On October 14, 1971, during the final lunar EVA of the Apollo 15 mission, astronaut David

Scott stood in front of the camera holding two objects. In one hand was a hammer, and the other was a feather, and he was about to conduct an

experiment, a very simple one.

He held the hammer and feather out each the same height above the lunar surface.

And then he let them go.

The hammer and feather fell and struck the ground at the exact same time.

Now, of course, if you were to repeat this experiment on the earth, you would not get the same

result, and that's because of air resistance.

The hammer would go straight down while the feather would take its sweet time.

But on the moon, no air, no problem,

no difference. There was no difference between the feather and the hammer. And the origins

of this experiment go all the way back to 1589 with Galileo himself. Now, his student popularized

a story of him dropping balls of different weights from

the famous Leaning Tower of Pisa. Galileo almost certainly didn't actually do that. The old man

generally preferred rolling balls down inclined planes to better control and measure his experiments,

but the result is the same. His experiments disproved a long-held belief,

and I mean long-held, like thousands of years-long-held belief from the days of Aristotle,

that heavier objects fell faster because heavy meant, I really like being on the ground,

and if you're heavier, that means you like being on the ground even more.

And if you like something more, you're going to work harder to do it.

But this was wrong.

And Galileo showed that.

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