I have to ask, where is the evidence for your statement that God made the heaven and the earth? By that I mean your belief. Although I am an atheist I am trying to understand how people can keep their belief when there is no evidence to underpin that belief. – Fergal Keating (In response to this Quora answer)
What follows is what started as my response to this comment. It was suggested that I post this as an answer on another question. I couldn't find one that fit, and I haven't made a blog post on here in a while, so I figured on putting it here. Edits and additions have been made to make the answer more complete.
I've read through the responses to your question and decided that you're not looking for a fight, so I'll try to try to answer your question from what I understand of the scientific viewpoint of the (origin of the) universe. If at any point I seem condescending, I do not intend to be; I simply don't know how much you know. Also know that this is based on what I remember of physics class and may be wrong. Please correct me if this is the case.
So people know about the Big Bang Theory. It's a wonderful TV show. Oh. Wait. Wrong Big Bang Theory. Humor aside, what I remember of my astrophysics course is that the universe - not the matter in the universe, but the “material” of spacetime itself, the “container” for matter, if you will - was much smaller than it is now. There was no matter, only energy. On the “bang” event, spacetime exploded outward and that energy began to convert to matter.
E=mc^2. Energy and mass (matter) are the same. In fact, particle physics is about how this works: when an antimatter hydrogen and a matter hydrogen collide, they turn into pure energy. The beginning of the universe was the opposite of this: energy splitting into matter and antimatter. Then that matter - hydrogen and maybe some helium - formed stars, which fused the elements into denser ones. Stars exploded and that matter formed planets, and so on.
First question: where did all of that energy come from? And what caused it to “blow up”? There are theories about this, such as that there had been a universe previously that collapsed on itself in a “Big Crunch” that led directly to another “Big Bang”, a universe, “Big Crunch”, “Big Bang”, and so on (honestly, I don't know if any physicists still call this a theory because of what I explain below, but I remember learning about the “Big Crunch” in elementary school).
The problem with this is related to the “shape” of the universe. Here is a link to a NASA page giving a short explanation on the shape of the universe. Basically, there is what is called the “critical density” of the universe. If the universe is more dense than this, it will eventually stop expanding and implode on itself - the “Big Crunch”. If the universe is less dense, it will expand forever. And if the universe is just at critical density, it will expand forever at a rate that slowly approaches zero (basically, given infinite time it will stop). I like to imagine this as the heat death of the universe, which I'm pretty sure follows the Second Law of Thermodynamics, at least as I understand it in saying that a closed system's energy will slowly be converted into unusable (heat) energy. Basically, all of the energy in the universe will eventually become useless and everything in the universe will be floating motionlessly in a massive graveyard. This is one of those things that I do not understand too well, however. So don't quote me on that.
Anywho, each type of density - greater than, less than, and equal to critical density - has a “shape”. You can read more about it on that NASA link, but here's the correlation:
- Greater than critical density: “Closed” or “Spherical”
- Less that critical density: “Open” or “Saddle-shaped”
- Equal to critical density: “Flat”
According to that NASA link…
We now know (as of 2013) that the universe is flat with only a 0.4% margin of error.
This is why we couldn't have had the Big Crunch: our universe just isn't dense enough. It couldn't have imploded and exploded again, so it must have “banged” only once and never again. Because of this, science has nothing to tell us about where that initial “bang” came from.
Now, Christians believe that God set up the initial conditions of the universe and the laws of science (physics, chemistry, quantum, and otherwise, both what we know and have not yet discovered) to set the universe into perfect balance into becoming the beautiful creation it is today. This includes creating the Big Bang.
Fast forward to Earth. This is where the book of Genesis really begins (the rest of the universe is verse one, creating “the heavens and the earth”). While some people believe that the 7 days of creation are literal blocks of 24 hours, others believe that each “day” was a series of thousands or millions of years. Thus these believers would believe that God guided evolution to create the species that exist today, including humans.
The next question is then: where did the original life come from? We were taught in biology class that living cells can only come from other living cells. If that is the case, where did the first living cell come from? Again, we believe that God is the origin of life.
The next logical question that would come from you would probably be one along the lines of “well how do you know that the God you are talking about is the one described in the Bible?”
This one is more complicated to explain. Honestly, it's a combination of logic and experience. For me, the actions of the God of the Bible through both old and new testament make logical sense. Furthermore, archeology has shown that the Bible is historically accurate, to the degree of there being an entire people group in the Bible that had not been discovered that atheists used as “evidence” that the Bible was false. Then archeologists discovered said people group, exactly where the Bible said they were. I had forgotten the name of this people group, but the link above says that they were the Hittites.
The historical record shows that Jesus and his followers (the 12 disciples) were greatly persecuted, tortured, and even killed for the beliefs they followed. The disciples especially were given the option to renounce what they believed, but they were so convinced of what they believed that they preferred to be killed than to renounce it. And the methods of killing - crucifixion, stoning, and so on - were not particularly quick or painless. So there must have been something about what they believed that caused them to be so devoted.
And consider that the same happened to Jesus. He was invited to dinners and such, but he also had no place to call his home. He didn't take peoples’ money and buy himself a mansion or fancy cars. The Pharisees wanted him dead. He taught what he believed (and I believe) to be true, including things that were so hard to take that most of his followers deserted him. He had influence over his followers by how he taught, but he did not ask for money for himself. He did not assume a position of political power, though most of his followers expected him to - that is what they believed the Messiah would do, followed immediately by overthrowing Rome. He did none of those things, yet he willingly went with the guards who came to arrest him. He did not lie to try to get out of dying. And to be clear, crucifixion is hours of pushing yourself up on the feet that are nailed to the wood to keep from suffocating. As your legs give out, pressure on your ribs cause it so that you cannot breathe and, well, you die.
So, these are the people who would have known that it was all a farce, and they all willingly died. People don't die for what they know is a lie.
On top of ALL of that, there are the personal experiences. For me, these are the coincidences that are so numerous and unlikely that it makes one think that they are not so coincidental. Moments of deja vu that are specific enough that it is not caused by performing similar actions multiple times (I've had those too) and so detailed that it's more than “this is kinda familiar”. Moments that I can only describe as God speaking to me; not in an audible voice, but words coming unbidden to mind or a sensation that is too powerful to ignore. It is hard to explain and really is something that must be experienced to understand.
It is a combination of all of the above that make me believe what I believe, both the experiences and the logic. Part of what I believe is that God created the universe. That is why I believe it.