The 6 Days (periods) of Creation - as mentioned in the Qur'an, scientifically understood in the modern age, with proofs:
Did you know that the "Relativity of Time" was announced over 1400 yrs ago
Throughout history, “time” was assumed to apply equally in every imaginable spot in the universe and in every medium. If we consider this conception, we can see the radical change that the Quranic verses brought. The Quran said that, according to circumstances, the “day” concept might equal even up to fifty thousand years. These verses which must have encountered objections have been elucidated in the twentieth century and shed light on important truths.
The theory of relativity is Einstein’s best known discovery. However, many people whose interests are not in any way related to physics are at a loss to understand what this theory signifies. The Quran had already touched on these facts 1400 years ago. Einstein’s theory of relativity has two main divisions, namely the special theory of relativity and the general theory of relativity.
According to Einstein, time would pass more slowly for somebody driving a vehicle at a speed close to the velocity of light. In a medium in which an inhabitant of the earth passes one hundred days, it may take a person fifty days to displace at a speed nearing the propagation speed of light. This finding is the most interesting fact of the relativity theory. Time slows down in direct proportion with speed. Time is therefore a relative conception, as indicated in the Quran. Hours differ and days are conceived differently according to the medium, place and speed involved.
The general theory of relativity deals with gravitational fields and tries to demonstrate that time is slower in the fields of greater gravitation. A man walking on the surface of the sun will see that his clock runs more slowly, as do the biological and anatomical functions and all the motions in terms of his atoms. Recent experiments have corroborated this fact. One of these experiments was conducted in the British National Institute of Physics. John Laverty, researcher, synchronized two clocks indicating the exact time (two clocks of optimum perfection; error of precision in the course of a space of time of 300,000 years would be not more than 1 second). One of these clocks was kept at a laboratory in London; the other was taken aboard an airplane shuttling between London and China. The high altitude at which the aircraft flies is subject to a lower gravitational force. In other words, time was expected to pass at a faster rate aboard a plane in conformity with the general relativity theory. There is not so great a difference in terms of gravity between someone treading upon the earth and someone flying in the air. This difference could only be established by a precision instrument. It was established that the clock aboard the aircraft had a greater speed, one per fifty five billion seconds. This experiment is one of the proofs of the relativity of time. According to the prevailing prejudice, there should not be any difference between the two clocks. This supports the dispelling of prejudices as foreseen in the Quran. Had it been possible to make this experiment on a planet with greater gravitational force, there would be no need for precision instruments to measure the difference, since normal watches could do the job.
THE USE OF THE WORD “DAY” IN THE QURAN
V4- To Him ascend the angels and the spirit in a day the measure of which is fifty thousand years.
70-The Heights, V4 [70 SURAh AL-MAARIJ, V 4]
V5- He regulates all affairs from the heaven to the earth. Then they ascend to Him in a day, the measure of which is a thousand years as you count.
32-The Prostration, V5 [032 SURAH AS-SAJDAH, V5]
Verse 5 of the sura The Prostration and Verse 4 of the sura The Heights not only point to the relativity of time, but give also a clear meaning of the Arabic word “yawm” (which translates to the word - "day") that denotes not only the space of time of one day - which comprises 24 hours - but also a certain period of time. This makes it easier to understand the six “yawm”s mentioned in the Quran (See: 7-The Purgatory, 54; 11-Hud, 7; 10- Jonah, 3; 25-The Distinguisher, 59; 32-The Prostration, 4; 57-Iron, 4.) Before the creation of the universe and the world there was no notion of “day,” a period of 24 hours. Therefore, the six “yawm”s must be understood as six “periods.”
A NOTE TO CHRISTIANS AND JEWS ABOUT "TIME"
This gives a clue to the Jews and Christians for the interpretation of the Biblical account according to which the world was created in six days. Findings in the domain of space physics show that the universe and our world passed through many stages, from a gaseous state to galaxies, to the formation of the atmosphere surrounding the Earth, and of waters and metals. The fact that the Quran refers to the stages that the process of creation went through is also better understood by modern cosmology.
If we remember the stories of creation of ancient Egypt, China and India, we encounter wild fancies such as a universe standing on a tortoise or as an eternally existing entity. None of the past civilizations had made any reference to the stages of this evolution. This message of the Quran contributes to a correct interpretation of Biblical exegeses of the concept of day. The message in the Bible that reads: “And on the seventh day God finished His work that He had done, and He rested on the seventh day from all His work that He had done.”
