Physics WJEC GCSE Stars and Planets Unit 2.5

Double And Triple

What does the solar system consist of?

The Sun, Planets, Moons, Dwarf Planets, Comets

Where is the Asteroid belt? What is there?

Between Mars and Jupiter, there is thousands of rocky asteroids and dwarf planets

What is a dwarf planet?

A body similar to a planet but too small to be classed one

3 examples of dwarf planets?

1. Pluto

2. Eris

3. Ceres

What do comets consist of? Where are they “made”?

Ice and dust, beyond the orbit of Neptune

What is Astronomical Units?

The mean distance from earth to the sun

What is one Astronomical Unit (Au)?

150,000,000 Km

What is a Light Year?

The distance light travels in one year

What is the first stage of SOLAR SYSTEM formation?

Clouds of Gases, mainly Hydrogen Helium and dust from Super Novas, get pulled together by Gravitational Forces, causing the cloud to collapse and particles to collect together

What is the second stage of SOLAR SYSTEM formation?

As the cloud collapsed, it begins to spin, into a disk

What is the third stage of SOLAR SYSTEM formation?

The centre of the Disk becomes the Sun, excess collects together to form planets, moons, asteroids etc.

Why are inner planets rocky?

Because it was too close to the sun for any of the light gaseous particles to condense, so they were pushed further away from the Sun

Why are Outer Planets Gaseous?

Because it is further from the sun, so the elements were able to condense and form gas giants.

What key process do stars depend on?

The Fusion of elements, to release energy

What 2 forces does the stability of stars depend on?

1. Gravity acting inwards

2. Radiation and gas pressure acting outwards

What are stars made up of?

Hydrogen, Helium and Dust

When do protostars form?

When gravity collects clouds of gas (H, He and dust) together. As they compress they heat up

What fuses in Main Sequences Stars? To make what? What does this fusion cause?

Hydrogen, to form Helium. Creates enough radiation and gas pressure to balance the gravitational force

What starts large mass stars? What does this increase?

Helium fusing into larger elements like iron, this increases the gas and radiation pressure

What will a large mass star expand into?

Into a super giant

What happens after helium gas begins to run out in large mass stars?

Star becomes very unstable and explodes into a Super Nova, throwing gas and dust out into space, high temperature and pressure causes fusion of the heavier elements

What happens after a super nova explosion?

Remaining matter collapses due to gravitational force, as gas + radiation pressure is small, and will shrink to form a Neutron Star or a Black Hole

What starts a Low Mass Star?

Helium fusing into larger elements like Carbon, increasing gas and radiation pressure, star will expand into red giant.

How will a low mass star sequence end?

Helium fuel begins to run out, reaction will slow. Gas and radiation pressure will decrease, star will shrink into white dwarf