The Big Bang occurred an estimated 13.7 billion years ago.

It was not a giant explosion into existing space, as many people are lead to believe. Rather, it was the very rapid expansion of the fabric of the Universe known as "spacetime." The irony is that the "Big Bang" was neither big nor loud by conventional standards.

Prior to the Big Bang, our Universe existed in an extremely small, hot and dense state known as a singularity. We don't know how or why the Universe came into existence, but that is not what the Big Bang is about. Instead the Big Bang was the event that happened immediately after this singularity somehow came into being.

Anyway, the Universe was so hot that the four fundamental forces we know of today (gravity, electromagnetism, the strong and weak nuclear forces) behaved the same way and functioned as one "Superforce." Suddenly, for reasons yet unknown, gravity split off from this force, triggering the Universe's extremely rapid expansion. In less than a second, the Universe grew from smaller than an atom to the size of the Solar System, and expanding ever larger.

As the Universe grew it became cooler and less dense as energy spread out. Energy was converted into quarks, electrons, and other subatomic particles, which further came together to form atomic nuclei. Eventually the Universe cooled down enough for electrons to become bound to the nuclei forming the first true atoms. The Universe was now filled with vast clouds of hydrogen and helium, the lightest and most abundant elements. These clouds would eventually coalesce through gravity to form stars and galaxies.

The question was, how could the Universe be so tiny, smaller than an atom? Einstein's theory of general relativity discovered that spacetime is collapsible, and can actually be warped and folded around itself. To visualize inflation, picture a paper map crumpled into a tiny ball. Then imagine the map is suddenly pulled out in all directions so that it unfolds and becomes a flat sheet. That's what the Big Bang was: the expansion and flattening of spacetime.

There is abundant evidence that the Big Bang occurred and it fits the full range of observations made by astronomers. Most commonly mentioned are the expansion of the Universe and the cosmic microwave background. For the full range of evidence, see the related link below. Today the Big Bang theory is the most widely accepted model in the scientific community for the early development of the Universe.

For more info see the related questions and links

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An Alternative Theory -- Steady State Theory

There is also another Theory, which Maxwell, Einstein, Hoyle, and hundreds of other Astrophysicists and Astronomers believed in wholeheartedly, known as the Steady State Theory. A theory which you probably have never heard of in your many years of public education.

In the Big Bang Theory all known laws of physics have to be thrown out, and a new Superforce, Exotic Matter, Dark Matter, and dozens of Alternate Dimensions had to be invented to make the theory work properly. And even with throwing out all of the known laws of physics - it still does not work, because the Universe is not old enough to explain the universal standardized temperature throughout the universe. In short: the temperature should not be this uninformed, or this cold.

In the Steady State Theory the Universal Primordial Atom (the singularity) was not a single super-hot atom-sized point of existence, in an non-existent universe. Instead, it is a Universe sized atom of Bose/Einstein Condensate: Known as the Ether.

Bose/Einstein Condensate is liquid Hydrogen frozen at absolute zero Kelvin. When Hydrogen is frozen at absolute zero Kelvin, all molecules begin to vibrate in unison, and acts, reacts, and behaves as one single atom - regardless of the size of the condensate (a singularity).

The Big Bang, under the Steady State Theory, happens when an impurity in the condensate (such as an unstable element's decay) causes the Condensate to warm, melt, and outgas. This outgassing causes expansion.

If the heating and outgassing is sufficiently large enough, a Nebula, Solar Nursery, and solar system protoplanetary disk is created, forming Gas Giants, which become suns - once they reach critical mass. This causes more heating, outgassing, and expansion: resulting in more solar systems.

In the theory of stellar nucleosynthesis all other elements and matter are created in the massive gravity and superheated conditions found within the heart of these new suns. As suns die and explode, these elements are scattered across the universe.

Eventually, some suns grow so massive, that they develop a gravity so great, that light itself cannot escape. These are known as Black holes.

