Is it ensure, insure, or assure?
An Italian scientist of the late sixteenth and early seventeenth centuries; his full name was Galileo Galilei. Galileo proved that objects with different masses fall at the same velocity. One of the first persons to use a telescope to examine objects in the sky, he saw the moons of Jupiter, the mountains on the moon, and sunspots.
Note: Authorities of the Roman Catholic Church forced Galileo to renounce his belief in the model of the solar system proposed by Nicolaus Copernicus. Galileo had to assert that the Earth stands still, and the sun revolves around it. A famous legend holds that Galileo, after making this public declaration about a motionless Earth, muttered, “Nevertheless, it does move.”