2. Who’s Sir Isaac Newton? Isaac Newton was a English scientist, astronomer, and mathematician. He was born in 1642, and died in 1727.
3. His theory? One day, Newton was sitting under an apple tree, eating an apple and reading about the Universe. Suddenly, - Boink!- an apple hit him on the head. It fell from the apple tree above.
4. In a flash, he understood that the very same force that brought the apple crashing toward the ground also keeps the moon falling toward the Earth and the Earth falling toward the sun: gravity.