| Chairman-Mao said: I'm conservative too so I don't mind seeing this. I'm sick of all this talk of keeping religion out of schools but its okay to teach theories (big bang theory) as if they are fact. |
I'm afraid that you are unaware of what a scientific theory is, no problem everyone needs someone to tell them at some point. It's not like a theory you use in everyday speech, a scientific theory is a group of facts used to explain a feature of the natural world. In other words, when you see the word theory in science it means there is such an abundant amount of data that indicates scientists really are 99% certain that it is the truth (it can never be 100% by definition).
Let's take a look at the example you provided, the big bang theory. Now when I first came across this in school I thought it sounded far fetched, however a few years ago I got to reading about it and it's not just that scientists think it happened, it's more of a case that there is so much evidence that it must have happened.
I'll have a go at explaining the big bang, the evidence we have and how we got to the conclusions we did based on the facts. This is how a theory is formed.
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In the early 20th century a man called Edwin Hubble had discovered that galaxies existed beyond our Milky way, which we thought was the only one. The discovery was astounding, but what came next was even more so. Hubble devised a way of measuring the location of these galaxies called "redshift", he carefully and painstakingly measured the location of many galaxies and tracked their movement.
What he found was that they were all moving away from each other, and none moving towards another one. How can this be? The only way to explain it is that it's not the galaxies that are moving but the actual space they exist in is expanding. Imagine it like a balloon with dots on being blown up, they were close when the balloon was deflated, but now the balloon is blown up the dots are further away from each other. The location of the dots on the balloon haven't changed, the balloon itself has expanded making them further away.
Fact #1: What this shows is that the Universe is expanding. It has been observed for decades now and measured many many times.
Now, onto the next bit of information. We can observe two things in the Universe, Galactic evolution and the abundance of Hydrogen, which shows the Universe is finite, it has not existed forever. In fact best estimates suggest it is 13.7Bn years old (although I believe it is slightly older still). How do we know this?
The first matter that formed was Hydrogen, all original matter was Hydrogen, one proton, one neutron and one electron. But when stars formed they began fusing this matter in a process which is called nuclear fusion, a process man can even replicate on Earth. This is where atoms fuse together to produce new atoms like Helium, Oxygen, Carbon, etc... This is where all other matter comes from. We know with the amount of Hydrogen we can measure in the known Universe that the Universe must have had a starting point.
Fact2a: Universe had to have a starting point, a moment where it began.
Now, when astronomers look into the night sky they notice something odd, the further they look back, the less evolved galaxies look (Because light takes so long to get here galaxies that are 10Bn lightyears away only just reach us, so we see them as they were 10Bn years ago). If galaxies are less evolved than ours then we must assume that at some point back the Universe began as it is clear that stars and Galaxies have not existed forever. What we can take from this is that the Universe must have had a starting point and that we can actually see through telescopes back to almost when that starting point began by observing galaxies.
Fact 2B: The Universe if finite. This is the same fact as before, but reinforces it to an undeniable level.
Now let's try and make a conclusion the same way scientists do. We know two facts, the Universe is expanding in a metric way and the Universe has existed for a finite period of time. These are two undeniable facts. What conclusion can we draw form those two facts?
If the Universe is expanding and has only existed for a finite period of time then logically it must have had a point where it began, where it was a singularity and started expanding. It is the only explanation. This is what is called the big bang.
From these facts we can explain a force of nature (the big bang). We call this a theory because it is a collection of facts, which is what a scientific theory is.
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Personal note: Don't think of the big bang like an explosion. If I can go back to the balloon, think of it like that. The balloon was once deflated (a singularity) and then it was blown up (expansion). We know it happened over a period of time and we know it is expanding, just like the big bang theory.
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Phew, I hope you stuck with me with the wall of text.
