The scientists who contributed to the understanding of the universal law of gravitation are:
- Sir Isaac Newton (formulated the law of universal gravitation)
- Johannes Kepler (his laws of planetary motion influenced Newton)
- Robert Hooke (his work on gravitational attraction contributed to Newton's theories)
Tycho Brahe, Albert Einstein, and Nicolaus Copernicus also made significant contributions to astronomy and physics, but they were not directly responsible for the formulation of the universal law of gravitation in the way that Newton, Kepler, and Hooke were.
So, the correct answers are:
- Johannes Kepler
- Sir Isaac Newton
- Robert Hooke