Space physics

What is there at the centre of the solar system

The sun which is a star

How many planets orbit the sun

8

What are the four rocky planets

Mercury, Venus, earth and mars

What are the four gas giants

Jupiter, Saturn, Uranus and Neptune

What are dwarf planets

Smaller planets which are beyond Neptune’s orbit such a pluto

What are the celestial bodies in space (5)

Planets, stars, comets, asteroids and moons

What is a moon

A natural satellite which orbits a planet

What is a galaxy

A massive clump of stars

What galaxy is the solar system part of

Milky Way galaxy

What are stars formed by

Clouds of dust and gas called nebulas

How does a star formed

• gravity causes the nebula to collapse

• The temperature rises to millions of degrees as the particles move faster

• This is now a protostar

• The temperature rise causes hydrogen to fuse into helium via nuclear fusion

• A star is born

How is a star in equilibrium

The inward force of gravity in the star is equal to the outward force of nuclear fission

What is the lifecycle of a star like our sun

Main sequence star → collapsed star → red giant → planetary nebula → white dwarf → black dwarf

Explain the lifecycle of a smaller star

The star begins to collapse as the star runs out of hydrogen. Fusion then forms heavier elements which forms a red giant. This then forms a planetary nebula as the red giant sheds its outer layers due to fuel depleted ion. This then cool down to forms a white dwarf and eventually a black dwarf when no energy is released anymore

What is the lifecycle of a bigger star

Main sequence star → super red giant → supernova → neutron star if smaller

→ black hole if bigger

What is a supernova

When a star explodes

What is the heaviest element a super red giant can fuse

Iron

How did elements heavier than iron come about

The super high temperatures of a supernova fuses elements heavier than iron which is then distributed by the explosion

How is earth orbiting the sun

The force of gravity keeps the earth in a circular orbit

What apart from the moon orbits the earth

Made made satellites

What is a geostationary satellite

A satellite which orbits every 24 hours so it points to the same point of the earth

Why do circular orbits lead to a change of velocity but no change in speed

The direction constantly changes but the speed remains constant

Why does the radius of the orbit depend on the speed of the satellite

If the speed increases, the radius decreases as it now needs a higher force of gravity to keep it in orbit

What causes the red shift

Light from distant galaxies have an increased wavelength than light from closer galaxies

How can we visualise the red shift effect

The wavelengths of distant galaxies shift towards the red end of the spectrum

What does the red shift tell us

The galaxies are moving further away from each other

Why do galaxies in the distance move faster

They have a bigger red shift

What is red shift proof of

The universe is expanding

What is the Big Bang theory

The universe began as a small hot and dense region which expanded

What is happening to the rate of the universe expanding

It’s getting faster which scientists can’t explain

What is undetectable energy and matter called

Dark energy and dark matter

What is the possible explanation of the rate of expansion getting faster

Dark energy and dark matter