The short story of the apple hitting Newton on the head has been compiled into about 150 words.

Newton was under an apple tree one day, and a ripe apple fell and hit Newton on the head.

Newton was thinking: Why does the apple fall when it is ripe? Falling down? Instead of falling up?

Then continue to hypothesize: If the apple tree is as tall as the moon, then why does the moon not fall?

There must be a force pulling the moon. , so that the moon will not fall to the earth.

Finally, the famous law of universal gravitation was derived