The other night with my 4-yr-old granddaughter, we gazed up at the bright half-moon, and I asked her this question, "Why doesn't the moon fall down?"

I half expected her to say something like "Heavenly Father put it there." But she simply looked at me with a smile and said "Gravity."

I wondered at that moment if she'd ever heard that, or if she just "knew" it. Either way, she's right:

"The Sun's gravitational pull keeps our planet orbiting the Sun. The motion of the Moon is affected by the gravity of the Sun AND the Earth. The Moon's gravity pulls on the Earth and makes the tides rise and fall every day." (From www.physics4kids.com)

Smart girl. Proud PapaKen.

Wouldn't the correct answer be more like the velocity or motion of the moon and earth keeps them apart, and the moon not "falling down"?

Since if the planet and moon stopped moving, then gravity would make the moon fall down to earth in a fantastic kaboom.....

For a four-year old, I'd venture her answer is astounding.

Children are very smart for their years I've been noticing in the generations coming up.

She's precocious. You'll need to keep an eye on her, but she's off to a real good start.

:)

Okay, I know this is just a nitpic but, the actual term is...

https://en.wikipedia.org/wiki/Centripetal_force

Smart Girl you have PapaKen

cognitivedissonance Wrote:
-------------------------------------------------------
> Okay, I know this is just a nitpic but, the actual
> term is...
>

Damn, I couldn't remember the term. All those years studying physics clearly didn't stick......

Yeah, it's not actually gravity that keeps it from "falling down." That doesn't lessen the youngster's thinking -- she eschewed a magical answer, and went with real things. She can learn about motion, conservation of angular momentum, matter bending space-time, and centripetal force as she grows.
I think she did great :)

sorry folks, but it is NOT gravity or the centripetal force that it provides in the orbital arrangement that prevents the moon and and the earth from converging. If they had their way, the bodies involved would come together and would make contact. It's inertia and the centrifugal force that it provides to the moon that prevents the earth and the moon from coming together in spite of the gravity involved.

So who wins? God or gravity?

gravity is content to exert its influence regardless of the outcome, including the extermination of the human race or not, and it does so very consistently. so "winning", whatever that might be, does not mean that much to it.

What God wants? he very seldom says so directly. his will is almost always conveyed through a prophet, a intermediary who always seems to have a very subjective personal interest in the outcome. In the case of a MORmON prophet, your darling 4 year old grand daughter could be marriage material for them in just 10 more years. for a muslim prophet, in even less time.

Are you guys all kidding?

The kid's 4 years old. Gravity is a beautiful answer for somebody even twice her age. She's already grasping that the world isn't operated by magical levers pulled by a benevolent (and sometimes not so much) sky daddy. Hoorah!

And I thought I was curmudgeonly.



Edited 1 time(s). Last edit at 11/24/2015 06:28PM by schlock.

(Oh, and BTW, centrifugal force is generated by the moon's tendency to remain in motion in a given direction and at a given velocity, and centripetal force is generated by the earth's gravitational pull on the moon.)

http://www.diffen.com/difference/Centrifugal_Force_vs_Centripetal_Force

Should we *REALLY* quibble, and point out that there is no "gravitational pull" at all -- that it's the earth's mass warping space-time in the moon's vicinity, causing it to move along a curved path instead of straight ahead?

Nah. Let's allow the 4 year old her fun :)

Or point out that both the gravitational field, and the electromagnetic field, change instantaneously - not constrained by the speed of light.

https://en.wikipedia.org/wiki/Speed_of_gravity



Edited 1 time(s). Last edit at 11/24/2015 07:38PM by schlock.

and not only moving on a curved path, but in a flight following the solar body as it moves thru space, with the planets and their moons describing spiral vortices in its wake.

Albert Einstein, "If you can't explain it to a 6 year old, you don't understand it yourself."

Since she's 4, she gets some slack. ;o)

She obviously had picked up some of that godless secular learnin' from the interwebs and Jesus will make her burn in hell for it.
;^)

4 year old granddaughter needs to give a physics lesson to Bill O'Reilly.


https://www.youtube.com/watch?v=wb3AFMe2OQY