Tuesday, June 22, 2010

How Isaac Newton Discovered Gravity

In 1666, Isaac Newton, a young man from Trinity College, Cambridge, returned to his mother's countryside estate in Lincolnshire, where he would make an amazing discovery. One afternoon, Isaac strolled across the lawn and wondered why the grass was green and the sky was blue. He approached his mother's apple tree, and a shiny red apple caught his eye. It looked delicious. A powerful force urged Isaac to bite into the apple while it was still alive, its stem still attached to the branch. He knew it was a crazy urge, so he glanced around to make sure no one was watching. His mother's house was silent. So was the neighbors' estate. The road was empty. Isaac clutched the apple and lifted it to his lips. (This was long before germs were discovered, so Isaac didn't bother to wash the apple, or even polish it with his shirt.) He took a big bite, closed his eyes, and chewed the sweet apple pulp. It was as juicy and delicious as he had hoped. But the first bite was always the best—the bites after that weren't as good—so he released the apple, letting it dance and dangle on the branch. Isaac then sat down and leaned back against the apple tree trunk. He felt the sunlight dapple on his face, and he let himself get lost in thought. What was light? Why did it come from the sun? Why didn't clouds fall and crush people?
Isaac was in such a deep state of concentration that he didn't hear his mother approach.
“Isaac!”
“Oh, hello, mother.”
Isaac Newton's mother was a short, squat woman with a shrill voice.
“Isaac, what are you doing?”
“I'm thinking.”
“You mean you're daydreaming.”
“Yes, mother.”
“What's this?” She gripped an apple dangling from the tree. It was the apple that Isaac had taken a bite from. The inner part had turned brown. “Isaac, did you take a bite out of this apple?”
Isaac hung his head.
“Yes,” he admitted.
“Why?”
“I don't know.”
“Isaac, your poor father must be rolling over in his grave. All you do is mope around and daydream and ruin perfectly good apples. What would the neighbors say if they saw this? An apple still on the tree with a bite in it!” She plucked the apple from the branch and stuffed it in her apron pocket. “Do you know how embarrassing it is for me to have a son who mopes around all day and eats apples straight off the tree?”
A wave of depression swept over Isaac.
“Maybe I should just kill myself, mother.”
“Well, at least my apples would be safe.”
Isaac stood up and walked to the shed.
“Where do you think you're going?” his mother demanded.
Isaac didn't reply. Inside the shed, he picked up a coil of rope that was about five yards long. Then he walked back towards the apple tree, tying the rope into a noose.
“Don't you dare,” his mother said. “Not on my apple tree! I don't want you shaking all the fruit off the branches!”
Isaac had made enough of a mess while he was alive. He wanted to make the least amount of mess possible while dying, so he tried to calculate where on the thick branch to hang the rope and how long it should be in order that it would shake off as few apples as possible while still being sturdy enough to break his neck. Unfortunately, mathematics in 1666 wasn't advanced enough to solve this problem, so Isaac quickly invented a new method to solve it—differential calculus. Isaac's mind worked lightning fast, and within a couple seconds, he knew exactly where the rope should go.
“Don't worry, mother,” he said, tossing the noose over the thick branch. “I'll only knock down nine apples. You can bake a pie.”
“There's six apples in a pie, Isaac. I can't make half a pie. What am I supposed to do with the extra apples?”
“You can make apple tarts, mother.”
Isaac looped the rope around the branch, and knotted it tight.
“And who's going to eat them?” his mother asked. “You're the only one who likes apple tarts.”
Isaac climbed up the tree trunk, and crawled out onto the branch. He pulled the noose up, and slid it over his neck.
“Mother, you can put the apple tarts in my coffin. Ill take them to the next world with me.”
“Coffin? You don't deserve a coffin! You're getting a pauper's burial!”
Isaac wondered: When he tumbled off the side of the branch, why would he fall and snap his neck? Why wouldn't he fly up in the air or float like a cloud? What force was pulling him to the ground? The answer was suddenly obvious. The force pulling him down was his mother. She pulled everything down. If it wasn't for her, he could have been happy. She was the reason apples fell from trees. She was probably the reason the moon orbited the earth. There was one force that controlled everything. His mother. It was an amazing discovery.
“Goodbye, mother,” Isaac said.
He slid off the side of the branch, and fell.
“My apples!” his mother shrieked.
Isaac's neck caught on the noose, and cracked loudly. He hung dead from the tree. His mother covered her head, as nine apples rained down on her.