Big Bang

What is the Big Bang theory?

The big bang theory is the theory that all matter, energy, and space in the observable universe rapidly expanded from a single dense point 13.8 billion years ago.

CMBR

Detectable electromagnetic radiation that is present throughout the universe that is thought to be the cooled remnants of the big bang.

Dopler effect

Is the apparent change in the frequency of a wave caused by relative motion between the source of the wave and the observer.

Redshift

A shift in the lines of an object's spectrum toward the red end. Redshift indicates that an object is moving away from the observer. The larger the redshift, the faster the object is moving.

Emission spectrum

Light years

The distance light travels in one year

Stars differentiate because of

Mass
luminosity
colour
temperature

Colour

Apparent magnitude

How bight the star appears from earth

Absolute magnitude

How bright the star appears from the standard distance of 10 parsecs

HR diagram

The hr diagram is used to classify and study the evolution of all stars - absolute magnitude (luminosity) versus their stellar classification (temperature)

2 forces in a star

Gravity and pressure

Pressure due to fusion reactions pushes outwards

Gravity pulls inwards to keep the star in equilibrium

Main element in a star

Hydrogen

What are black holes

Black holes are a region is space were gravity has become so strong that not even light can escape its gravitational pull

How are black holes created

A black hole is the result of a massive star collapsing at the end of its lifecycle.
The core becomes unstable and gravitationally collapses inward upon itself, and the stars outer layers is blown away.
The crushing weight of the constituent matter falling from al sides compresses to a point of zero volume and infinite density.

Edwin Hubble

Life cycle of stars

Facts

Facts are established by experiment or observation, true under scientific conditions, they can be false when retested with better instruments.

Theries

Theories are an explanation for why certain laws and facts exist that can be tested

Laws

Laws are the relationship between two or more things that is based on facts and supported hypothesis

Beliefs

Beliefs are a statement not significantly proven in the same way that facts, laws, hypotheses or theories are

Hypothesis

Hypotheses are educated statements "like if a happened, the b must happen" that can be tested by experiment or observation