According to the Steady State Theory, all matter in the Universe will eventually fall into a Black Hole, and these Black Holes will collide and merge into a single, or a small number of, Black Holes in the universe. These Black Holes strip atoms down to their base elements... Tearing them down into Hydrogen again, and eventually down into a soup of electrons, neutrons, and protons: which are the only thing small enough, and moving fast enough, to escape the polar regions of the Black Holes - filling the Universe with the raw elements needed to form the Hydrogen which then cools to absolute zero again to form a Bose/Einstein Condensate Primordial Atom again.

According to the Steady State Theory, the accidental discovery of cosmic microwave background radiation in 1965, by Arno Penzias and Robert Woodrow Wilson, is not hearing the Big Bang - but rather hearing the continued outgassing of the Bose/Einstein Condensate along the outer rim of the universe, as the outgassing causes the universe to continue to expand.

It explains the extra energy causing the continuation of expansion, which the big bang theory cannot without inventing exotic matter.

It explains why the universe's temperature has reached uniformity, and such a cold temperature. By starting out at absolute zero Kelvin, the universe did not have to lower its temperature by 100's of thousands of degrees, it simply had to rise three degrees Kelvin.

It also allows for wormholes, without the need of multiple dimensions and the folding of space in upon itself (Research: "fountains in Bose/Einstein Condensates"). And opening a wormhole would only require the power from a transistor battery: Not hundreds of suns. Making interstellar space travel not only possible, but simple.

It also throws great disparaging results on red shift methods of measurements. A Bose/Einstein Condensate has the ability to slow light down to one mile an hour, without changing any elements of the light itself. So if you are measuring how far away a star is, based on the red shift of the light from the star, and that light is passing through Bose/Einstein Condensate during its journey, the light is no longer traveling at the speed of light: It may be traveling a hundred years at one mile an hour. So, the light's red shifts one hundred years, but it never traveled 100 light years to get here...

Which explains why, when our satellites look back at our own Sun from out near Neptune, our sun is barely able to be seen. If the light fades so quickly within a fraction of a single light year - why can we see any light at all from stars hundreds of light years away? Could it be they are millions of times closer than we think? Because Bose/Einstein Condensate slowed the light to one mile an hour, for hundreds of years...

And finally, under the Big Bang Theory, the Universe will end in a BIG RIP: where the suns will eventually run out of fuel, the galaxies will all go dark, the galaxies will all drift apart, and the Universe will grow cold and die.

Under the Steady State theory, the Universe will never die. The local galaxies will eventually fall into the Black Holes in the center of each Galaxy. The Black Holes will strip the Electrons, Neutrons, and Protons from all matter, and spew them out into the Universe, to be recycled back into a new Condensate.

In the meanwhile, the Universe continues to expand, creating new solar nurseries: so while one hemisphere dies off and is recycled, another hemisphere of the Universe is thriving and continually expanding. This means the Universe is in a steady state of existence.

From a religious standpoint: If light is introduced to a Bose/Einstein Condensate - it causes warming, outgassing, and the creation of the Universe... So, the Universe could have easily been created by the simple introduction of "Let there be light."

Cosmic microwave background radiation.

There are several aspects of the Big Bang Theory supported by observed phenomena:

• The current universe is presumed to have a beginning state.
• Some galaxies appear to be moving away from us at speeds proportional to their distance. This is called "Hubble's Law," named after Edwin Hubble (1889-1953) who discovered this phenomenon in 1929. This observation supports the expansion of the universe and suggests that the universe was once compacted.
• The initial, very hot state that followed the Big Bang should have left some remnant of its heat. In 1965, Radioastronomers Arno Penzias and Robert Wilson discovered a 2.725 degree Kelvin (-454.765 degree Fahrenheit, -270.425 degree Celsius) Cosmic Microwave Background radiation (CMB) which pervades the observable universe. This is thought to be the remnant which scientists were looking for. Penzias and Wilson shared in the 1978 Nobel Prize for Physics for their discovery.
• The abundance of the "light elements" hydrogen and helium found in the observable universe (which would have been the first elements formed) is thought to support the Big Bang model of origins.

