Truly speaking Science as such could not define a lot of things in the universe. But it is the flexibility of Science that helps it modify itself or generate new concepts to explain those phenomena and predict the further outcome to assertain the theory. That is where hypothesis comes into existance.
FOr example the concept of relativity was not there as long as there was MM experiment and Lorentz transformation, there was no quantum mechanics as long as photo-electric effect was discovered and Schrodinger's equation came into existance. The older concept of matter completely changed with quantum theory, e.g. tunneling effect of particles and so many other examples.
But it is Science which accepts the observations, tries to explain with the existing theory, and if not possible, derives at new concepts and validates them.