 | Timeline of the Big Bang: Encyclopedia II - Timeline of the Big Bang - Planck Epoch
Timeline of the Big Bang - Planck Epoch
The Planck Epoch covers the time from 10-43 to 10-35 seconds after the Big Bang. The temperature during this epoch is estimated to decrease from 1032 K to 1027 K.
10-43 seconds
A length of 10-43 seconds is known as Planck time. At this point, the force of gravity separated from the other three forces, collectively known as the electronuclear force. A complete theory of quantum gravity such as superstring theory is needed to understand these very early events; however the present understanding of cosmology in string theory is very limited. The diameter of the currently observable universe is theorized as 10-35 m which is known as the Planck length.
10-36 seconds
Separation of the strong force from the electronuclear force, leaving two forces: electromagnetic, and electroweak forces. The particles which are involved in the strong force are considerably more massive than the particles which are involved with the other forces and so are believed to "condense" out earlier.
The Universe undergoes hyper-inflation, where expansion is greatly speeded up.
The Grand Unification Epoch covers the time from 10-35 to 10-12 seconds after the Big Bang. The temperature during this epoch is estimated to decrease from 1027 K to 1015 K.
10-35 seconds
For the period of time between 10-35 seconds and 10-33 seconds, it is believed that the size of the universe expands many orders of magnitude. Postulating the existence of inflation solves a number of problems which are described in cosmic inflation.
This period is also very important for the existence of matter in the universe. Individually, the strong and the electroweak forces behave exactly the same way toward matter and antimatter, which means that there is no opportunity after this time for more matter to be created than antimatter. The electromagnetic and the electroweak forces are mixed and act as a single force. Grand unification theories suggest that when this is the case, it may be possible to have particle reactions which create more matter than antimatter.
10-33 seconds
The temperature of the Universe is approximately 1025 kelvins. The Quark-Antiquark Freezeout begins and lasts until 10-5 seconds. At these temperatures, quarks are able to condense out but the temperatures are still too hot for protons and neutrons to exist.
Birth of quarks, which appear in particle-antiparticle pairs. Quarks and anti-quarks annihilate each other to create photons, but quarks are created at a ratio of approximately 109 (1 billion) anti-quarks to 109+1 (1,000,000,001) quarks, resulting in one quark per billion matter-antimatter interactions. The mechanism causing this asymmetry, called baryogenesis is under active research and different theories are offered.
Free quarks multiply rapidly.
The four forces of the Universe differentiate themselves; gravity, the strong force, the weak force, and the electromagnetic force. The Universe starts off with the Grand Unified Force, which then differentiates into gravity and the electronuclear force. The electronuclear force, in turn, differentiates into the strong force and electroweak force.
Finally, the electroweak force differentiates into the weak force and the electromagnetic force.
The Electroweak Epoch covers the time from 10-12 to 10-6 seconds after the Big Bang. The temperature during this epoch is estimated to decrease from 1015 K to 1013 K.
10-12 seconds
The diameter of the observable universe increases to approximately 10-13 meters. The weak force, which involves massive particles, condenses and separates from the electromagnetic force, which involves a massless particle, leaving us with the four separate forces we know today.
Note:Currently, particle accelerators can reproduce the conditions that cause these two forces to act the same thereby reproducing the general conditions of the Universe during this epoch, but no farther. No one has experimentally recreated the high-energy states necessary for the electroweak and the strong forces to merge into the electronuclear force.
Quarks, gluons, and leptons begin to form. Battered by radiation and unable to combine into heavier particles, they float about in a quark-gluon plasma.
The Hadron Epoch covers the time from 10-6 seconds to 10-3 seconds after the Big Bang.
10-6 seconds
Electrons and positrons annihilate each other during the hadron epoch.
10-5 seconds
Quarks combine to form protons and neutrons. The lowering temperature allows quark/anti-quark pairs to combine into mesons. After this period quarks and anti-quarks can no longer exist as free particles.
Some scientists theorize that primordial black holes first appeared during this period.
10-4 seconds
The existence of antimatter is cancelled out, as lepton/anti-lepton pairs are annihilated by existing photons. Neutrinos break free and exist on their own.
The Lepton Epoch covers the time from 10-3 seconds to 1 second after the Big Bang. Hydrogen nuclei begin to form, and the process of nuclear fusion begins as more elements such as helium form. Baryogenesis occurs (not to be confused with genesis of baryons).
1 second after the Big Bang
Nuclear fusion begins to occur as the universe is now cool enough for atomic nuclei to form and still hot enough for them to collide to form heavier chemical elements.
