The universe contains around 100 billion galaxies
Each galaxy can contain
hundreds of billions of
stars like our sun
Planets can orbit stars and that is what makes our solar system
The Hubble Telescope caught this image by looking at a single pixel of sky

Our Solar System contains:
• A Star: The Sun
• Planets: Which go around the Sun
• Satellites: Which go around planets
• Smaller objects: Such as asteroids and comets
The Solar System is often shown as being flat like this but it is really 3D

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus,
Neptune
You can remember this using the sentence:
My Very Excellent Mother Just Sent Us Nachos

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus,
Neptune
My Very Excellent Mother Just Sent Us Nachos
Create your own mnemonic to remember the order of the planets
M V E M J S U N

Add a diagram of the order of the planets to your mnemonic

Until 2006 we used to say
Pluto was a planet and that we had nine planets in the solar system
This was done because we were discovering too many objects the size of Pluto
We now call these Dwarf
Planets
Our Moon is bigger than
Pluto but can’t be a planet because it orbits Earth not the sun

Our solar system has two main asteroid fields
Asteroids are huge lumps of rock that aren’t big enough to be planets. They often contain metal ore https://www.youtube.com/watch?v=DrbCAoiyUNw

Comets are collections of
ice, dust and small rocky particles
They tend to have very long highly elliptical orbits
Halley’s comet is one of the most famous and is visible in the sky every 76 years

We used to believe that the Earth was at the
centre of the universe and everything orbited us
Space exploration and use of telescopes means that we now understand that the Earth orbits the Sun
Heliocentric is named after the Greek god Helios which means Sun

The Earth is constantly
rotating on a tilted axis
This causes night and day
The Earth also orbits the
Sun
This causes seasons
From space you can see a definite line between
night and day as the
Earth rotates

The Earth is on a tilted axis
Every 24 hours the
Earth turns around this axis once

NIGHT DAY
It is always day on the side of the Earth that faces the
Sun

The Sun appears to move across the sky but this is really the
Earth rotating
The position of the
sun also affects our shadows
E W

If it was 4:00 in London what time would it be in…
Place
Casablanca
Pretoria
GMT Time
+1
+2
05:00
Antanarivo
Philippines
+3
+8
06:00
07:00
12:00
We belong to the GMT time zone which stands for Greenwich Meridian
Time

Daylight savings time is when we move the clock forwards by one hour in
spring take it back off in autumn.
This is so that it is lighter during the evenings so lights don’t have to be used and people can shop.
Not every country uses
daylight savings time. It is mostly used in America and
Europe.

Task: Read the article and write a response back to
Chris Hill explaining why he is wrong.
Include:
• An explanation as to how he is mistaken.
• What daylight savings time is.
• Why it is used.

Seasons are caused by the
Earths tilted axis and its position in orbit around the Sun
The seasons in the
northern hemisphere are always the opposite of those in the southern hemisphere
Everything above the
equator is in the northern
hemisphere everything below in the southern hemisphere

Seasons happen due to
Earth being on a tilted axis
When the northern
hemisphere is pointed towards the Sun it is
Summer in the UK
When the southern
hemisphere is pointed towards the Sun it is Winter
Globes also rotate on a tilted axis to represent how the real planet does

The tilted axis of the Earth makes the Sun appear
lower in the sky during Winter

The Moon is Earths natural satellite
A satellite is something that orbits a larger body
It is a natural satellite because it is not man made
Scientists believe the moon was once part of Earth but was blasted off in a collision as the Earth formed

The Moon is held in orbit around the Earth by
Earth’s Gravity
It does not produce its own light like stars do, it just reflects the suns rays
This is why we can see it at night
The moon can sometimes appear to be orange. This is caused by our atmosphere
scattering the light it reflects

It takes the Moon 28 days to orbit the Earth
Over these 28 days the
Moon appears to change shape
This is because only half of the Moon is facing the Sun and we can’t see the dark side
This shows how the moon appeared over the course of a month

A solar eclipse happens when the Moon passes between the Sun and the
Earth. This casts a shadow over the Earth
A lunar eclipse happens when the Earth passes between the Sun and the
Moon. This casts a shadow over the Moon.
Solar eclipses are very rare however lunar eclipses happen most years