The idea is that, since galaxies are moving away from each other now, then they used to be closer to each other. Extrapolating backwards in time, one can go back far enough to a time and place where all matter resided in a very small, dense region. called a singularity.

This state would have been all energy, as matter could not have existed as we know it in an energy field so intense. The "Big Bang" was the release of that energy, creating the current era of spacetime.

The energy dispersed and, as things cooled down, matter began to form. It's the expanding universe that is the evidence for the Big Bang.

Replacing The Steady State Theory

The Steady State Theory was an early, only partly scientific proposition put forth to explain how the universe around us created matter on a continual basis. Founded in large part on the ancient idea that our universe was a firmament, and only subject to margional changes, like those caused by us, the explosion of a star, or the effects of gravity as it pulls back the matter and energy from those stars and creates new objects, the Steady State Theory basically told us that the universe was always here and always would be...and also would remain the same size.

The later advancement of science in new areas such as quantum theory, relativity, and Edwin Hubble's discovery that the universe was actually expanding, all pointed in a direction different from that of the Steady State Theory. This led astronomers and cosmologists to begin pondering what the universe would have looked like before its expansion. At some point in the past the universe must have been much smaller, but how much smaller could it have been?

Quantum mechanics allows us to imagine and make practical predictions about how tiny the universe could have been in the past, which greatly helped the Big Bang Theory to catch on. It was suggested that the universe was at one point so tiny that it was the size of the tip of a needle, and was referred to as a singularity, much like the singularity of a black hole. But a black hole limitlessly pulls in everything around it, and there's no evidence of black holes exploding and creating new universes within our own. So the singularity idea faded away, though almost painfully slowly in some circles.

Journalists, and sometimes scientists, will erronously state that there was once nothing, and then the Big Bang created the universe. This isn't correct. There was never "nothing." You can look at this in two ways. 1) Energy can be created from matter, and matter can be created from energy. In fact, matter pushed to the speed of light literally becomes energy. Thus, even if the universe were crushed under all it's own gravity at the speed of light into energy 13.7 or so billion years ago at the place where the big bang occured, there was still energy. There was still something. Then there's option 2) Maybe God created the uinverse, but He would still have been here before us so there could never have been nothing.

With option 1, the universe began as energy packed so tight that even our theories of quantum mechanics cannot agree on what might have happened. It seems logical, at least on our common macroscopic level, that energy packed so tight would explode and begin expanding outward. And if we started from energy, that energy had to come from somewhere. Perhaps from some prior universe.

The Big Bang Theory is the prevailing cosmological model that explains the early development of our Universe. Basically, it states that at one point the Universe existed in an extremely hot and dense state known as a singularity, which was composed entirely of energy. Then, around 13.7 billion years ago, this tiny singularity expanded very rapidly in an event known as cosmic inflation. As the Universe expanded, it cooled and became less dense. Energy was converted into subatomic particles, which would later come together to form atoms. The first elements were hydrogen and helium; heavier elements would be synthesized within stars or during supernovae. The Big Bang is considered to be the origin of space and time, and everything in the Universe was formed from the energy released by it.

The Big Bang Theory does not fully explain the true origin of the Universe, it is only based on the fact that a singularity (which was the Universe) was already there and that it expanded to form the modern Universe. What caused the singularity to expand, how it came into being, and what was before it is unknown. Speculation abounds, but ultimately the cause of the Big Bang may never be fully realized because this is outside our realm of observation.

The idea that would become the Big Bang Theory was first proposed by a Catholic priest named Georges Lemaitre, who called it his "hypothesis of the primeval atom." Since then, scientists have built on his ideas and much evidence has arisen. The Big Bang is a very well tested and widely accepted model and is the best explanation for the full range of phenomena astronomers observe. Since its conception, many scientists have proposed alternative theories, but none of them could hold as much weight. The two most commonly mentioned pieces of evidence for the Big Bang are the expansion of the Universe and the cosmic microwave background, although much more exists.

