Be careful when you say "only theorized." A well-supported scientific theory is the highest form of human knowledge. A scientific theory isn't just a hunch (the everyday meaning of theory), it's a combination of observational evidence, a careful explanation of the evidence, and some predictions based on the explanation that can be researched to expand the domain of the theory. And (very important) a basis for falsifying the theory, an observation that would prove the theory false.
The recent discovery of the Higgs boson is an example of theory confirmation -- it's based on the "standard model", the theoretical structure of modern physics, and the Higgs was predicted on theoretical grounds long before we had any chance to detect it.
As to "smart people only theorized", gravity has an explanation, and a very good one -- general relativity. Relativity is one of the two best-confirmed scientific theories we have (the other one is quantum theory, that makes our computers possible).
Please remember this when you want to say "only a theory".
Agreed. I loved Bill Nye's shows when I was a growing up, and I think he made a positive difference in my life. I don't know if participating in the debate will have had the same effect on anyone there.
I wish Bill would continue the kind of work he did when I was younger, instead of debating creationists, or going on FOX News to be the wacky scientist from that kids show that explains middle school science to the viewers.
Getting children interested in science. In discovery. Fostering a love of learning. That's what I think matters. That will be his legacy.