I consider myself an agnostic atheist and I am interested in what lies outside the observable universe and what physicists have to say about other dimensions. That being said, as an amateur philosopher I have to concede that I do not know everything, so it helps to keep an open mind. What I do not understand is why atheists and theist get so heated over the existence or nonexistence of god/s. I try not to get too attach to my beliefs/opinions because, in the vain of B. Russell, they could be wrong. But like I said I am an atheist, so please do not think I think gods, heaven, etc. exists.
Lisa said, "I am interested in what lies outside the observable universe and what physicists have to say about other dimensions."
A current cosmological theory about other dimensions in the Universe is the Ekpyrotic Cosmological Theory. But there are no theories about what is "outside" the Universe and what was before the Universe. There is no "outside" the Universe or "before" the Universe. The Ekpyrotic Theory is that the Universe is a multi-dimensional brane. The idea is that there are more than four dimensions but we do not perceive them. They are folded up and never fully expanded. In this multidimensional Universe there are at least two branes. In hundreds of billions of years in our time these branes collide and cause a big bang and a Universe such as ours comes into existence. This is called the Ekpyrotic Theory. This theory was developed to solve the problems with the big bang theory. It eliminates the need for our universe to expand in the first moments faster than the speed of light, or the inflationary epoch. In this theory in the future the Universe expands to the point that it dissolves and becomes a brane and will collide with another brane and create another Universe.
We don't really know how many dimensions our Universe has but our current observations are at least 3 + 1 dimensions. The fourth dimension is time. Einstein realized that space and time are not separate things they are interwoven. The only quantum theory of gravity so far is string theory and the idea of additional spatial dimensions comes from string theory. A consistent description of gravity needs more than 3 + 1 dimensions. The theory is that the Universe could have as much as 11 dimensions, but if these dimensions exist we do not perceive them because they are very different from our three-dimension brane. We are confined to a 3-dimension brane in a higher level of space that is part of a multi-dimensional Universe.
In this theory the big bang that started the Universe expanding blew up only 3 dimensions of space and the other dimensions have not unfolded. That means that there are dimensions that are undiscovered. Equations that describe this theory would also require extra dimensions of space.
Lisa said, "as an amateur philosopher I have to concede that I do not know everything,"
I doubt that anyone knows everything. However, theists do not want to find answers they want to fill in the blanks with supernatural bullshit. That's why we have problems with them.
Lisa said, "so it helps to keep an open mind. What I do not understand is why atheists and theist get so heated over the existence or nonexistence of god/s."
I don't think atheists seek Christians or theists out to discuss their views; it's the other way around. Christians or theists use the open-minded argument when atheists reject their claims. It's all they have. They think keeping an open mind means accepting things for which there is no evidence. Atheists know that is not the case. Christians accept the story of creation and all the other fallacies in the bible on faith and not because they have an open mind.
Extraordinary claims require extraordinary proof. The burden of proof is on the one making the claims. The theists just never seem to understand that atheists do not have to prove anything since they are not making any extraordinary claims. When the theists or Christians prove something then they can call atheists closed minded bigots. I know that there is no proof of their claims as of right now. I also know that they do not listen to anything that contradicts what they already believe. Theists are not open-minded. Most atheists that I know do not reject things out of hand just because they have not yet been proven, but it has to be conceivable or even reasonable. The bible story about "god did it all" is simply absurd.