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Astronomy Picture of the Day -- Hammer Versus Feather on the Moon
NASA ^ | November 01, 2011 | (see photo credit)

Posted on 11/02/2011 3:14:29 PM PDT by SunkenCiv

Explanation: If you drop a hammer and a feather together, which reaches the ground first? On the Earth, it's the hammer, but is the reason only because of air resistance? Scientists even before Galileo have pondered and tested this simple experiment and felt that without air resistance, all objects would fall the same way. Galileo tested this principle himself and noted that two heavy balls of different masses reached the ground simultaneously, although many historians are skeptical that he did this experiment from Italy's Leaning Tower of Pisa as folklore suggests. A good place free of air resistance to test this equivalence principle is Earth's Moon, and so in 1971, Apollo 15 astronaut David Scott dropped both a hammer and a feather together toward the surface of the Moon. Sure enough, just as scientists including Galileo and Einstein would have predicted, they reached the lunar surface at the same time. The demonstrated equivalence principle states that the acceleration an object feels due to gravity does not depend on its mass, density, composition, color, shape, or anything else. The equivalence principle is so important to modern physics that its depth and reach are still being debated and tested even today.

November 01, 2011

(Excerpt) Read more at 129.164.179.22 ...


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; apollo; astronomy; science
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[Credit: Apollo 15 Crew, NASA]

1 posted on 11/02/2011 3:14:39 PM PDT by SunkenCiv
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To: brytlea; cripplecreek; decimon; bigheadfred; KoRn; Grammy; married21; steelyourfaith; Mmogamer; ...

2 posted on 11/02/2011 3:16:59 PM PDT by SunkenCiv (It's never a bad time to FReep this link -- https://secure.freerepublic.com/donate/)
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To: SunkenCiv
Watching "The Universe" last night and I think we need an Amy Mainzer rule for space threads.

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3 posted on 11/02/2011 3:18:48 PM PDT by cripplecreek (A vote for Amnesty is a vote for a permanent Democrat majority. ..Choose well.)
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To: SunkenCiv

We never went to the Moon.

/x-files music


4 posted on 11/02/2011 3:24:57 PM PDT by VanDeKoik (1 million in stimulus dollars paid for this tagline!)
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To: cripplecreek
This Amy Mainzer?


5 posted on 11/02/2011 3:29:38 PM PDT by Paladin2
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To: SunkenCiv

So let me get this straight.... If you dropped Obama and Biden’s brain at the same time....

Oh never mind.


6 posted on 11/02/2011 3:29:38 PM PDT by Bullish (Recovery won't begin until Obama loses HIS job.)
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To: VanDeKoik

7 posted on 11/02/2011 3:32:24 PM PDT by gargoyle (...it becomes necessary for one people to dissolve the political bands which have connected them...)
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To: Bullish
So let me get this straight.... If you dropped Obama and Biden’s brain at the same time....

Yes, you got it, they'd both float

8 posted on 11/02/2011 3:35:34 PM PDT by stormhill
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To: Bullish

That would be like dropping Santa Claus and the Tooth Fairy at the same time.


9 posted on 11/02/2011 3:38:17 PM PDT by DuncanWaring (The Lord uses the good ones; the bad ones use the Lord.)
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To: cripplecreek

It’s a good idea, because the only way I could get anything out of that show would be to listen and not watch. ;’)


10 posted on 11/02/2011 3:56:23 PM PDT by SunkenCiv (It's never a bad time to FReep this link -- https://secure.freerepublic.com/donate/)
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To: VanDeKoik

;’)


11 posted on 11/02/2011 3:56:41 PM PDT by SunkenCiv (It's never a bad time to FReep this link -- https://secure.freerepublic.com/donate/)
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To: Paladin2

When she was written out, the show passed its peak. Still like it though.


12 posted on 11/02/2011 3:57:40 PM PDT by SunkenCiv (It's never a bad time to FReep this link -- https://secure.freerepublic.com/donate/)
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To: Bullish; stormhill; DuncanWaring
Image and video hosting by TinyPic

13 posted on 11/02/2011 4:00:54 PM PDT by SunkenCiv (It's never a bad time to FReep this link -- https://secure.freerepublic.com/donate/)
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To: SunkenCiv

The hammer will fall slightly faster, as every mass has it’s own gravity. The hammers greater mass has greater gravitational pull on moon.


14 posted on 11/02/2011 4:06:10 PM PDT by SampleMan (Feral Humans are the refuse of socialism.)
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To: Bullish
>"If you dropped Obama and Biden’s brain at the same time..."

You'd be stoned stupider than Ozzy.

15 posted on 11/02/2011 4:07:42 PM PDT by rawcatslyentist (It is necessary that a person be born of a father who is a citizen; ~Vattel's Law of Nations)
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To: SampleMan
The hammer will fall slightly faster, as every mass has it’s own gravity.

I hadn't thought of it that way but it does make some sense. You would need a very long fall to show the difference to the naked eye.
16 posted on 11/02/2011 4:10:31 PM PDT by cripplecreek (A vote for Amnesty is a vote for a permanent Democrat majority. ..Choose well.)
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17 posted on 11/02/2011 4:44:47 PM PDT by RedMDer (Forward With Confidence!)
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To: SampleMan
The hammers greater mass has greater gravitational pull on moon.

That's true, but the "greater gravitational pull" is balanced by that fact that there's a greater mass to be accelerated.

18 posted on 11/02/2011 4:46:33 PM PDT by DuncanWaring (The Lord uses the good ones; the bad ones use the Lord.)
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To: Bullish

“Brain’’? Obama and Biden!?! What makes you think either of those two have a brain?


19 posted on 11/02/2011 4:50:49 PM PDT by jmacusa (Political correctness is cultural Marxism. I'm not a Marxist.)
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To: DuncanWaring

Also true.

You could move a supermassive black hole with a feather if you could anchor the feather somehow and had a few billion years to do it in.


20 posted on 11/02/2011 4:56:02 PM PDT by cripplecreek (A vote for Amnesty is a vote for a permanent Democrat majority. ..Choose well.)
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