It has been consistently observed that galaxy clusters are moving away from each other and the universe is expanding. Expansion is observed through a phenomenon called redshift, in which the lightwaves from objects that are moving further away are stretched towards the red side of the spectrum. Almost all the galaxies outside our Local Group are moving away from us in every direction. If the Universe is expanding, it must have been smaller in the past. The Big Bang Theory makes more sense when we know this.

Furthermore, the discovery of the cosmic microwave background radiation in the 1960's helped validate the Big Bang. This leftover thermal radiation permeates the Universe almost uniformly, and is from an early stage in its development. When the Universe was still young, it was very hot and filled with an opaque fog of hydrogen plasma. As it expanded and cooled, stable atoms could form. These atoms could no longer hold onto the radiation, and it was released into space, making the Universe transparent. That same radiation which was released long ago remains today as a weak afterglow of the Big Bang, and a confirmation of the event.

Misconceptions

There are some widely held misconceptions about the Big Bang. This is due to the difficulty in clearly and accurately defining what the event was and what the theory actually says to the general, nonscientific population.

1. The Big Bang does not explain the true origin of the Universe. Its primary focus is the development of the Universe over time.

2. It was not an explosion of matter into existing space. Rather, it was the expansion of space itself. Picture an inflating balloon, or a crumpled map being unfolded.

3. It doesn't say that "something" was produced from "nothing."

4. The fact that we do not know for certain what caused the Big Bang is not a weakness in the theory; we know it happened regardless of what caused it

Please see the links below for more information

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It's also:

• A US TV sitcom
• An album by Styx
• An album by Harem Scarem
• An episode of Family Guy.

God created Earth and Heaven

There are thousands of creation-narratives and the Christian version is one. The Big Bang is the scientific answer to the creation of the universe but it still has its faults. The electromagnetic activity and "expansion" of universe indicates there had to be a vast explosion, one that humans can not comprehend because the greatest explosion we have seen is that of a nuclear bomb which is not comparable to the scale of what the Big Bang would have been. The truth is that no one knows but this doesn't mean that we never will and science is at the forefront of finding answers. Creation stories focus on our immediate solar system and galaxy and of course the universe contains millions of galaxies comparable to ours and may contain life similar to earth's. The Christian creation-narrative stipulates that the sun was created after the earth and this is certainly not the case.

"Big Bang" Answers

* "God has stated that He created the universe and all there is in it. Man, rather than believe God's word, has entertained various theories." A reader will look very hard indeed to find a more deceptive statement. It leads the reader to believe that by theorizing the mechanism of creation we deny or reject God. That is a patent falsehood. If God created the universe, how did He do it? He didn't bother to elaborate. We'd like to know. So we try to find out using various means. Science among them. The question is posed as if, when looking at the two choices, an individual contemplating the origin of the universe has to pick God or Big Bang. There are other possibilities. Perhaps these two are put up because they are arguably the most "popular" and are better known. Oh, and who said the creation of the universe by God or by Big Bang are mutually exclusive? Could not God have used "natural" means to create the universe by the mechanism of the Big Bang? There is no shredof physical evidence that will contradict that idea. None whatsoever. Consider the controversy over the behavior of light. It behaves like a particle in some experiments, and behaves like a wave in others. Both sides had bulletproof (scientific) evidence. The scientific community drew battle lines. It got ugly. But cooler heads prevailed. Now we know that light exhibits what is called wave-particle duality wherein it exhibits properties of both. It's not a particle or a wave, but rather a "wavicle" in the jargon of some investigators. The same thinking could apply here. At the risk of being repetitious, let's review. Did God create the universe? There isn't one piece of physical evidence to support that idea. Is Big Bang theory confirmed by scientific fact? No. It's merely suggested. (It's a theory.) Could God have created the universe via the Big Bang? That's another theory. And no evidence whatsoever can be shown to refute it. Welcome to the Custom Burger Barn where you can have it your way. What would you like, please?

