Astrophysics

Universe vs Galaxy

Collection of billions of galaxies vs Collection of billions of stars

Difference in orbits of comets, moons and planets

Comets - Highly elliptical

Moons - Circular

Planets - Slightly eliptical

Life cycle of a low mass star

Nebula - cloud of gas and dust

Protostar - gravitational force pulls particles closer together

Main sequence - nuclear fusion occurs, equilibrium

Red giant - hydrogen runs out so fuses helium

White dwarf - helium fusion finishes

Black dwarf

Life cycle of a high mass star

Nebula - cloud of gas and dust

Protostar - gravitational force pulls particles closer together

Main sequence - nuclear fusion occurs, equilibrium

Red supergiant - hydrogen runs out so fuses helium and it expands

Supernova - Core of star collapses and explodes

Neutron star - dense body and collapses into black hole

Black hole - Extremely dense point that even light can't escape

The Big Bang theory states that

- Universe started with an explosion (Big Bang)

- All matter and energy was concentrated at a single point

- The explosion caused the universe to expand from this single point

How does Redshift provide evidence for the Big Bang Theory

- Since the light observed from distant stars has red-shifted this shows that the universe is expanding

- the expansion can be extrapolated back to its point of origin

How does CMBR give evidence for the Big Bang Theory?

- Cosmic Microwave Background Radiation is observed at all points in space around the whole Earth

- EM Radiation was produced shortly after the Big Bang and now been red shifted into the microwave region