Good explanation Adamah. One small point - I'm not sure it's true to say that gravity is also a theory, it is a fact as you say. There may be theories about gravity.
The distinction between theories and facts is important, since the value of a theory is that they can explain facts (AKA confirmed observations), and theories even can provide us with some predictive value.
But as explained in the NCSE download, theories are actually more powerful than facts, since they serve as useful models that explain the facts. Theories may gain the stutus of becoming facts, such that scientists no longer feel the need to constant perform re-confirmatory experiments (although those facts are always subject to disconfirmatory challenge). Thus facts and theories are both subject to challenge at any time, since there are no "sacred cows" in science: show us the evidence for why a fact or theory is wrong, and both are potentially discarded IF the evidence is compelling enough AND can be repeated by others.
But back to your gravity example: there may be multiple 'theories' of gravity, but technically there is only ONE accepted theory as "the consensus opinion", and MULTIPLE hypotheses challenging it. That goes back to what I posted above about how evolution is on more solid ground as an uncontested theory within the life sciences than even gravity is for the physical sciences, i.e. there is more consensus opinion for the theory of evolution than even for the theory of gravity.
GromitSK said- I wouldn't say evolution is a fact although I do think there is a high probability it is a fact, especially compared to other hypotheses about how we got here. I might say evolution is a fact if I was better informed though :)
Science speaks in the language of probabilities, which is NOT the language of theology; there are NO absolutes in science, but only probabilities.
That said, the evidence pointing to the FACT of evolution is overwhelming such that it's proven well-beyond a reasonable doubt, and that conclusion IS the overwhelming consensus opinion of those working in life sciences. As stated elsewhere, without evolution, my field (biology) is simply a random collection of interesting facts that simply must be memorized but then need to be updated, when they are no long true due to changes. Those changes cannot be explained without the theory of evolution, i.e. God would have to be constantly changing life forms, which violates God's creating life "according to their kind" (as fixed "kinds") found in Genesis.