You are here

Apollo 15, Part II

July 31, 2011

When Apollo 15 astronauts Dave Scott, Jim Irwin, and Al Worden visited the Moon 40 years ago this week, they conducted some high-tech experiments. They gathered rocks and soil, left instruments to measure moonquakes, and snapped hundreds of high-resolution pictures from orbit.

But as Scott and Irwin wrapped up their final moonwalk, Scott conducted a decidedly low-tech experiment -- one that was first envisioned almost four centuries earlier.

SCOTT: In my left hand, I have a feather. In my right hand, a hammer. And I guess one of the reasons we got here today was because of a gentleman named Galileo, a long time ago, who made a rather significant discovery about falling objects in gravity fields. And we thought, where would be a better place to confirm his findings than on the Moon...

Galileo's hypothesis was that gravity treats everything equally. So if you take away the air, which slows the fall of things like feathers, all objects should fall at the same rate. He tested his hypothesis by rolling balls of different sizes and weights down an inclined ramp and measuring how fast they rolled. As he suspected, there was no difference in their speed -- an indication that gravity acts equally on all objects, regardless of size.

SCOTT: And I'll drop the two of them here, and hopefully, they'll hit the ground at the same time.

And they did.

SCOTT: How about that? That proves that Mister Galileo was correct!

-- even with a low-tech experiment.


Script by Damond Benningfield, Copyright 2011


Get Premium Audio

Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.