Evolution of the Universe

Question 1

Planck

Answer 1

Big Bang
Universe came into existence

Question 2

GUT (Grand Unification)

Answer 2

All forces indistinguishable
All acted the same
As Universe cooled,

Question 3

Inflation

Answer 3

Universe expands at unprecedented rate

Question 4

Electroweak

Answer 4

EM interaction separated from the weak interaction giving us the 4 fundamental interactions
Gravity began to control the expansion of the Universe

Question 5

Quark

Answer 5

Quarks, leptons and their anti-particles formed

Question 6

Hadron

Answer 6

Universe cooled sufficiently for quarks and anti-quarks to combine and form protons, neutrons and their anti-particles

Question 7

Lepton

Answer 7

Universe cooled to the point where no new lepton/anti-lepton pairs were created
Neutrinos and anti-neutrinos no longer interacted with protons ad neutrons, so the Universe because transparent to neutrinos

Question 8

Photon

Answer 8

After Lepton era, Universe dominated by photons. Interacted with protons, electrons and eventually nuclei (radiation era)

Universe cooled to the point where protons and neutrons began fusing to form Helium and deuterium nuclei, using up all spare neutrons

Soon fell to point where fusion couldn’t continue

Question 9

Matter-dominated

Answer 9

Hydrogen and helium nuclei captured electrons into orbits around them to stabilise
Photons no longer interacted with charged particles. Universe became transparent to them
First stars formed
Heavy elements created in supernova explosions
Sun and Solar System formed

Question 10

Star Luminosity

Answer 10

The energy radiated by an object per second

Question 11

Star Brightness

Answer 11

The energy received per square metre per second