Space Physics Flashcards
What is the first stage of a star?
A cloud of dust and gas called a nebula. The force of gravity pulls the dust and gas together to form a protostar.
What is the second stage of a star?
A star is born- As the star gets denser, the temperature rises and more particles collide. When the temperature gets high enough, hydrogen nuclei undergo nuclear fusion to form helium nuclei. This gives out huge amounts of energy, which keeps the core of the star hot.
What is the third stage of a star?
It enters a long stable period where the outward pressure caused by the nuclear fusion that tries to expand the star balances the force of gravity pulling everything inwards. This is called a main sequence star and it typically lasts several billion years.
What happens in the fourth stage of a star?
Eventually, the hydrogen begins to run out. The star then swells into either a red giant (if small) or a red supergiant (if large). It becomes red because the surface cools. Fusion of helium and other elements occurs. Heavier elements up to iron are created in the core of the star.
What happens in the stage after a red giant?
A small star then becomes unstable and ejects its outer layer of dust and gas. This leaves behind a hot, dense, solid core called a white dwarf.
What happens in the stage after a white dwarf?
As a white dwarf cools down it emits less and less energy. When it no longer emits energy a significant amount, it is called a black dwarf.
What happens in the stage after a red supergiant?
A Supernova. Big stars start to grow brightly again as they undergo more fusion and expand and contract several times forming elements as heavy as iron in various nuclear reactions. Eventually they will explode in a supernova, forming elements heavier than iron and ejecting them into the universe to form new planets and stars.
What happens after an exploding supernova?
It throws the outer layers of dust and gas into space leaving a very dense core called a neutron star. If the star is massive enough it will become a black hole - a super dense point in space not even light can escape from.
List the names of stars throughout their life cycle, in order.
Nebula
Protostar
Main Sequence star
Red Giant/ White dwarf/ Black dwarf
Red Super Giant/ Supernova/ Neutron star or black hole
How many stars does our solar system have?
1 - The sun.
What stage is the sun in currently and what type of star is it?
Stage 3 - It is a main sequence star.
How many planets orbit the sun?
8
List the 8 planets, starting with the one closest to the sun.
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Name a dwarf planet in our solar system.
Pluto
What are planets?
Large objects that orbit a star. There are eight in our solar system. They have to be large enough you have ‘cleared their neighbourhoods’, meaning their gravity is strong enough to have pulled in any nearby objects apart from their satellites.