"God" Answers

* I suppose the answer depends upon in whom you place your trust. Those who believe in God believe that He created the universe and all there is in it. Some further believe that Man, rather than believe God's word, has entertained various theories, none of which have been substantiated to the satisfaction of the Creationist movement.

* All indications would seem to suggest that God may well have used a 'big bang' of sorts to create the universe based on the premise that it all had to have started first from a 'thought' or an 'idea' that could then be put into motion.

* "What has been will be again, what has been done will be done again; there is nothing new under the sun." Ecclesiastes 1:9

We are not the first forms of life on this planet and under this sun and we will certainly not be the last. Forget what Apostle Paul tells you, the entire universe was not created just for our pleasure, and when we no longer exist it will keep going for much much longer.

* The answer is that God created the universe and there was no other god before God because God already existed always.

* The primary source for the Judeo-Christian belief regarding God creating the universe in a deliberate and systematic series of steps is in the Book of Genesis.

"Other" answers

* It is possible that God created the universe by way of the Big Bang. There is currently no physical way to prove this to be true or not. There is no doubt that the universe is expanding, and if the "film" was "rewound" to the "beginning" of things, then a "Big Bang" is a most probable logical start. Recall that science is not out to prove God does not exist. It proves what it can, and illuminates other things, like an expanding universe and a possible explanation for how it got to be the way it appears now.

* God did not create the universe, the universe was created by means of the big bang and that is final no questions. God does exist no doubt but he did not create the universe, a small ball of plasma kick - started the universe. Just think what the world would be like without gods to worship, it would be chaotic.

* Yes and no. the human mind is a powerful thing. And some believe our universe is made up of many dimensions and planes of existence. If you follow the path of The Christian faith, Then God created the universe. Some would say something created God, and something created that, and so on and so on. Or, you could just believe that the Big Bang did it. In this belief, with all of the multiple planes of existence, every thing is true, and at the same time false.

Scientists tell us that 4 components are required to have a universe. Time, energy, space and matter.

Genesis 1:1 - "In the beginning (time) God created (energy) the heavens (space) and the earth (matter)."

Physics is the study of matter, energy and the interactions of the two.

Physics can be divided into two main branches: mechanics (the study of the behavior of forces and objects acting due to those forces); and, electricity and magnetism (which delves into the science of the atom).

The fundamental branches of physics:

classical mechanics

electromagnetism (including optics)

relativity

thermodynamics

quantum mechanics

astronomy

electromagnetism

Some of the more popular or modern branches of physics:

Astro and space physics (study of stars, planets, black holes, etc.)

geophysics (study of like earthquakes and plate tectonics)

nuclear physics

particle physics

medical physics

biophysics, and quantum physics, which is mostly theoretical
identify the different divisions of physics

Not since the Big Bang.

Your question seems to suggest that you accept the idea of a Big Bang, since you use the term 'Big Bang' as a reference to time.

The concept of infinity also is used in reference to time. unending time.

Time as we perceive it began at the instant of the Big Bang. Along with space. The space we see out there that we call the universe, with all the energy and matter contained in it, which seems to be fated to expanding ever faster with time. Time as we know it.

We think of time as time forward or time back. We seem to think of infinity as time forward. Knowing what we believe to be true of the universe, today, during our time, makes it difficult to think of an infinite time in the past because of our concept of the Big Bang. It is an indelible reference point in our mind when we try to conceive of the universe and its beginning, in time. Time back. But to a point. Not infinitely back. An infinite future time is not so difficult to imagine.

If this time is the only one we can perceive, and we can see that at this time ( a manifestation of space-time), there is all this expanding space with all its energy and mass (again, two manifestations of the same thing), then we must accept the notion that there is something, not nothing. At least since the Big Bang.

The instant of the Big Bang, the beginning of time and space, ended the possibility of an "infinity of nothing". All of a sudden, there is something.

