To Ruby, regarding the age of the earth:
The first thing you should realise about this issue is that in the scientific community it is pretty much universally accepted that the earth is billions of years old, based on the evidence available. So the "debate" you mention in some of your posts isn't really a debate between experts in a particular field, as normally happens in science.
Instead, what has happened, especially in the U.S., is that some people have decided that an old earth is incompatible with their religious views, so have decided to attack the scientific concensus. In other words, they start from the view that Bible is inerrant and that the creation account in book of Genesis should be read as being literally true. Since this kind of reading of the bible would imply a relatively young earth (less than about 10 000 years) then this would mean modern estimates of the age of the Earth would be false.
Note that this argument relies on a particularly view of the bible (one which is not the majority view even amongst Christians, BTW), not on the evidence from scientific studies. Unfortunately, many "Young Earth Creationists" have tried to put a scientific spin on their religious views (in order, amongst other things, to get their ideas taught in schools). Some of their "scientific" arguments can sound quite plausable, and have convinced many people, so I certainly don't think you're stupid for perhaps being taken in by some of them

But you should know that their arguments have failed to convince the mass majority of scientists, especially in the relevant fields (mostly geology and astronomy).
Anyway, all of this is besides the point, and is my own personal take on the subject FWIW. The important thing is that if you're interested in the topic, that you look at the evidence as carefully and objectively as you can, and make up your own mind. The links others have posted will be useful as starting points. The link I've posted below also discusses perhaps the best way of dating the age of Earth, through radiometric dating of rocks. I'm afraid it can be pretty heavy reading at times, but I think it's worth slogging through it. And I'm sure if you have any questions at least some people who hang around these boards will be able to answer them.
Good luck!
http://www.asa3.org/ASA/resources/Wiens.html