He said that the big bang was the start of our Universe, which I think you'll find all the evidence points towards. I'll risk repeating myself, so I'll just keep this short and if you need anymore information either look back at earlier posts about the big bang or research it yourself by reading scientifically valid peer reviewed work.

We know two facts, the Universe is expanding and it has existed for a finite amount of time.

How do we know the Universe is expanding? Because a man named Edwin Hubble made a series of painstaking calculations of the movement of galaxies over the course of a decade, determining the data by calculating the shift in apparent electromagnetic frequency as would be predicted by the Doppler effect. If it shifts towards the red end of the spectrum, the galaxy is moving away, and if it is blue it is moving towards us.

Lo and behold, every observed galaxy is in redshift. In other words they are all moving away from us and each other. Hubble's observations can only lead to one conlusion, the universe is expanding. Look at my earlier analogy of the dotted balloon.

This is called hubble's law, and it is a solid fact (you said you wanted facts).

We also know that the Universe has existed for a finite amount of time.

The first fact supporting this is the observed evolution of galaxies. As light reaches us from distant galaxies (so we see them as they were billions of years ago) we can see that there is a progression in the form of their structure.  This leads us to conclude that galaxies could only have existed for a finite amount of time, and we can track their evolution from primitive galaxies to modern galaxies.

The second fact is the abundance of hydrogen. If the Universe has existed for an infinite amount of time the vast majority of hydrogen would have have been used up in the fusion of atoms in stars. Yet the fact remains, hydrogen is extremely abundant.

Given these two facts (expanding universe, finite time frame) we have to conclude that our Universe was at one point a singularity. And if you rewind the expansion model over the finite period of time you will see that our Universe had to of begun as a singularity.

I'm not going to pretend I know what happened before the big bang, or what caused it; but I can tell you that the facts show that our Universe started as a singularity and expanded from there, otherwise known as the big bang.

And you also need to look up the definition of scientific theory before you try to challenge one. It is not the same as the common use of the word theory. A scientific theory is the explanation of a series of facts based on evidence.

In other words, a theory is evidence and facts, and not "guesswork" as most creationists seem to think.

I read your articles. Surprised? I like to learn about these sort of things I'm actually very interested in astrology. Look, yes I see where you're coming from. There could be strong evidence for the theory. I learned from my biology teacher that a scientific theory is one that "stands the test of time" and is accepted as "truth" see how I put truth in quotes. What I'm trying to say is, we don't have time machines, so its not as if we can just go back in time and confirm anything can we?

Wow... and to think you're only 20. I wish I had your discipline and determination. I might get more things done.

I know what a scientific theory is. Actually it is not an explanation of a series of facts. It theorizes based on observations and concepts. Then After it stands the "test of time" it becomes generally accepted.

In the sciences, a scientific theory (also called an empirical theory) comprises a collection of concepts, including abstractions of observable phenomena expressed as quantifiable properties, together with rules (called scientific laws) that express relationships between observations of such concepts. A scientific theory is constructed to conform to available empirical data about such observations, and is put forth as aprinciple or body of principles for explaining a class of phenomena.

Well that wont help you very much when debating astronomy, will it.

(*hehe* I kid, Kid, I know what you meant really.)

Actually I'm 21 about to turn 22, but this site is broken and thinks that 2010-1988=20

To the other post, no I'm not surprised that you read the articles.  Frankly I'm more surprised when I'm attmepting to debate when someone and they willfully ignore anything presented to them that contradicts their stance.  And what you said about being accepted as truth with quotations, well that's the way you should look at the issue.  If you think something is not correct you should set out to prove it's not, skepticism is at the very core of science and we would be nowhere if people didn't doubt what was already established as fact. 

oh, my bad, yes I actually meant astronomy

You should look up the book The Universe:From flat earth to quasar by Isaac Asimov.  It's a great read and will give you a lot of insight into the world of astronomy.  Another good book (although less dense and more easily accesible to the average reader) is Cosmos by Carl Sagan, he also did a TV series that accompanies the book (it has different information) which I have yet to watch but I'm sure it's good, 13 episodes each an hour long, 13 hours of astronomy told by Carl Sagan?  I can't imagine it not being good.

Thanks for the info, especially the tv show one. I watch history science channel with my friend and we usually get  into debates. (I would rather watch Bill Nye the science guy though he makes it interesting and fun.) 

I'm sorry, but you more or less said that I'm wrong, then cited a definition of scientific theory which states "A scientific theory is constructed to conform to available empirical data about such observations, and is put forth as a principle or body of principles for explaining a class of phenomena", which is pretty much what I said.

Besides, I'm fully aware that a theory has to conform to the evidence when theories are challenged (because how would they become more correct otherwise?). And I think that goes without saying when I say the explanation is based on the evidence. When new evidence is introduced, the explanation has to change. I think I've repeated myself enough in the past on the definition of a theory though.

Either way it is an ad hominem attack. You decide to try and attack my credibility at the end when I corrected you; instead of offering a rebuttal to the facts that I gave you, which is what you were interested in in the first place.