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This is massive space power facility in Cleveland, Ohio.

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And it is the world's biggest vacuum chamber.

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It's used to test space craft in the conditions of outer space.

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And it does that by pumping out the 30 tons of air in this chamber.

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Until there are about 2 grams left.

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This kind of got an eccentric construction which is powered it's history,

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it was built in the 1960's,

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as a nuclear test facility to test nuclear proportion systems

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and that meant that they build it out of aluminum

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to make the radiation easier to deal with.

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Aluminum is not the best thing,

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the strongest material to build a vacuum chamber

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so they build out of concrete skin

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which is power radiation shield and imparts an external pressure vessel

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so this thing can take the force present on the outside

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when it pumps out to the conditions of outer space.

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Galileo's experiment is simple,

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it took a heavy object and a light one

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and dropped them at the same time to see which fell fastest.

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♪

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Now on this case, the feathers fell to the ground

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at a slower rate than the bowling ball

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because of air resistance.

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So in order to see the true nature of gravity

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we have to remove the air.

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It takes three hours to compact the 800 thousand cubic feet of air

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for the chamber.

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Okay we drop two mil-liter in the last 30 minutes.

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But once it's complete there's a near

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perfect vacuum inside.

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6904, manual 10 percent open, station one go for drop.

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Male giving instructions.

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10, 9, 8, 7, 6, 5, 4, cameras on, 3, 2, 1, release.

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♪

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Laughing

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They came down exactly the same time.

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Exactly. Exactly the same.

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Issac Newton would say ,

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that the ball and the feather fall

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BEcause there's a force pulling them down, gravity.

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With Einstein would see imagine this scene differently.

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The happiest thought of his life was this.

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The reason the bowling ball and the feather

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fall together is because they're not falling,

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they're standing still, there is no force acting on them at all.

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♪

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A reason that if you couldn't see the background,

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that the no way of knowing that the ball and the feathers

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were being accelerated towards the earth.

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So it concluded they weren't.