01Feb2018

Newton And That Apple

Newton

There’s more to gravity than apples falling from trees.

For a long time I thought the story of Newton and the apple was just another fable. I thought it was a made-up story, like Washington chopping the cherry tree. Its not.

Cambridge University closed down in the Summer of 1665 when the plague broke out. Newton, a student there, went home to Lincolnshire. He stayed home for two years while the disease ran its course in the area around London.

The 23-year-old Newton spent that time studying and laying the foundations for his greatest work, the Principia. One day he sat thinking in his garden, when an apple fell. Then he realized. The direction the apple fell, along with every other object on this round earth, was always toward Earth’s centre.

It wasn’t just that the apple fell, but that it tried to go to Earth’s center. That was Newton’s Eureka Moment. He realized that Earth had drawn the apple to it. He realized that every object in the universe draws every other object — probably in proportion to its mass.

Newton didn’t publish his Principia until 20 years later. But he formulated the Law of Universal Gravitation there in his Lincolnshire garden. He showed us that what was true of apples and the earth was true of planets and moons as well.

Now enter a surprising character. The person who popularized the apple story was none other than Voltaire. The French Voltaire sided with Newton in Newton’s bitter fights with Leibnitz. Voltaire’s brilliant mistress, the Marquise du Châtelet, created the first French translation of the Principia while Voltaire was writing Candide. In Candide Voltaire ridiculed Leibnitz. The character Dr. Pangloss, who went about insisting that we live in the “best of all possible worlds,” was Voltaire’s version of Leibnitz.

We might chalk Voltaire’s apple story up to partisan license. But the story has good corroboration. Newton told it to close friends, who also recorded it for us.

If you’ve ever done anything creative, you’ll recognize the plausibility of the apple story. You’ll remember your own moment when some small and commonplace event revealed a great truth to you. That’s the way creativity works. It’s almost always the recognition of a great truth out of context.

Why did I so mistrust the apple story when I first heard it? No doubt it was simply too pat. For that apple of knowledge in Newton’s garden of Eden changed our science — and it changed our very lives. Engines Of Our Ingenuity

So…Why Does The Apple Fall?

http://www.bbc.co.uk/schools/gcsebitesize/science/images/13_gravity546.jpg

Gravity acts in all directions at the same time, pulling everything to the centre.

The answer is gravity. Most people know that gravity is what keeps us fixed to the ground, but in truth it is far more interesting than that. Gravity is a field permeating the universe, it does keep you connected to the ground, but it also keeps the Moon around the Earth, the Earth around the Sun and the Sun in our galaxy.

Gravity is the pulling force between two objects that have mass. But doesn’t that mean that humans have their own gravity, why don’t things fall towards us? Well, yes we do have our own gravity. But it is much too small to be noticeable.

http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2009/09/gravity.jpg

The gravitational field can be thought of like a taut sheet

The sun keeps the solar system in check, but how does it work? The biggest source of gravity in our solar system is the Sun. It weighs about 1, 989, 000, 000, 000, 000, 000, 000, 000, 000, 000 Kg. Thats about the same as 20 Octillion Bowling Balls! The sun is so heavy that it collapses under its own gravity. It squishes in on itself so hard that the tiny little atoms that make it up start to join together. As these atoms fuse they release huge amounts of energy which makes the sun shine incredibly bright and heat up the Earth. This means that the brightest thing in the sky is only bright because of gravity!

There is another phenomena that owes itself to gravity, a darker, more mysterious object. The Black Hole. A Black Hole is what happens when something becomes so heavy that its gravity is enough that it can pull light inside itself and trap it forever. They are formed by dead stars collapsing in on themselves. Black Holes are so dense that the normal laws of physics start to bend as you enter them. Time becomes longer, your body stretches out, you get faster and faster until you enter the centre. What happens at the centre of a black hole is a mystery that even the top physicists in the world are confused by.

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