Cosmology Terminology

Big Bang

The origin of the universe.

Black Hole

An object that has gravity so strong that light can not even escape it. Black holes form when massive stars collapse at the end of their lives

Galaxy

A group of millions or billions of stars held together by gravity.

Large Star

A star with more than 8 times the mass of the sun.

Light - Year

the distance light travels in a year

Main Sequence Star

A main sequence star is a star in the most stable and longest phase of its life. It is currently fusing hydrogen into helium in its core.

Neubla

a vast cloud of dust and gas in space

Neutron Star

The remains of the core of a large star. It has many neutrons densley packed in.

Nucelar Fusion

a nuclear reaction in which two atomic nuclei join together

Nuclear Reaction

A reaction in which an atom’s nucleus changes.

Planetary Nebula

a nebula formed from a red giant star

Prostar

a dense ball of gas that has not formed into a star yet.

Red Giant

a small star that fuses helium causing its outer layer to expand

Red Supergiant

a large star that fuses helium causing its outer layer to expand

redshift

the stretching of light waves emitted by objects moving away from us.

Star

hot ball of gas held together by gravity

supernova

an explosion of a red supergiant star

white dawrf

the remains of the core of a white star

Doppler Effect

The change in the way you hear a noise as it moves toward or away from you

How does the Doppler Effect cause red and blue shift

If a star is moving away from us, its light appears redshifted (shifted towards the red end of the spectrum, with longer wavelengths), and if it's moving towards us, its light appears blueshifted (shifted towards the blue end, with shorter wavelengths)

Life cycle of a normal star

1. Nebula

2. ProStar

3. Main Sequence Star

4. Red Giant

5. Planetary Nebula

6. White Dwarf

Life cycle for massive stars

1. Nebula

2. ProStar

3. Main Sequence Star

4. Red Supergiant

5. Supernova

6. Neutron Star or Black Hole

Using Light Colour and Brightness to Identify Star Properties

Blue/White Stars: Hottest stars

Yellow Stars: Intermediate stars like the sun

Orange/Red Stars: Cooler stars

What do Hertzsprung-Russel diagrams show

It plots stars based on their brightness and temperature