Saturday, August 1, 2009

BIG BANG Timeline - Formation of Universe

The Big Bang is the cosmological model of the universe which is the best support of all lines of scientific evidence and observation till date. It is widely accepted scientific theory about the origin of the universe. According to the Big Bang Theory and NASA's "Wilkinson Microwave Anisotropy Probe" (WMAP) data, the universe began sometime 13.7 ± 0.12 Billion years from a cosmic explosion at a single point, and has since been expanded in all directions. It has evolved from a primordial dense and hot state in a finite time long long ago and continues to grow until today. The universe began with a amazing cataclysm that is responsible for creation of space and time, along with all the matter and energy the universe will ever hold. All the space, time, energy, and matter of today's universe came in existence due to Big Bang (Most accepted).

All this happened in a very small fraction of time. Let us see what happened during that time and what is happening till date. I got these data form various websites (NASA, wikipedia and many others..) and summarising as per my understanding.
Here are the timelines from the time when the time start first say Time t=0 .

After t=10-43 seconds
The instant of 10-43 seconds is known as Planck time. At that time the quantum wavelength of the universe was larger than the size of the universe. Amazingly universe had complete symmetry: all four fundamental forces we know today were unified. After this time, symmetry breaks and gravity became a distinct force and could be treated as a separate force from the other three forces, which became the electronuclear force. At the moment of Planck time, the temperature of the universe is estimated to be 1032 Kelvin and the diameter of the observable universe is calculated as 10-33 centimeters which is known as the Planck length. This was the start of the Grand Unified Theory(GUT) era. Here we have the beginning of Quantum theory and classical general relativity.

After t=10-36 seconds
During this time strong forces got separated from the electronuclear forces, resulting three forces: gravity, strong, and electroweak forces. The particles which were involved in the strong force were considerably more massive than the particles which were involved with the other forces. Therefore, the particles with strong forces "condense" quicker than other particles. The strong and the electroweak forces behave exactly similar to matter and antimatter. GUT suggest that when the strong and the electroweak forces were mixed together and acted as a single force, a particle reactions occurred which created more matter than antimatter.

After t=10-35 seconds
Beginning of the Inflationary Epoch: Time between 10-35 seconds and 10-33 seconds. Most of the expansion is presumed to have occurred during this period of time than in the entire period of 13.7 ± 0.12 billion years. It is believed that during this time the universe underwent an extremely rapid exponential expansion. The size of the universe expanded by a factor of approximately 1020 to 1030 during this period. The expansion is thought to have been triggered by the phase transition that happened at the end of the GUT epoch. The rapid expansion of space caused distribution of elementary particles (remaining from the Grand Unification Epoch)very thinly across the universe. However, the huge potential energy of the inflation field was released at the end of the inflationary epoch, repopulating the universe with a dense, hot mixture of quarks, anti-quarks and gluons.

After t=10-33 seconds
During this time the temperature of the Universe reached approximately 1025 K. At that temperature, it was possible for quarks to condense out but possibility for protons and neutrons to prove their existence was impossible. During the Inflationary epoch the quarks appears along with anti-quarks and gluons. Therefore, quarks and anti-quarks annihilated each other to create photons. But quarks were created at a ratio of approximately 109 (1 billion) anti-quarks to 109+1 (1,000,000,001) quarks, which means one free quark per billion to enjoy freely. At that time collisions between particles were too energetic to allow quarks to combine into mesons or baryons.

After t=10-12 seconds
Till this time temperature of the Universe decreased down to 1015 K. Dramatically the diameter of the currently observable universe increases to approximately 1013 meters. The weak force which involved a massive particle condensed and separated from the electromagnetic force which involved a mass less particle. This separated four fundamental forces ( gravitation, electromagnetism, strong interaction and the weak interaction ) we know today.

During t=10-6 seconds to t=0.0001 (10-4) seconds
Hadron Epoch: The temperature of the Universe was approximately 1013K. The lowering temperature allows quark and anti-quark pairs to combine into mesons. After this period quarks and anti-quarks could no longer exist as free particles. The quark-gluon plasma that composed the universe cooled until hadrons, including baryons such as protons and neutrons, can form. Positrons annihilated each other during the hadron epoch. At 0.0001 (10-4) seconds the temperature of the Universe decreased down to approx.. 10 million (1010) Kelvin.

t=1 second to t=10 seconds after the Big Bang
Lepton Epoch: Till this time almost all of hadrons and anti-hadrons annihilated each other and only leptons and anti-leptons were left as dominating mass of the universe. Because the universe was cooling rapidly, very soon all the Leptons and anti-leptons also annihilated each other and only a small residue of leptons left.

t=10 seconds to t=3 minutes after the Big Bang
Nucleosynthesis: The energy of the universe now dominated by photons because all the leptons and anti-leptons were consumed during Lepton Epoch. Nuclear fusion started as the universe was hot enough for nuclear fusion and thus hydrogen nuclei, the first atomic nuclei took birth.

t=3 minutes to t=20 minutes after the Big Bang
After 3 minutes the nucleosynthesis could not continue for long time and stoped around 17th to 20th minute because the temperature and density of the universe had fallen to the point where nuclear fusion could not be continued and heavier nuclei could not formed. At this point the Hydrogen was three times greater than Helium-4 in mass and trace quantity of deuterium and lithium.

t=300,000 years after the Big Bang
Recombination: Till this time the temperature of the Universe decreased approximately to 10,000 Kelvin. As the universe cooled down, the electrons got captured by the ions making them neutral. At this temperature it was easy for hydrogen nuclei to capture electrons and form stable atoms. Once atoms formed, light(photons) and matter stopped constantly interacting with one another, and photons were suddenly able to travel freely. Now the universe became transparent. Scientists refer to this epoch as the "Surface of Last Scattering" light from that period is observed today as the cosmic microwave background(CMB).

References:;; Images taken from Wikipedia


Phil said...

Interesting stuff!

I just purchased a book called "Bang" by Patrick Moore and Brian May (Queen guitarist turned astronomer), which talks about the timeline of the universe and speculates on the end of it. A good read!


Roopesh said...

hey Phil..

Thanks for sharing this ... Let me see if I can get this book..