Unexplained Phenomena - Language of Speculation

What is the difference between:
a fact - something that can be observed or measured and
a theory - a possible explanation that has not been proven

Watch the video and see which are facts and which are theories in these mysteries. What language of speculation are they using.
 Remember speculative words and phrases are often used such as:
may                             might              could
It seems/appears...       It´s possible...
We suspect...               We think/believe