(Genesis 2, 2) was thus corrected, as fatigue was certainly out of the question for God.
V38- We created the heavens and the earth, and all that lies between them in six days, and no fatigue touched us.
50-Qaf, V38 [50-Sura Qaf, V38]
CONTRIBUTION OF THE RELATIVITY THEORY
Einstein postulated that the concept of time was relative. For Kant time was an innate function of reason. He contended that the perception of time was an a priori category. Einstein’s physics was henceforth the science that integrated time and space, so that, instead of space we had now space-time.
There is something that must not escape attention, however: the perception of time is achieved by the intellect. Since according to our estimation, just as the special relativity theory establishes that velocity makes time relative and the general relativity theory postulates that gravity makes time relative, one should elaborate on “the intellect’s relativity” which posits that the intellect’s perception manner would render the relative perception of time. Like a key that fits the lock, our intellect also has the capacity of perceiving time and the universe. That is (1) time exists in the universe, (2) and the intellect is created with a priori abilities to perceive time and the universe. The two processes are coexistent, just like the coexistence of the world seen by us and the eyes.
It seems to us only fair to add the intellect’s perception factor to Einstein’s concepts relating velocity and gravity and time. Comprehension of time’s relativity will contribute to a better understanding of the Quran. For instance, it is said in the Quran that the dead will think when resurrected that their span on the earth had been very brief. Once time’s relativity has been conceived, the puzzling question of the time to elapse from one’s death till the Day of Judgement will be clear. Such questions for the inquisitive mind that sees the time upon the earth as the only valid time regardless of the attending circumstances will find their answer, once time’s relativity is understood. Given the fact that a deceased person is outside the confines of the temporal dimensions of the earth, the time to elapse after his death, regardless of its actual duration, would be of no consequence.
V45- On the day when He gathers them, it will appear to them as if they had tarried an hour of a day...
10-Jonah, V45 [010 SURAH YUNUS, V45]
V112- He said: “How many years did you stay on earth?”
V113- They said: “We stayed a day or part of a day, ask those who account.”
23-The Believers, V112-V113 [23 SURAH AL-MOMINOON, V112-V113]
ANYONE AMONG US TIRED OF WAITING FOR EONS?
The reason why the fifteen billion years that elapsed from the moment the universe was created until the creation of man was made clear by time’s relativity. In a different context, fifteen billion years may be conceived as one minute or even less. The length of its duration depends on our perception and standpoint.
Scientists, based on the most recent and accurate calculations, assert that approximately fifteen billion years have elapsed since the creation of the universe until this very moment. Is there anyone who feels tired of waiting for eons? The evident answer being in the negative, the time the departed will have to wait as from their decease until resurrection will not cause anxiety in them. Comprehension of time’s relativity renders possible the solution of many problems believed to be beyond the grasp of the intellect.
PROOF FROM NECESSARY VERSUS POSSIBLE BEING
A host of celebrated philosophers like Avicenna (Ibn Sina), Farabi, Taftazani and Jurjani had recourse to this argument in proving God’s existence. They asserted that all the possible creatures upon the earth could not exist by themselves as they owed their existence to a Creator. “The created” requires a Creator while God, “the Self-Existent” (whose existence is a necessity) does not need a creator. The created is a product of causality; their existence or non-existence are within the confines of possibility. To think of the non-existence of the existent poses no contradiction. However, this does not hold true for the Self-Existing, God; otherwise the contradiction would be evident. Philosophers like Leibniz argued in like manner the principle of “Sufficient Reason.” According to him, the universe is made of possible beings. The universe itself is a possibility. If we try to trace back the chain of causality (which is impossible) until the infinite this would not explain the universe. Yes, the universe is a possibility but requires a Sufficient Reason outside its confines. To allege that the reasons may be traced back to the infinite would mean that we were created after eternity. But since eternity is endless there would be no question of any lapse of time after eternity; if there has been a chain of causality, it would necessarily follow that it had had an end. If there had been a chain of causality that came to an end, it would prove the existence of a “first cause.” There may be persons who would find the existence of a first cause difficult to grasp. On the other hand, an eternal chain of causes would be a self-contradiction.
Absurd and incomprehensible are not the same thing. For instance, the structure of a space-shuttle may be incomprehensible for us, but we cannot deny its existence. The number 5 cannot be higher than the number 10; that is absurd. As the contrary is absurd (that the eternal chain of causes has led to this point), the existence of a first cause is a necessity (although there are those who contend that this argument is “beyond comprehension”).
