Do we know that the big bang is a fact, or is it just an idea that explains why the universe is expanding from what appears to be the center?
Could what we call the universe be nothing more than a molicule which is receiving more energy than it is releasing, and thus expanding according to Boiles Law (which is a fact)?
No Latin please, I know what uni means. It isn’t my fault that Daniel Webster didn’t realise we would need another word.
If the big bang is a fact I will go from there. I’m not schooled so try to talk at my level, and please don’t give me an explanation which you don’t really understand, but have accepted merely because you heared it from someone more intellegent than yourself.
No theory can be proven 100%. We are unable to see the actual Big Bang, so all we can do is observe and extrapolate. That is what a theory is: the best explanation based on observations and backed by evidence.
And the Big Bang has a lot of evidence behind it. Cosmic Microwave Background Radiation is one key piece of evidence that was predicted, and subsequently observed. That is the strength of a correct theory, its ability to predict.
However, if new evidence is uncovered that suggests the Big Bang could not have happened, then the theory will have to be revised or discarded and a new one will have to be developed.
Big Bang Theory Facts
Like all scientific theories, the Big Bang can never be proven as a fact. All we can do is find evidence that either supports that theory or refutes it. So far, we have not found evidence that refutes the theory. Therefore it is a good scientific theory.
The universe is expanding. This has been confirmed so many times now that there’s no real point in arguing against it! We know this by looking at the light from distant objects which show a red-shift in the spectrum consistent with objects moving away from us. Now, the starting point of the Big Bang theory was basic logic:
if the universe is expanding, then that means it was smaller in the past
at some point in the past, the universe must have been so small it could be considered a single point
Now, if you start with that assumption, then you can begin to make predictions about the conditions of the Big Bang such as the temperatures and energies that must have been involved. And then you can make predictions about how particles were formed from the energy, how forces such as gravity and electromagnetism arose, etc.
The reason the Big Bang theory is so widely accepted is because we can reproduce the energies that existed a few moments after it started. We do this in particle accelerators, like the ones in CERN. In other words, we can use astronomical observations and theoretical physics to predict the conditions shortly after the Big Bang. When we replicate those conditions in particle accelerators, we can see how different particles were formed, we can see things like the Higgs Boson which gave particles mass, we can see how the forces of nature split apart, etc.
So we have particle accelerators at high energies giving rise to the particles we see in the universe around us, and we have observations confirming that the universe was smaller, denser and hotter in the past which replicate those conditions!
It has been 50 years since two scientists found landmark
evidence for the Big Bang theory. Here are some little-
known facts about the Big Bang theory and its champions.
Robert Wilson and Arno Penzias were using a large horn
antenna at Bell Labs in New Jersey to gaze into the Milky
Way. What they found, however, let them peer back
378,000 years after the Big Bang. The two scientists
eventually found a cosmic fog that permeates the universe
in every direction. Called the cosmic microwave
background, it is a signature of the Big Bang that formed
just after the universe began 13.8 billion years ago. [ The
Universe: From the Big Bang to Now in 10 Easy Steps ]
But understanding what they found in 1964 was no easy
task. Here are five odd facts you probably didn’t know
about the Big Bang theory and those who discovered it.
Big bang theory is a theory, which means that it is a set of ideas based on facts and linked by mathematics, not some airy-fairy junk dreamed up as a joke over a few beers.
No, the Universe is not a molecule or an atom, because the relative scales of atoms, molecules, solar systems, galaxies, and clusters of galaxies are considerably different. Apart from that, the physics of atoms, electrons etc are different from that of large objects. Don’t worry, nearly everyone who thinks about it has that idea at some time.
Here’s the history of the big bang theory, a very short version. it does not cover everything. Since the basic theory was proposed in 1931 just about all the objections have been considered.
Pass light through a slit, then through a prism or preferably use a diffraction grating and the light spits up into a rainbow – like spectrum. Because all atoms and molecules emit light of a particular colour when going from an excited state to a ground or less excited state, these colours turn up as stronger lines which are images of the slit. Darker lines can also show that some of the light has been absorbed. These things are not theories, but observed facts, first noticed in the 1800s.
The positions of these lines, in comparison to the positions of the same lines obtained on Earth is a indication of whether the object being viewed is moving toward us when the shift is to the blue or shorter wavelength or away from us when the shift is to the red, the longer wavelength. The amount of the shift is a measure of the relative velocities of the source of the light and the observer. This is called the “Doppler effect” and has been known since the 1800s. it is obvious with sounds and is not a theory, but an observed fact.
This red shift was noticed by Vesto Slipher at the Lowell Observatory before 1920, then in the 1920s Edwin Hubble and Milton Humason working near Los Angeles began to measure it as well. So by 1931 there were a few dozen measurements, and now with more sensitive and automated instruments there are millions taken by almost every large telescope in the world. Not theories, but observed and measured facts.
Where theory comes in is from the general theory of relativity developed by Einstein where his equations provide for an expansion or contraction of the Universe, Einstein thought the Universe was static and inserted a term called the cosmological constant to make the equations show a static universe. He called that his biggest blunder later on. In 1919 it was found that Einstein’s equations were correct with observations by Arthur Eddington, and the same thing has been done many times since, The equations are an essential part of the GPS system. That theory is now routine commercially used technology, so it’s not “only a theory”.