Solar Eclipse
Lunar Eclipse

The nearest star to us is the sun
We sometimes think of
stars as being very tiny, especially when we look up at the night sky
This is only because they are very far away z

A galaxy is a collection of hundreds of billions of
stars orbiting around a supermassive black hole at the centre
Our galaxy is called the
Milky Way and contains around 300 billion stars just like the Sun
Our Galaxy will one day collide with its closest neighbour Andromeda

Gravity is an attractive
force that affects anything with mass
Even people attract other objects with gravity but our mass isn’t large enough for the force to be very strong
Isaac Newton
discovered gravity when an apple fell on his head

Mass is the amount of
matter (or stuff) an object contains
Mass is measured in
grams (g)
An objects mass is the same wherever it is
An Elephant contains more matter than a mouse so has more mass

Gravity pulls down to the centre of the earth no matter where you stand on it
GRAVITY

The effects of gravity only become significant when objects get to the mass of a moon or planet
The more mass an object has the stronger its gravity will be
The sun has the most mass out of anything in our solar system so it has the most gravity

Gravity and Mass are directly proportional
This means as you increase one the other increases at the same rate
If you double the mass of an object you double its gravity https://www.youtube.com/watch?time_continue=4& v=uhS8K4gFu4s

Gravity gets weaker the further away you get from an object
Every time you double the
distance from an object the effect weakens by four times You don’t have to be far from earth to appear weightless

Gravity is changed by two things:
Mass: When we double the mass we
double the effects of gravity
Distance: When we double the distance

Orbiting is when an object
travels around another due to gravity
Objects will only orbit things with a higher gravitational
force than themselves
E.g. The Moon orbits the
Earth and the Earth orbits the Sun
Orbits are usually circular but not always
They can also be elliptical

The further away a planet is from the sun the longer it takes for it to orbit it
The time for a planet to
orbit a star is called a year
A year on Earth is longer than a year on Mercury
The length of a year on
Earth is 365 days
On Neptune a year is 60048 days long

The further away from the Sun a planet is the slower it travels

Weight is a force caused by gravity
Weight is the gravitational
force between objects
Because weight is a force it is measured in Newtons
(N)
People usually use the word weight wrong and get it confused with mass

Wherever you are in the
universe your mass will be the same
But depending on how
strong the gravity is you can weigh different amounts
Because gravity is weaker on the moon astronauts weigh very little

On earth you wouldn’t be able to lift a safe because it would weigh too much

On the moon the safe would have the same mass but its weight would be lower

Because it weighs less you would be able to pick up the safe

Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)
Earths gravitational field
strength is 10N/Kg
If a man had a mass of 80kg then you could enter those numbers into the formula to calculate his weight
Weight = 10 x 80 = 800N
M
W x G
W: Weight
M: Mass
G: Gravitational Field
Strength

Artificial Satellites are man-made objects that are launched in to space and orbit Earth
They are held in orbit by
Earth’s gravity and their own velocity
Over time their orbit will
decay and they can fall back to Earth
This shows all the satellites and space debris in low
Earth orbit

Satellites have many uses including:
• Communications
• Global Positioning System
• Predicting Weather
• Scientific surveys of the
Earth's surface
• Map making
• Spying
• TV
Satellites use solar panels as a renewable way to power their systems

A telescope in space has no light pollution or interference from the atmosphere
They are incredibly
expensive though
The Hubble Space
Telescope was launched in
1994
When the Hubble was first launched it didn’t work
It needed ‘spectacles’ due to a mistake

Space probes are used to explore our solar system and beyond
Because they are unmanned they can be made quite small and they don’t need to carry
food or oxygen
This makes them a lot
cheaper than manned space flights
Voyager 1 was launched in
1977 and is very close to entering interstellar space
Every year it travels the same distance as there is between the Earth and Sun

The space race between
America and Russia culminated in Neil
Armstrong setting foot on the Moon in 1969
Humans have yet to travel further due to the time, money and resources it would take
Laika the dog was the first living thing to orbit the Earth and also to die in orbit