects:

1) Neutron Star

2) Black Hole

Front 13

Describe a Neutron Star

Back 13

A Neutron Star Consists of Neutrons Densely Packed Together.

Front 14

Describe a Black Hole

Back 14

A Black Hole has such a Large Gravity that Not Even Light can Escape.

Front 15

What is a Circular Orbit?

Back 15

If an Object is Travelling in a Circle, we call this a Circular Orbit.

The Force of Gravity Holds Objects in their Orbits.

E.g. The Earth Orbiting the Sun,

The Moon Orbiting the Earth

Front 16

How Do Planets Orbit the Sun?

Back 16

Planets Orbit the Sun and the Force of Gravity Holds the Planets in their Orbits.

Front 17

Describe the Differences between Planets, their Moons and Artifical Satellites

Back 17

The Force of Gravity Holds Objects in their Orbits.

Planets Orbit the Sun. The Force of Gravity Holds the Planets in their Orbits.

The Moon is a Natural Satellite that Orbits the Earth. The Force of Gravity Holds the Moon in its Orbit.

Artifical Satellites are Man-Made. Geostationary Satellites Orbit once Every 24 Hours so they Always Point to the Same Part of the Earth. However Other Artifical Satellites Orbit More Frequently.

Front 18

Give an Example of an Artifical Satellite

Back 18

Artifical Satellites are Man-Made.

Geostationary Satellites Orbit once Every 24 Hours so they Always Point to the Same Part of the Earth.

However Other Artifical Satellites Orbit More Frequently.

Front 19

Explain How for Circular Orbits, the Force of Gravity can Change the Velocity of an Object but NOT It's Speed

Back 19

Velocity is the Speed of an Object in a Given Direction.

The Force of Gravity Holds Objects in their Orbits.

When an Object is Travelling in a Circle (e.g. Planet Orbiting the Sun), it is Constantly changing Direction. This means that the Velocity is Constantly Changing too.

However the Speed is Constant and Doesn't Change.

Therefore the Force of Gravity is Changing the Velocity but NOT the Speed.

Front 20

Explain How for a Stable Orbit, the Radius must Change if the Speed Changes

This is True for Both Satellites, Planets and Moons

Back 20

If the Speed of a Satellite/Moon/Planet Changes then the Radius of the Orbit must also Change.

If the Speed of the Object Increases then the Radius of its Orbit Decreases (distance decreases).

This is because at a Higher Speed, the Satellite needs a Greater Force of Gravity to Prevent it Flying off into Space.

By Moving Closer to the Earth, the Gravitational Force on the Satellite is Greater and the Satellite Remains in a Stable Orbit.

Front 21

The Closer you get to a Star/Planet, the Stronger the ???

Back 21

The Closer you Get to a Star/Planet, the Stronger the Gravitational Force on the Object.

Front 22

Describe What is Red-Shift

Back 22

When we Look at Light from Most Distant Galaxies, we find that the Wavelength has Increased and the Pattern of Light has Shifted Towards the Red End of the Spectrum. This is Called Red Shift.

The Red Shift Tells us that Galaxies are Moving Away from Each Other and that the Source of Light (e.g. Star) is Moving Away from Us.

Galaxies that are Further Away have a Bigger Red Shift.

The Bigger the Shift, the Faster the Velocity of the Galaxy Moving.

Front 23

Describe How The Change of Each Galaxy's Speed with Distance is Evidence of an Expanding Universe

Back 23

Galaxies that are Further Away Have a Bigger Red Shift so these Galaxies are Moving Faster than Galaxies that are Closer.

The Fact that Distant Galaxies are Moving Faster than Nearby Galaxies Provides Evidence that the Universe is Expanding and Supports the Big Bang Theory.

It Shows that All Galaxies are Moving Away from Every other Galaxy, not just Ours.

Front 24

Describe the Big Bang Theory

Back 24

Scientists Believe that the Universe Began from a Very Small Region that was Extremely Hot and Dense.

This Region then Expanded into the Universe that we See Today and that Expansion is Still going on.

The Observed Red-Shift Provides Evidence that Space itself (The Universe) is Expanding and Supports the Big Bang Theory.

Front 25

Describe How Scientists are Able to Use Observations to Arrive at Theories Such as the Big Bang Theory

Back 25

In 1998, Scientists Assumed that Gravity would Cause the Expansion of the Universe to Gradually Slow Down.

However, Observations of Supernovae Show that the Rate of Expansion is Actually Increasing and that Distant Galaxies are Moving Away from Us Faster and Faster (the Speed at Which they're Receding is Increasing).

Front 26

Describe How There is Still Much about the Universe that Is Not Understood

E.g. Dark matter and Dark Energy

Back 26

Currently, Scientists Think that the Universe is Mostly Made up of Dark Matter and Dark Energy that we Cannot Detect.

It is Possible that these could Explain Why the Expansion of the Universe is Speeding Up.

However, No one Really Knows what these Things are, so there are Lots of Different Theories About it. These Theories get Tested Over Time and are Either Accepted or Rejected.