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What is astronomy?
This is the study of the universe and everything in it
What are astronomers?
These are the scientists who study the universe and everything in it
What are the two views about the universe?
1. Ptolemy's geocentric model believes that the Earth is at the centre of the universe
2. Copernicus's heliocentric model believes that the Sun is at the centre of the universe
What is the universe?
This is made up of everything that exists including planets, stars, galaxies and all forms of matter and energy
What is the Big Bang Theory?
This is an idea that scientists use to explain how our universe was formed
What is a galaxy?
A galaxy is a large group of stars, dust, gas and dark matter held together by gravity
State the galaxy that Planet Earth is in
The Milky Way
What is antimatter?
This is the mirror image of matter
Explain Hubble's Law
This states that galaxies are moving away from each other
The further away a galaxy is the faster the galaxy is moving away from us
What is a celestial body?
This is any natural body outside of the Earth's atmosphere
Planets, stars, moons, comets and asteroids are examples of celestial bodies
List examples of celestial bodies
What is a planet?
A planet is an object that:
1. is in orbit around a star
2. has enough mass to have a nearly round shape
3. has enough gravity to clear the space waste in its orbit
What is a moon?
This is a natural body which orbits a planet
What is a star?
A star is a luminous object made up of gas that can produce its own light and heat by nuclear reactions
State an example of a star
What colour is the hottest star?
What colour is the coolest star?
Describe the life cycle of a star
1. In a nebula the dust and gas from space are pulled together by gravity. The friction causes heat and the nuclei of hydrogen to join together. A star is now formed
2. The star remains stable for millions of years. When the star runs out of hydrogen fuel, fussion slows down
3. The temperature decreases and the star expands to form a red giant
4. Eventually the inner core of the star collapses under gravity to form a very hot and dense white dwarf
5. The white dwarf fades out as fusion reactions stop. The star goes cold and becomes a black dwarf
What is a light year?
This is the distance that light travels in one year
What causes the twinkle in the stars?
Turbulence in the Earth's armosphere
What are asteroids?
These are lumps of rock that orbit the Sun
They are too small to be classified as planets
They have no air and no atmosphere
State where the asteroid belt is located?
It lies between Mars and Jupiter
Describe the three types of asteroids
1. C-type asteroids are made up of carbon compounds
2. S-type asteroids are made up of stony materials
3. M-type asteroids are mostly made of metals, such as iron
What are meteors?
Meteors are asteroids that are about 10 metres wide
These are rocks that burn up in the Earth's atmosphere, leaving shooting star trails behind them
What are planetoids?
These are asteroids that are about 100 kilometres wide
It is called a 'dwarf' planet because they are too large to be asteroids and too small to be called planets
What is a comet?
This is a small lump of ice and dirt that orbits the Sun
Where are comets found?
They are found in the Kuiper Belt or the Ooort Cloud
Where is the Kuiper Belt located?
It is found beyond Neptune
Where is the Oort Cloud located?
It is found at the edge of our solar system
Describe Halley's Comet?
This is the most well-known comet in the solar system
It orbits the Sun and can be seen with the naked eye from Earth approximately every 75 years
It is due to return again in 2061
How many planets is there in our solar system?
8 planets - 4 inner planets and 4 outer planets
What are the four inner planets called?
Terrestrial planets because they are made up of rock
List the four inner (terrestrial) planets?
What are the four outer planets called?
Gas giants because they are mainly made of gases hydrogen and helium
They are very large and have rings around them
List the four outer planets (gas giants)?
This is the non contact force of attraction between objects
Define force field
This is a region in space where an object feels a force
Define gravitational force field
This is a region in space where an object that has mass feels the force of gravity