What I propose to do is to reformulate the approaches of a series of thinkers from Avicenna to Leibniz in the light of scientific data obtained in the twentieth century in a richer and more scientific context. Findings related to the relativity theory may be used for this end. That the perfect use of time existing only in relative terms in the universe, in the formation of the universal targets, can only be grasped by the existence of an Absolute and Indispensable Regulator, that the existence of time can only be explained in a satisfactory way by the Cause behind the creation of time, that the harmony existing between time and intellect can be imagined to exist by the presence of a Regulator outside the confines of time and intellect and that even time is a possibility depending on a Creator should be integrated for use with the explanation of the “proof from necessary versus possible beings.”
V81- ]And He shows you His signs: Then which of the signs of God will you deny?
40-The Believer, V81[040 SURE GAFIR, V81]
Looking at the works of Ibn Sina, Farabi, Taftazani and Jurjani as well as the works of Einstein, Newton, etc - we can see quite clearly that when Allah mentions in the Quran, the following:
[7:54] Your Lord is the one GOD; who created the heavens and the earth in six days,* then assumed all authority. The night overtakes the day, as it pursues it persistently, and the sun, the moon, and the stars are committed to serve by His command. Absolutely, He controls all creation and all commands. Most Exalted is GOD, Lord of the universe.
[11:7] He is the One who created the heavens and the earth in six days—*and His (earthly) domain was completely covered with water—**in order to test you, to distinguish those among you who work righteousness. Yet, when you say, "You will be resurrected after death," those who disbelieve would say, "This is clearly witchcraft."
[10:3] Your only Lord is GOD; the One who created the heavens and the earth in six days, then assumed all authority. He controls all matters. There is no intercessor, except in accordance with His will. Such is GOD your Lord. You shall worship Him. Would you not take heed?
[25:59] He is the One who created the heavens and the earth, and everything between them, in six days, then assumed all authority. The Most Gracious; ask about Him those who are well founded in knowledge.
[32:4] GOD is the One who created the heavens and the earth, and everything between them in six days, then assumed all authority. You have none beside Him as Lord, nor do you have an intercessor. Would you not take heed?
[57:4] He is the One who created the heavens and the earth in six days,* then assumed all authority. He knows everything that enters into the earth, and everything that comes out of it, and everything that comes down from the sky, and everything that climbs into it. He is with you wherever you may be. GOD is Seer of everything you do.
These are periods of measurement, in time - and time wasn't always a constant.
For example, we know from modern cosmology that time moves differently in different parts of the galaxy, and universe. For example, an earth day is 24 hours, but how long is a Mars day? or a Jupiter day? When "space" affects "time" - we understand that "time" itself is not a constant. So, therefore a day cannot be a constant according to "time" and "space", and the perception of time is wholly dependant on the witnessing of its passing.
To my knowledge, no human beings saw the universes creation... and so, the 6 periods mentioned in the Quran and the bible as "days" are indeed days (periods of time) but not in the way we measure them today. Nope. A Day by the reckoning of the creator is sometimes 1000 years, sometimes 50,000 years and sometimes even longer - dependant on what action is being referred to in the Quran.
is it all relative? of course... Einstein himself had no problem with it.
SIX DAYS OF CREATION
by Ibrahim B. Syed, Ph. D.
Islamic Research Foundation International, Inc.
7102 W. Shefford Lane
Louisville, KY 40242-6462, USA
With regard to the creation of the universe (heavens and the earth) Allah (SWT) says in the Qur'an:
Your Guardian Lord
Is God, Who created
The heavens and the earth (universe)
In six Days,
The Qur'an 7:54 / 32: 4
The literal translation gives the impression that the universe was created in six Days. The Arabic word "Yaum" is translated as Day. Actually a 'day' of the people living on earth is the time interval between each sunrise. During this time the earth makes one complete rotation around its axis, while moving in an orbit around the sun (which is a star).
In this verse Allah (SWT) is referring to the conditions, which existed before the sun or earth, were created. Hence the 'six days' should not be interpreted in terms of earth days. For Allah "yaum" is equal to billions of years or as short as one hundredth of a second or one atto-micro second (10-18 X 10-6 = 10-24 second).