In any discussion of infinity-eternity-everything-nothing one should research the concepts of "dimensionality and branes". Try looking up M-theory.

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It does, or it can, suggest an infinity past. It is no less reasonable to theorize a past infinity as it is to theorize a future infinity. We convince ourselves that a future infinity is meaningful while a past infinity is not, but this comes more from the limitations of our minds than anything else. Either way you are talking about an infinitely long stretch of time, with one terminus in time.

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True. Any further discussion must surely include the possibility that our universe was born in the 'Big Bang' event, and that the 'Big Bang' itself occurred when two 'branes' collided in a larger 'multiverse' of eleven dimensions. But if you go into that particular discussion, you must discuss gravity and it's strength relative to the other known physical forces, and perhaps the idea that gravity is a force acting within and throughout the 'multiverse' and distributed in some way between all the universes that exist within said 'multiverse. The other thing we don't wanna' discuss here then is the concept of 'time' as it relates to the 'multiverse'. Makes me shudder.

Jesuit priest Georges LeMaitre was the first scientist to show that an expanding Universe with a specific begining date was consistent with general relativity.

Einstein initially ridiculed LeMaitre by saying, "Your math is correct, but your physics is abominable." Einstein later admitted that his rejection of LeMaitre was his biggest blunder (he credited several things as 'his biggest blunder').

Sir Fred Hoyle coined the term "Big Bang Theory," although Sir Fred did not fully support the idea.

A man named Georges Lamaitre. A catholic who was shot down by science for this theory of the big bang in 1927

The Big Bang Theory was first postulated by the Father Georges Henri Joseph Édouard Lemaître, a Catholic priest from Belgium; he was a physicist and astronomer.


Georges Lemaître, a Belgian physicist and Roman Catholic priest, who, in 1927, independently used Friedmann's equations to propose that the inferred recession of the spiral nebulae (per Edwin Hubble's discovery of 1924) was due to the expansion of the Universe, is considered the father of the Big Bang Theory. As such, the Jesuit priest Georges LeMaitre was credited with being the first to mathematically detail a cosmological study now known as the Big Bang.

However the consensus for modeling cosmology was agreed upon based on the work of four scientists: Alexander Friedmann, Georges Lemaître, Howard Percy Robertson, and Arthur Geoffrey Walker. Occasionally referred to as the FLRW, FRW, FL, or RW (e.g., a complete or partial combination of their last initials) Universe, it presents a metric used to explain Einstein's field equation of general relativity and thus became the foundation for the currently understood version of the standard 'Big Bang Theory'.

Note: While the Friedmann Theory preceded the Big Bang Theory, the developed equations were fundamental to establishing a foundation for the Big Bang Theory. Alexander Alexandrovich Friedmann is best known for his pioneering theory that the universe was expanding, governed by a set of equations he developed from Albert Einstein's equations of general relativity, showing that the Universe might be expanding in contrast to the static Universe model advocated by Einstein at that time. From these equations he postulated three Friedmann models describing positive, zero and negative curvature respectively. This dynamic cosmological model of general relativity would come to form the standard for both the Big Bang and Steady State theories.

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The name "Big Bang" was coined by Sir Fred Hoyle, who was a life-long proponent of the alternative "steady-state" theory of the universe. He used the phrase "big bang" in a sarcastic way.

The cause of the Big Bang is largely speculative and is one of the most difficult questions to answer. It is a complicated and perplexing issue that is a topic of some serious research by scientists. We will probably never find concrete evidence for what caused it because this is outside our realm of observation. The Big Bang describes some of the earliest moments in the Universe's existence, but it cannot go back to time zero.

For many, "God caused the Big Bang" is a perfectly reasonable response and helps them cope with the unsatisfying prospect of an event without a cause. However, one is then forced to ask "From where did the creator come?" If the answer is "he always existed" then we have a situation, from a causality standpoint, that is no more satisfying than a universe that springs forth from nothing. A creator that has always existed is an entity that somehow exists without a cause.