In 1931 Monsieur Georges Lemaitre, a physicist and Roman Catholic priest in Belgium combined the observations by Hubble and the equations of Einstein and predicted that all the matter in the Universe was at one time in the same place, where it existed as energy. This was thought of at the time as a good idea, but it didn’t go much further than that. It was called the “cosmic egg” or “primeval atom”. In 1949, the British physicist Fred Hoyle who didn’t like Lemaitre’s ideas called it the “big bang” as a joke on a BBC radio broadcast and the name stuck.
Later, some physicists worked out that if Lemaitre was correct, the Universe should be filled with radiation in the microwave region of the radio spectrum. Various estimates were made and by 1963 it was calculated that the peak frequency should be in the lower end of the 3,000 megahertz to 30,000 megahertz band.
That was accidentally discovered by Penzias and Wilson at Bell Laboratories in 1964, at a peak of 4080 megahertz. They were actually trying to set up for communications satellites. That has been confirmed so often since that it is also routine. So Lemaitre was right. Because the big bang theory has solid, measured evidence to back it up, it is a proper theory.
Most of these theories are merely just that: Theories. The Big Bang is a theory that can’t (as of yet) be proven. What seems to be the center of the universe from where the initial ‘big bang’ occurred can not really be proven to be the center. The reason why they think it is however, is because as we go back into time using the formula (not exactly sure which) we eventually can’t go further without using the infinity symbol. And real arithmetic can’t be done with the infinity concept because it is so abstract (space time and using infinity in the formula). My point is this: Where we think the center of the universe is (and also where the supposed big bang originated) can not be proven or said without a doubt because we can’t go further back in time using the infinity symbol (yet ;-)). Not much of space can really be stated for certain. For now, my friend, it’s just philosophical.
There is a theory about how the expansion of space affects the energy content of the universe:
Same amount of energy + more space to spread it out = the energy DENSITY goes down with time.
It was given the awful nickname “Big Bang” in 1949 (one year after the theory was published) by an adversary of the theory (Fred Hoyle).
The theory itself came from a mathematical model (and idea) of a catholic priest: the model is from around 1930; the Primordial Atom Hypothesis is from 1927 (the hypothesis and the mathematical model are both from Father Lemaitre).
As a theory, it tries to show how some basic physics concepts can explain the behavior of the universe over the last 13.8 billion years.
The theory itself is NOT about the beginning of the universe. The theory simply accepts that energy exists in the universe (the theory does not try to explain why) and that space is expanding (based on observations from the late 1910s and early 1920s — by the American astronomer Ewin Hubble and the Belgian priest Georges Lemaitre).
It is possible to write a theory about how water goes from liquid to solid when its temperature goes below 0 C — without having to explain where the water came from. If you accept the observed fact that water does exist, then you could find the theory – about how it becomes solid as ice – useful.
Similarly, the Big Bang theory explains what happens to the energy density of the universe as space expands — and what happens when the density crosses critical values (for example, how some of the energy becomes matter).
As such, the theory is very useful in understanding the last 13.8 billion years of the behavior of the Observable Universe. It is absolutely useless if you try to use it “before” that inverval.
Just like a theory about how liquid water becomes ice, would be useless in explaining how water came to exist in the universe.
The earliest moment covered by the Big Bang theory is called the Planck Time (because it was first calculated by Max Planck, good friend of Albert Einstein).
At the Planck Time:
— the initial energy already existed (the theory does not explain where it came from);
— space was already expanding (the theory simply accepts that space expands);
— the density was NOT infinite (no “singularity” in the real Big Bang theory);
— matter did not yet exist (the theory DOES explain how matter forms from the energy).
It is a theory because it is only a model of how we think the universe behaves. There are still annoyances with it. For example, recent observations show that the rate of expansion now seems to be accelerating (which is something NOT predicted by the theory).
For now, the Big Bang theory is still the best model we have to understand the “recent” behavior of the universe (the last 13.8 billion years).
There is NO initial explosion in the real Big Bang theory (there was an explosion in the hypothesis of 1927, but that was NOT kept for the theory). There is no “infinite density” in the theory (there was in the hypothesis).
The adversary (Fred Hoyle) who gave the awful nickname “Big Bang” was well aware that people still remembered these things, so that his awful nickname perpetuates the false idea that the Big Bang theory describes an explosion.
It does not.
It is a Theory, facts about the beginning of our Universe are hard to come by.
All we can make of theories is look at the facts that are there and maybe make guesses assumptions and try and look at the ancient past by turning the clock back.
What happen before the Big Bang has been a free for all for guesses.
The only sure fact is that we are here.
The “Big Bang” is a model that predicts certain large-scale features of the universe. In scientific terms, that’s the definition of the word “theory”. In common speech, the word “theory” means something else, more like “guess”. But that’s not what scientists mean when they use the word.
More precisely, “Big Bang” is the name used for several models of the universe, with slight differences between them. The most accepted version is the “Lambda – Cold Dark Matter” model, but even that comes in various flavors.
It’s not a “fact” because it’s not a direct observation. It’s a model that makes very good predictions, better than any other model. By adding various details to the model, we can make it match more and more observations. So far, it seems that plugging in just six numbers (or a dozen in some variations) is enough.
The reason the Big Bang theory is so widely accepted is because we can reproduce the energies that existed a few moments after it started. We do this in particle accelerators, like the ones in CERN. In other words, we can use astronomical observations and theoretical physics to predict the conditions shortly after the Big Bang. When we replicate those conditions in particle accelerators, we can see how different particles were formed, we can see things like the Higgs Boson which gave particles mass, we can see how the forces of nature split apart, etc. It’s not a “fact” because it’s not a direct observation. It’s a model that makes very good predictions,