Eras

Question 1

Singularity

Answer 1

When the density of the universe was concentrated in a very small volume; there was no distinction between space and time.

Question 2

Planck Epoch (0 - 10^-43)

Answer 2

All the forces were united in one grand force.

Question 3

GUT Era (10^43 - 10^-36)

Answer 3

The four forces were united and at the end of planck era gravity separated. GUT era ended when the strong force separated.

Question 4

Inflation

Answer 4

A period of rapid expansion. Inflation solved the horizon problem which asked why the CMB radiation is uniform throughout the universe, and the flatness problem which asked why the universe has zero curvature (because inflation flattened out space with its rapid expansion).

Question 5

Electroweak Era

Answer 5

After inflation era. Four forces became distinct

Question 6

Nucleosynthesis Era

Answer 6

Protons and neutrons fused producing heavier nuclei but radiation was so intense that they dissociated. Density then dropped and fusion no longer took place. About 75% of the mass of matter ended up in Hydrogen and 25% in Helium.

Question 7

Nuclei era

Answer 7

Lasted 380,000 years. At 380,000 years the temperature reached 3000 K and stable atoms were able to form. The Universe first became transparent as photons were able to escape.

Question 8

Decoupling era

Answer 8

Universe expansion led to photons ceasing to interact with electrons and therefore, decouple. Transparency of the universe.