Another hypothesis is that the Universe is cyclical and that it goes through an infinite number of "Big Bangs" and "Big Crunches". However, the Big Crunch has been determined to be unlikely due to the discovery that the Universe is actually expanding faster. Not only that, an infinitely cyclical Universe has other problems having to do with entropy and thermodynamics.

One of the most popular current theories is that the Universe is one of an infinite number of Universes collectively known as the multiverse. According to this, universes have always existed, popping in and out of existence like bubbles. Scientists are currently searching for possible evidence of the multiverse. One suggestion proposed by M-theory is that the collision of "membranes" existing in higher dimensions causes Universes to come into existence. Another associated theory is string theory.

For the serious investigator, there are a group of highly complex theories that can possibly explain the Big Bang. The origin of the singularity that appeared in the first instant of the Big Bang is uncertain. Though our understanding of natural laws expands all the time, we still don't have the tools to pin down the answer to this question, and it is likely that we may never know for certain.

If you want to learn more about this contentious topic, follow the links below regarding various theories.

At the moment there is no definitive answer to this question, though various theories do try to address the question.

One idea is that it is merely a consequence of quantum mechanics and the uncertainty principle..basically it's the highly unlikely, though possible, spontaneous creation of particles.

Given that time did not really exist before the big bang, it doesn't really matter how long such a thing would take.

Another idea in string theory is that two universes, composed of 'branes' collided, and spawned ours in the reaction.

We may never know the answer to that question. We know what happened a fraction of a second after the Big Bang, but we don't know what happened at or before that point, because that is the origin of space and time.

We can only speculate, because whatever caused the Big Bang lies outside space and time, and if it lies outside space and time, it is impossible to observe.

Some hypotheses include a multiverse, quantum fluctuation, and even a supernatural being.

No one even knows for sure if there was a big bang, let alone what caused it. The big bang is a hypothesis based on extrapolation of alleged outward motion of galaxies back in time from the earth as center of the Universe, which motion is based on the assumption that the cosmological red shift is caused by a Doppler red shift of the light. Unfortunately for that hypothesis there is no other additional evidence of that Doppler shift or that motion. To see an alternate explanation of the loss of energy by light as it passes through the Universe

ADDITION:

Because we can only view our universe from Earth (which, by the way, is not the centre of the universe), we could also be viewing what we 'perceive' to be an expanding universe (Red Shift) only because we are withdrawing (being pulled away from) from the rest of that universe - along with the local group within our galaxy (Large Cloud of Magellan, Small cloud of Magellan, M32, NGC147, Andromeda, Ursa Minor and the rest . . . all of which are not redshifted and rapidly moving away from us, and in fact from our perspective from Earth, Andromeda is rapidly moving towards us). This would imply that a super massive Black Hole is effecting all of these local bodies (including our own solar system).

If we had the faintest clue what time was we could have a slightly educated guess!! But as time is slowed by gravity, (relativity) and if all the mass in the universe was at one quantum point before the big bang, there would be far too much gravity for time to exist. in theory of course it doesn't even exist in a common or garden black hole, as it's directly related to the speed of light, and light has 0 speed in a black hole.

As these answers show, nobody really knows anything about it. My theory is that the universe goes in infinite cycles of big bang, to big crunch, to big bang, you couldn't get more simple. Gravity sucks the black holes back into one supermassive black hole, which cannot support itself, and the collapsed atom splits and creates another big bang. That is the most logical, and rational explanation.

It explains why the big bang happened, and it does not contain any crazy ideas. What goes up must come down, energy equals mass multiplied by the speed of light squared, and mass equals energy divided by the speed of light squared.

Roughly 3K, close to the temperature of liquid hydrogen. It was billions of K when it first escaped following the Big Bang roughly 13 billion years ago, but the universe expanded and cooledas well as Doppler red shifted it until it looks very cold now.

About 2.725 Kelvin.