The relativity of time is mentioned in the Qur'an Hakeem (The Book of Wisdom) in several verses. It is pertinent here to quote Abdullah Yusuf Ali, the most popular translator of the Noble Qur'an in the English language with commentaries. In note 1031 he says, "The creation in six Days is of course metaphorical. The " Days of God" refer not so much to time as to the growth in us of a spiritual sense, a sense of sin and a sense of God's Mercy. In Surah, 22: 47, we are told that a Day in the sight of God is like a thousand years of our reckoning and in Surah, 70: 4; the comparison is with 50,000 years of our (earth) years. In the history of our material earth, we may reckon six great epochs of evolution."
Hence the concept of time is relative. The meaning of "Yaum" includes day, period of time, interval of time, age, era, epochs of evolution or Time Frame.
The following article describes the creation of the universe in six periods of time or "Time Frames". This description is based on a theory of the early universe, which is popularly known by astronomers as the "standard model." It is more or less same thing as the "Big Bang" theory except that it contains the detailed recipe for the contents of the universe.
At the end of the article a Glossary of technical words is provided so that the readers may refer to it in order to understand the meaning of the word.
At the beginning, time was zero and space was zero and the temperature was infinite. Einstein showed through his famous equation (E = mc2) that mass can be converted into energy and energy can be converted into mass. Heat is energy, and from energy particles of mass could be produced. Above a threshold temperature of one billion degrees Kelvin (0° Celsius is equal to 2730 Kelvin), the universe would have contained a large number of particles called pi mesons. Their mass is about one-seventh that of a nucleon (proton or neutron). Nucleon is a particle that exists in the nucleus of an atom. A proton is a positively charged nucleon, whereas a neutron is slightly heavier than the proton but is electrically neutral. Unlike other particles, pi mesons interact very strongly with each other and with the nucleons. The interaction of pi mesons with the nucleons or nuclear particles is responsible for the nuclear or attractive force that exists in the nucleus of an atom.
The behavior of matter at super-high temperature is very difficult to predict. Hence the interpretation of the creation of the universe starts about one-hundredth of a second after the beginning (Big Bang) and the temperature was one hundred billion degrees Kelvin (0° Celsius is equal to 2730 Kelvin).
At this time the temperature of the universe is one hundred billion degrees Kelvin (1011 °K). It is filled with particles and radiation, which cannot be differentiated. The particles, which are continually being created out of pure energy, are colliding with each other very rapidly. Although the universe is expanding rapidly, the universe appears to be in a state of thermal equilibrium. The contents of the universe are subject to the laws of statistical mechanics. The temperature is extremely hot (1011 °K) and the conserved quantities of particle physics such as charge, lepton number, baryon number-are extremely small or zero.
The particles that are present abundantly are the electron (the negatively charged particle that flows through wires in electric currents and makes up the outer parts of all atoms and molecules in the present universe) and positron (antiparticle of electron which is a positively charged particle with precisely the same mass as electron). In the present universe positrons are found only in high-energy laboratories, in some kinds of radioactivity, and in violent astronomical phenomena like cosmic rays and supernovas, but in the early universe the number of positrons was almost exactly equal to the number of electrons, the massless particles- the photons, neutrinos and antineutrinos (antiparticle of neutrino). Neutrinos are ghostly particles with no mass or electric charge. At this time the universe is extremely dense and even the neutrinos, which can travel through the earth or through lead bricks without being scattered, are in a state of thermal equilibrium with electrons, positrons, and photons by colliding with them rapidly and with each other. They are behaving just like so many different kinds of radiation. The energy density is calculated to be 21 X 1044 electron Volts per liter.
This is equivalent to a mass density of 3.8 billion kilogram per liter or to express in simple term's equivalent to 3.8 billion times the density of water under normal earth conditions. Nobody has any concept of what this huge density means. Suppose Mount Everest was made of matter this dense, its gravitational attraction would destroy the earth. At this time the universe is filled with light.
The universe on the 'first day' is rapidly expanding and cooling. There are a small number of nuclear particles (nucleons) at this time. About one nucleon (proton or neutron) for every one billion (109) photons or electrons or neutrinos. The neutron is slightly heavier than the proton. The few neutrons or protons are colliding with the abundant electrons, positrons, and so on. As a result of these collisions a proton is converted into a neutron and vice versa. The reaction can be written as:
Proton + antineutrino = neutron + positron (vice versa)
Neutron + neutrino = proton + electron (vice versa)
There are almost exactly the same number of neutrinos and anti-neutrinos, the same number of electrons and positrons, so that the transition from neutron to proton is as fast as the transition from proton to neutron. Because of equilibrium the number of neutrons is equal to the number of protons on the 'first day.' These nucleons are not yet bound into nuclei and any complex nuclei formed are destroyed as soon as they are formed.
One is tempted to ask the question how large was the universe on the 'first day.' Unfortunately no one has the answer and this question has no meaning. If one shows that the universe is infinite now, then one can argue that the universe was Infinite then (at the time of 'first day), and will always be Infinite. On the other hand it is possible that the universe now has a finite circumference, which is estimated to be about 125 billion light years. This estimate is based on the present value of the Hubble Constant. By taking the ratios of the temperature then (1011 °K) to the present temperature (3° K), the circumference of the universe on the 'first day' is calculated to be about four light years (A light-year is the distance traveled by light in one year at the rate of 300 million kilometers per second). The details of the story of cosmic evolution (birth and formation of the universe) in the beginning do not depend on whether the circumference of the universe was infinite or had only a few light years.
Since the 'first day' only eleven hundredths of a second (0.11 sec.) have elapsed. The temperature of the universe has come down (cooled) to 30 billion degrees Kelvin (3X1010 °K). Qualitatively nothing has changed- the contents of the universe are the same such as protons, neutrons, electrons, positrons, neutrinos, antineutrinos and photons, -all in thermal equilibrium. The energy density has dropped to about 30 million times the energy density contained in the rest mass of water. The expansion time of the universe has now lengthened to about two-tenths of a second (0.2 second). The few nucleons (neutrons or protons) are not bound into nuclei, but with the cooling of temperature it is now significantly easier for the heavier neutrons to transform into lighter protons than vice versa. The ratio of neutrons to protons or nuclear particle balance has shifted to one-third neutrons and two-thirds protons.
Since the 'first day' a little over one-second (1.09 seconds) have elapsed. The temperature of the universe is now ten billion degrees Kelvin (1010 °K). The decreasing density and temperature have caused the neutrinos and antineutrinos to behave like free particles and they are no longer in thermal equilibrium with the electrons, positrons or photons. This is called the "decoupling" of the neutrinos and they expand freely. They do not play any active role in the formation of the universe, except that their energy will continue to provide part of the source of the gravitational field of the universe.
The energy density is now reduced to a mass density of 380,000 times that of ordinary water. The temperature of the universe is twice the threshold temperature of electrons and positrons. The electrons and positrons interact with each other to annihilate more rapidly than they can be created out of radiation (energy). The temperature of the universe is still too hot for neutrons and protons to be bound into atomic nuclei for any appreciable length of time. The cooling temperature has now allowed the neutron-proton balance to shift to one-quarter neutrons and three-quarter protons.
Since the 'first day' about 14 seconds have elapsed. The temperature of the universe is now 3 billion (3 X 109 °K) degrees Kelvin. The electrons and positrons are beginning rapidly to disappear as major components of the universe. The neutrinos are about 8 percent cooler than the electrons, positrons, and photons. Here afterwards the temperature of the universe means the temperature of the photons.
The temperature is cool enough for the formation of stable nuclei such as helium (4He), however this does not occur immediately. Now, ordinary helium (He4) is a tightly bound nucleus. On the other hand the isotope (an atom having the same number of protons but different number of neutrons) of hydrogen, tritium (3H), and an Isotope of Helium- helium-3 (3He) are much less tightly 2 bound, and heavy hydrogen or deuterium (2H) is especially loosely bound. (It requires about one-tenth as much energy to pull a deuterium nucleus (which contains one proton and one neutron) apart as to pull a single nucleon out of helium nucleus containing two protons and two neutrons). On the 'fourth day' with a temperature of three billion degrees Kelvin, nuclei of deuterium (heavy hydrogen) are blasted apart as soon as they form and there is no chance for the formation of heavier nuclei. Neutrons continue to be transformed into protons, but at a much slower rate than before. The neutron-proton balance is about one-fifth neutrons to four-fifth protons.
Since the 'first day' three minutes and two seconds have elapsed. The temperature of the universe is now one billion degrees Kelvin (109 °K), just about 70 times hotter than the temperature at the center of the sun. The main components of the universe are now photons, neutrinos, and antineutrinos as the electrons and positrons have mostly disappeared. When electron-positron pair annihilate energy is released which increases the temperature of the photons by 35 percent more than that of the neutrinos.
The temperature of the universe is cool enough so that the nuclei of normal helium (Helium-4), helium-3, and tritium hold together. One should remember that when a neutron is free (not bound in the nucleus) it decays after 920 seconds or about 15 minutes and becomes a proton. The collision between neutrons and protons with electrons, neutrinos, and their antiparticles have now come to a stop, but the decay of the free neutron is beginning to be important. The neutron-proton balance is now one-seventh neutrons and six-sevenths protons. This period is called "era of nucleosynthesis", as neutrons are rapidly assembled into helium nuclei, and the neutron-proton ratio is frozen at the value it has at that time.
Since the 'first day' more than half-an-hour or 34 minutes and 40 seconds have elapsed. The temperature of the universe is now 300 million degrees Kelvin or 21 times hotter than the temperature at the center of the sun. Except for the small excess of electrons required to balance the charge of the protons, the electrons and positrons are now completely annihilated. The energy density of the universe is now equivalent to a mass density one-tenth that of ordinary water; of this one-third is in the form of neutrinos and antineutrinos and two-third is in the form of photons. Nuclear processes have ceased, so that the nucleons are mostly either bound into helium nuclei or are free protons (nuclei of hydrogen atoms). There is one electron for each free or bound proton. Since the universe is too hot, stable atoms cannot hold together.
For about one million years, the universe goes on expanding and cooling without anything happening. At that time the temperature would have cooled to the point where electrons and nuclei can form stable atoms. Due to lack of free electrons in the contents of the universe, the universe becomes transparent to radiation. This era is known as the "Decoupling Era" - decoupling of matter and radiation. The electron and-protons combine to form hydrogen and helium gases. The resulting gas would begin under the influence of gravitation to form clumps, which would ultimately condense to form galaxies and stars of the present universe. After another 10 billion years later intelligent beings will emerge to postulate the story of the origin of the universe.
ANTIPARTICLE: A particle with the same mass and spin as another particle, but with equal and opposite electric charge, baryon number, lepton number, and so on. To every particle there is a corresponding antiparticle, except that certain purely neutral particles like the photon and pi-zero meson are their own antiparticles. The antineutrino is the antiparticle of the neutrino; the antiproton is the antiparticle of the proton; and so on. Antimatter consists of the antiprotons, antineutrons, and antielectrons or positrons.
BARYON NUMBER: It is the total number of baryons (neutrons, protons, hyperons) present in a system, minus the total number of antibaryons.
CHARACTERSITIC EXPANSION TIME: Reciprocal of the Hubble constant. Roughly, 100 times the time in which the universe would expand by one percent.
DENSITY: The amount of any quantity per unit volume. The mass density is the mass per unit volume. The energy density is the energy per unit volume; particle density is the number of particles per unit volume.
ELECTRON: The lightest massive elementary particle. All chemical properties of atoms and molecules are determined by electrical interactions of electrons with each other and with the atomic nuclei.
ELECTRON VOLT: A unit of energy, convenient in atomic physics, equal to the energy acquired by one electron in passing through a voltage difference of one volt.
GALAXY: A large gravitationally bound cluster of stars, containing up to 1012 solar masses. A galaxy contains 200 to 300 billion stars.
HUBBLE CONSTANT: It is the ratio of velocity of recession of moderately distant galaxies to their distance, and is denoted H or Ho.
LEPTON: A class of particles, which do not participate in the strong interactions, these are the electron, muon, and neutrino.
LIGHT YEAR: The distance that a light ray travels in one year, equal to 9.4605 X 1012 km
MESONS: A class of strongly interacting particles: pi, K, rho mesons with zero baryon number
PHOTON: The particle associated with a light wave.
PROTON: The positively charge particle found along with neutrons in atomic nuclei.
RECOMBINATION: The formation of helium and hydrogen atoms at a temperature around 3000o K
REST ENERGY: The energy of a particle at rest, which would be released if all the mass of the particle could be annihilated. Given by Einstein's formula E = mc2.
STRONG INTERACTIONS: Responsible for the nuclear forces, which hold protons and neutrons in the atomic nucleus.
THERMAL EQUILIBRIUM: A state in which the rates at which particles enter any given range of velocities, spins, and so on, exactly balances the rates at which they leave. Any physical system will reach thermal equilibrium after a long time if left undisturbed.
THRESHOLD TEMPERATURE: It is the temperature above, which a particle can be freely created out of thermal radiation. It is the rest energy divided by Boltzmann's constant.