The Epoch of Nucleosynthesis covers the time from 1 second to 3 minutes after the Big Bang. The temperature during this epoch is estimated to decrease from 1010 K to 109 K.
Three minutes after the Big Bang, the universe is too cool for nuclear activity to continue, and these reactions stop. At this point the universe's nuclei consist of about 75% hydrogen, 25% helium and trace amounts of deuterium, lithium, beryllium, and boron. Elements heavier than this do not have time to form before nuclear reactions stop. By looking at conditions between 1 second and 3 minutes after the Big Bang, one can predict the elemental abundance of the Universe. These predictions are broadly in agreement with observations.
Epoch of Recombination
379,000 years after the Big Bang
The temperature of the Universe is approximately 3000 kelvins. At this temperature hydrogen nuclei capture electrons to form stable atoms. This event known as recombination is particularly significant because free electrons are effective at scattering light, which is why fire is not transparent, while hydrogen atoms will allow light to pass through.
This implies that this is the time at which space becomes transparent to light, since photons no longer interact strongly with atoms. This means that what we normally think of as matter and what we normally think of as energy become separate.
The light from the moment at which the universe became transparent has been redshifted to radio waves and makes up the cosmic microwave background.
Light energy from the initial expansion of the Universe stretches out and weakens to the point where matter finally dominates in influence (this is the generally agreed-to end of the Big Bang era). Telescopes are not able to see further back in time than this time because before this time, the Universe was too hot for atoms to be stable. The matter existed as ions because the electrons had too much energy to stay in atoms. The ions caused the Universe to be opaque to light because free electrons can absorb any wavelength of light. Once the universe cooled enough for the combination rate of atoms to be greater than the rate of ionization, the electrons and light nuclei formed atoms. The electrons in atoms can only absorb specific wavelengths of photons. Photons of other wavelengths pass by without being absorbed. This made the universe transparent to most wavelengths.
Since they cannot get images from before deionization, scientists must use particle accelerators and theoretical physics to infer what occurred indirectly. The most direct evidence scientists can measure from the Big Bang is the cosmic microwave background radiation that is uniformly pervasive throughout the Universe. It is thought this background radiation is actually a snapshot of the early Universe and provides the best evidence of the creation of matter during the early epochs.
Other related archives%, (13.7 ± 0.2) x 109 years ago, 1019 seconds, Age, Baryogenesis, Big Bang, Big Bang theory, Big Crunch, Big Rip, Black Holes, Bogdanov Affair, Earth, Electrons, Era, Exponential timeline, Galaxy formation and evolution, Geologic time scale, Geologic timescale, Grand Unified Force, Grand Unified Theory, Grand unification theories, Graphical timeline of our universe, Hawking radiation, Heat death of the Universe, Heat death of the universe, History of astronomy, History of chemistry, History of physics, Hubble Space Telescope, Hubble's law, Hydrogen, K, Light, Milky Way, NASA, Neutrinos, Neutron stars, Nucleosynthesis, Planck time, Planets, Quark stars, Quarks, Reionization, Stephen Hawking, Telescopes, Timeline of evolution, Ultimate fate of the universe, Universe, White dwarfs, Wilkinson Microwave Anisotropy Probe, accelerate, antimatter, argon, asteroids, atom, atoms, baryogenesis, baryonic matter, beryllium, black hole, black holes, boron, brown dwarfs, chemical elements, comets, cosmic inflation, cosmic microwave background, cosmic microwave background radiation, dark energy, deuterium, diameter, electromagnetic force, electrons, electronuclear force, electroweak force, energy, epochs, existence, expansion, explosion, fate, fire, forces, fusion, galaxies, galaxy, gamma radiation, gas, general relativity, gluons, gold, gravitational, gravitational singularity, gravity, hadron, half-life, helium, hydrogen, hyper-inflation, infinite, lepton, leptons, light, light years, lithium, luminous, m, mathematical, matter, mesons, metaphysics, microwave background radiation, multiverse, neutrons, now in principle observe, nuclear fusion, nuclei, opaque, orbits, oscillatory universe, particle, particle accelerator, particle accelerators, particles, past, philosophy, photons, planetoids, planets, positrons, primordial black holes, proton decay, protons, quantum, quantum gravity, quark-gluon plasma, quarks, quasars, radio waves, recombination, redshifted, religion, scientific theory, scientists, seconds, singularity, solar nebula, space, sphere, star, stars, steady state, string theory, strong force, supermassive black holes, supernova, superstring theory, telescopic observations, temperature, theoretical physics, theories, theory, time, timeline, wavelength, weak force
 Adapted from the Wikipedia article "Planck Epoch", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki |
