The Science of Alagaësia at the time of the Rider War was mostly medieval, but certain elves and dragons had discovered science of a level of advancement similar to that of Earth in the early 20th Century.
Inheritance described another paragon of science, albeit briefly: the theory of relativity. It is described as Glaedr mentions the devastation wrought on Vroengard when the Rider Thuviel converted his body matter into pure energy. Glaedr stated this as equivalent to matter being frozen energy. This is not entirely true but does somewhat match to the concept of Mass-Energy equivalence described in the famous equation E = mc².