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Video Transcript:

What Does the Vacuum of Space Look Like?

Alexandra: Here on Earth, we are used to seeing feathers drift gently to the ground. On the other hand plummet is probably a better word to describe a falling hammer (drops hammer and feather).

They fall at different rates on Earth because the feather has a small mass compared to its surface area, while the hammer has a larger mass-to-surface-area ratio.

It takes a while for the feather to push air molecules out of the way during its fall. The hammer can push them out of the way - and therefore fall - much faster.

Now what if you could get rid of those air molecules? That's what a vacuum is - the absence of matter.

It's A VOID, ZILCH! ZIPPO! NADA!

You can't actually see what a vacuum looks like, but you CAN see how objects behave in a vacuum.

Let's go to the moon, where a near perfect vacuum surrounds the surface, and see what happens with our hammer and feather.

(Dave Scott, Apollo 15, on the surface of the moon drops hammer and feather). As they drop, the moon's gravity pulls them both in at the same rate of acceleration, and since all those tiny air particles which would normally hinder their fall aren't there, both objects hit the moon's surface at the same time.

Discover more at nasa.gov.

End of Transcript

NASA Brain Bite BB0901B

 
Feedback/questions: brainbites@nasa.gov

Curator: Kim Dismukes | Responsible NASA Official: John Ira Petty | Updated: 12/07/2004
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