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Gravity

1234 said:
This is all based on calculations that are the results of experiments done on the Earth. They were not done on different planets simultanesiouly
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What in tarnation does this have to do with anything?
 
1234 said:
This is all based on calculations that are the results of experiments done on the Earth. They were not done on different planets simultanesiouly
Click to expand...

Are you suggesting that the behavior (for lack of a better term) of gravity differs from planet to planet?
 
1234 said:
This is all based on calculations that are the results of experiments done on the Earth. They were not done on different planets simultanesiouly
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Actually, these equations are used to calculate the orbits of the planets of the solar system around the sun, the orbits of moons around those planets, the orbits of binary star systems, the orbits of stars in our galaxy and others, and the orbits of galaxies in galaxy clusters. As far as we can see, and that is very, very far indeed, they are correct everywhere- and I do mean everywhere. No violation of them has been seen, other than minor corrections for General Relativity. In fact, conclusive and replicatable proof of a violation would result in a Nobel Prize for the prover, a strong incentive. I think you can take it as given that they are as nearly correct as makes no difference.
 
new drkitten said:
Not so much "incorrect" as "oversimplified."

When I drop a hammer, the Earth moves up to meet it. (Action and reaction -- just as the hammer is moved by the Earth's gravity, so is the Earth moved by the hammer's) Not, granted, by very much. I'm probably justified in ignoring the movement of the Earth unless I want to be pedantically accurate.

If I drop an anvil, the Earth moves up to meet it, too. And since the anvil is more massive, the Earth experiences a greater force and moves up more. So the anvil will technically strike the Earth after slightly less time than the hammer would.

And, of course, if I drop a planet on the Earth, the planet would cause the Earth to move significantly.
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Just so everyone else is clear (I'm sure drkitten and Pragmatist are) the difference in the hammer vs. anvil case here is almost certainly unmeasurable for reasonable falling distances (hundreds or perhaps even thousands of feet). But to be nitpickingly technically accurate, yes, there is a slight difference in the falling time, based on the equations.

It is probably worth noting that Galileo overturned Aristotle's long-standing fallacy stating that heavier objects fall a lot faster than lighter ones by showing that the difference is in fact so small as to be unmeasurable; again, this is within the limits of reasonable accuracy, and I do not dispute Pragmatist's analysis.
 
Christ, this is why I don't read this board anymore. The answer to every simple question requires a PhD to explain and understand.

It's no wonder religious folk hate skeptics.
 
As far as I can tell, 1-4 has just stated something we already knew: A bowling ball dropped on the earth will fall faster then a bowling ball dropped on the moon.
 
1234 said:
I just wanted to say that if two objects that had the same mass while an artificial gravitational field was pulling on the smaller ball if it was rolling down a ramp at the same time as a bigger ball, then the smaller ball would roll down first if the artificial gravitational field was strong enough. For example, if a ball was dropped on the moon at the same time as a smaller one was dropped on earthm then the one on the Earth would fall faster relative to the smaller ball on the moon.
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I'm glad you finally got that off your chest. That was quite a burden you were carrying.

You know, I've always wondered what type of person sends in those crackpot "proofs" of Fermat's Last Theorem to famous scientists.
 
1234 said:
This is all based on calculations that are the results of experiments done on the Earth. They were not done on different planets simultanesiouly
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Well, as a matter of fact, there are a good number of planets that are permanently being 'dropped' around the Sun, if you like to think of it that way.

If you're suggesting corrections or modifications to gravity (and I'm not sure that you are), nothing but a minute modification is going to work since gravity is so well tested on bodies large and small (google 'MOND' for more info on current theories of modifying gravity).
 
StaticEngine said:
Christ, this is why I don't read this board anymore. The answer to every simple question requires a PhD to explain and understand.
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Actually, this one requires a sixth-grade education.

StaticEngine said:
It's no wonder religious folk hate skeptics.
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Religious folk hate skeptics because the meme they've been infected by causes them to, to protect itself. If it didn't, it wouldn't survive long.
 
1234. Have you ever seen the film of Dave Scott (Apollo 15) dropping a feather and a hammer on the moon?

They fall at the same rate (as each other).

The same experiment on Earth would require a vacuum chamber to get rid of air resistance. They would fall faster because of the higher gravity. They would still fall at the same rate as each other- just faster than on the moon.

If there is something beyond this you are trying to say, I'm sorry, but I have not understood you.
 
What I'm saying is, it doesn't matter if you're technically right if you can't communicate it in a simple manner.

Throwing lots of extraneous details into the mix just pisses people off.
 
StaticEngine said:
What I'm saying is, it doesn't matter if you're technically right if you can't communicate it in a simple manner.

Throwing lots of extraneous details into the mix just pisses people off.
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What extraneous details?
 
The deal about the mass of the body affecting the planet, and then the posts with ten paragraphs of equations. The question was simple, will two objects dropped different planets with different masses fall at different rates? The answer is simple, yes, and the simple explanation that different massed planets will have different gravitational fields, and that acceleration of relatively small objects due to falling is totally reliant on those fields and not the masses of the objects, is plenty to suffice.

If someone asked the question on the street and I started spouting equations for ten minutes, they'd lose interest and get annoyed. But if I gave them a technically correct but simple answer in 20 seconds, they'd say thank you with a smile, and be satisfied.

Simple and clear communication is so important to winning someone over, and really, that's why religion tends to win over so many people even though science is right: because scientists tend to be poor communicators to those not already learned in science, or those with short attention spans. If we had more scientifically minded people who could speak clearly and simply, I believe we'd have a society more accepting of science.
 
The question posed in the OP, once clarified, was adequately answered in two posts. Answered, I might add, in terms most 12 year-olds should be able to understand.

The balance of the thread was, I thought, an interesting and educational discussion of the subject at hand, no part of which was difficult to understand. If 1234 was not getting anything out of it he/she need only stop reading. The OP was answered by post #9.
 
If someone dropped a bowling ball on the Moon at the same time someone dropped a marble on the Earth, then the marble would fall faster because you weigh less on the Moon then on the Earth. There are ways that you can find out how much you weigh on the Moon as compared to the Earth.
 
1234 said:
If someone dropped a bowling ball on the Moon at the same time someone dropped a marble on the Earth, then the marble would fall faster because you weigh less on the Moon then on the Earth. There are ways that you can find out how much you weigh on the Moon as compared to the Earth.
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Because the Earth is more massive, ANYTHING would experience a greater force and so would experience greater accelleration. So, disregarding the effects of air resistance, a feather on Earth would fall faster than a bowling ball on the moon, an elephant on Earth would fall faster than a bowling ball on the moon.

So the greater the force you apply, the more something accellerates.
 
1234 said:
If someone dropped a bowling ball on the Moon at the same time someone dropped a marble on the Earth, then the marble would fall faster because you weigh less on the Moon then on the Earth. There are ways that you can find out how much you weigh on the Moon as compared to the Earth.
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Yes. So?
 
Yes. So?

Was Galelio right about two objects falling at the same time if one falls on the Earth and one falls at the Moon at close to the same time?
 
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