Origin Of The Universe [Breakdown By Seconds, Minutes And Hours]
Tags: Universe, Science, Astrophysics, Physics, Cosmology

Source: Daily Express

Uncountable myths and theories have tried to explain the origin and fate of the universe, but there is one explanation which is widely accepted — The Big Bang Theory.

The Big Bang theory was a result of the observation that all other galaxies are moving away from our own at great speed in all directions as if an ancient explosive force had propelled them.

A Belgian priest named Georges Lemaître first suggested that the universe began from a single primordial atom. His idea instantly received a significant boost from Edwin Hubble’s observations that interpreted as showing that stars and galaxies are moving away from Earth in every direction. Fittingly, the velocities of recession increase in proportion with distance and this discovery has been confirmed by repeated measurements since Hubble’s time. These findings imply that the universe is expanding.

Source: Nap.edu

At the Big Bang itself, the universe is thought to have had zero size, and so to have been infinitely hot. But as the universe expanded, the temperature of the radiation decreased.

However, the radiation did not decrease immediately after the big bang. It took the universe years to cool down, and there is a timeline associated with it.

Let’s have a look at the timeline:

What happened 1 second after the Big Bang?

After one second, the temperature would have fallen to about ten thousand million degrees. This is about a thousand times the temperature at the centre of the Sun. Temperatures as high as these are reached in Hydrogen bomb explosions.

As the universe continued to expand, and the temperature to drop, the universe’s fundamental particles started to form. At this stage, it was still so hot that these particles hadn’t yet settled for the subatomic particles that we know today as neutrons, protons and electrons. Radiation at this time was so intense that colliding photons could form pairs of particles made of matter and antimatter. It’s thought that the early universe contained equal amounts of matter and antimatter.

Antimatter is defined as a material composed of the antiparticles of the corresponding particles of ordinary matter.

Source: Popular mechanics

What happened 100 seconds after the Big Bang?

After a hundred seconds, the temperature would have fallen to one thousand million degrees, the temperature inside the hottest stars. At this temperature, the protons and neutrons would not have sufficient energy to escape the attraction of the strong nuclear force. They would have started to combine together to produce the nuclei of atoms of deuterium. The deuterium then would have combined with more protons and neutrons to make helium nuclei.

What happened 3 minutes after the Big Bang?

The protons and neutrons would have assembled into hydrogen and helium nuclei. By mass, hydrogen and helium were 75% and 25% of the early universe’s matter respectively.

What happened a few hours after the Big Bang?

After a few hours of the Big Bang, the production of helium and other elements would have stopped. After the next million years or so, the universe would have just continued expanding, without anything substantial happening. The regions which were slightly denser than average, would not have expanded as expected because of the dominance of gravitational force. This would have eventually caused to stop expansion and start to recollapse.