Q1: Lesson 1.1 | Timeline of the Big Bang

Question 1

This is the closest that current physics can get to the absolute beginning of time, and very little can be known about this period.

Answer 1

planck epoch

Question 2

the four fundamental forces

Answer 2

electromagnetism, weak nuclear force, strong nuclear force and gravity

Question 3

it is hypothesized that the four fundamental forces (electromagnetism, weak nuclear force, strong nuclear force and gravity) all have the same strength, and are possibly even unified into one fundamental force

Answer 3

planck epoch

Question 4

The force of gravity separates from the other fundamental forces (which remain unified), and the earliest elementary particles (and antiparticles) begin to be created.

Answer 4

grand unification epoch

Question 5

Triggered by the separation of the strong nuclear force, the universe undergoes an extremely rapid exponential expansion, known as cosmic inflation

Answer 5

inflationary epoch

Question 6

Triggered by the separation of the strong nuclear force, the universe undergoes an extremely rapid exponential expansion, known as ______________

Answer 6

cosmic inflation

Question 7

As the strong nuclear force separates from the other two, particle interactions create large numbers of exotic particles

Answer 7

electroweak epoch

Question 8

When all the forces of nature finally split off and became separate

Answer 8

electroweak epoch

Question 9

Quarks, electrons and neutrinos form in large numbers as the universe cools off to below 10 quadrillion degrees, and the four fundamental forces assume their present forms.

Answer 9

quark epoch

Question 10

All of the universe’s ingredients were present but the universe was still too hot and dense for subatomic particles to form

Answer 10

quark epoch

Question 11

Quarks and antiquarks annihilate each other upon contact, but, in a process known as baryogenesis, a surplus of quarks (about one for every billion pairs) survives, which will ultimately combine to form matter.

Answer 11

quark epoch

Question 12

Quarks and antiquarks annihilate each other upon contact, but, in a process known as ______________, a surplus of quarks (about one for every billion pairs) survives, which will ultimately combine to form matter.

Answer 12

baryogenesis

Question 13

The temperature of the universe cools to about a trillion degrees, cool enough to allow quarks to combine to form hadrons (like protons and neutrons).

Answer 13

hadron epoch

Question 14

After the majority (but not all) of hadrons and antihadrons annihilate each other at the end of the Hadron Epoch, leptons (such as electrons) and antileptons (such as positrons) dominate the mass of the universe

Answer 14

lepton epoch

Question 15

The temperature of the universe falls to the point (about a billion degrees) where atomic nuclei can begin to form as protons and neutrons combine through nuclear fusion to form the nuclei of the simple elements of hydrogen, helium and lithium.

Answer 15

nucleosynthesis

Question 16

what was the first element

Answer 16

hydrogen

Question 17

The universe cooled down enough for electrons to attach to nuclei for the first time called recombination—this process helped create the universe’s second element—helium

Answer 17

atomic epoch

Question 18

Hydrogen, along with helium atoms dotted the universe with atomic clouds. Within the clouds, small pockets of gas may have had enough gravity to cause atoms to collect. These clusters of atoms formed during this epoch became the seedlings of galaxies

Answer 18

galactic epoch

Question 19

Nestled inside those galaxies, stars began to form. They queued the latest and current stage of the universe’s development,

Answer 19

stellar epoch

Question 20

making this the earliest epoch observable today. I

Answer 20

Recombination/Decoupling