# Is gravity an effect of inertia?

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This idea has occurred to me in the past but I never found much logic to support it. Now though it appears to me that this was also the result of an ancient science based on observation and logic. Mass can pre-exist gravity and inertia in another state such as energy but the means by which inertia can cause gravity is obscure to me.

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What logic is there that supports it?

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Is gravity an effect of inertia?

No

Consider a universe where there is a single particle with mass.

There is still inertia, measured by Newton's second law, but there is no gravity.

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What logic is there that supports it?

Isn't it true that the characteristics that all matter has is gravity and inertia and the only matter has gravity and inertia?

Isn't it possible one is the effect of the other? Where one exists the other must exist in equal proportion.

No

Consider a universe where there is a single particle with mass.

There is still inertia, measured by Newton's second law, but there is no gravity.

I'd be inclined to say that both gravity and inertia are undefined in a universe with no matter or only a single "piece" of matter.

If more matter were introduced then velocity and inertia could be defined and gravity would exist.

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I'd be inclined to say that both gravity and inertia are undefined in a universe with no matter or only a single "piece" of matter.

If more matter were introduced then velocity and inertia could be defined and gravity would exist.

If there was only one mass, m1 then Newton's second law

Finertial = m1a

Still holds. Why do you wish to deny it?

However Newton's law of gravity woul still hold, but

Fgravitational = km1m2/r2

so Fgravitational = 0 since m2 = 0

There is nothing inconsistent here to be a matter of opinion about..

If the equations said something different then I would report that.

Edited by studiot
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If there was only one mass, m1 then Newton's second law

Finertial = m1a

Still holds. Why do you wish to deny it?

However Newton's law of gravity woul still hold, but

Fgravitational = km1m2/r2

so Fgravitational = 0 since m2 = 0

There is nothing inconsistent here to be a matter of opinion about..

If the equations said something different then I would report that.

You're making numerous assumptions here.

Perhaps the easiest way to show it is to simply ask if the outside of the mass

you are postulating to exist is being attracted by the inside through gravity.

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I've simply applied the theory based on the mathematical principle that if an equation holds for all x then it must hold for any particular value I choose.

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I've simply applied the theory based on the mathematical principle that if an equation holds for all x then it must hold for any particular value I choose.

I trust you'll have a lot of difficulty showing this experimentally.

How can you determine that your mass has inertia if it's the only thing in the

universe? How can inertia even be defined if its state, position, and speed can't

be determined?

In a vacuum wouldn't a molecule revolve around it's center of gravity? If there

were a universe with a single spinning mass would it revolve around its center

of gravity?

Since we don't know the nature of gravity then how can we say that the outside

of a subatomic particle isn't attracted to the inside? Perhaps we don't know the

nature of gravity and electo-magnetic forces because we misunderstand some

basic concept.

Maybe it's just me.

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Isn't it true that the characteristics that all matter has is gravity and inertia and the only matter has gravity and inertia?

Isn't it possible one is the effect of the other? Where one exists the other must exist in equal proportion.

I'd be inclined to say that both gravity and inertia are undefined in a universe with no matter or only a single "piece" of matter.

If more matter were introduced then velocity and inertia could be defined and gravity would exist.

Sounds a little like Mach's principle (or conjecture)

http://en.wikipedia.org/wiki/Mach's_principle

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Why can't it's state, position and speed be determined?

I define it to be 1kg mass and travelling at 100mph along the y axis.

I then ask to calculate the force required to accelerate it to 200mph in 10 seconds.

If you really don't like my example, then try this one where the object is not the only thing inthe universe.

Place a point mass, mass m, ( a perfectly respectable object in theoretical mechanics)

Place it at the exact centre of a uniform spherical shell of total mass M and diameter 1000 metres.

What force is required to displace this mass from the centre and accelerate it in any direction at 1m/s2?

Edited by studiot
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Sounds a little like Mach's principle (or conjecture)

http://en.wikipedia.org/wiki/Mach's_principle

"...inertia originates in a kind of interaction between bodies..."

I think you may be on the right track.

Perhaps it's inertia which is inate, related to time, and that causes gravity.

Why does time exist in the relationship between matter and energy? Is the speed of light held back by the weight of the photon?

I suppose I'm rambling...

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"...inertia originates in a kind of interaction between bodies..."

I think you may be on the right track.

Perhaps it's inertia which is inate, related to time, and that causes gravity.

Why does time exist in the relationship between matter and energy? Is the speed of light held back by the weight of the photon?

I suppose I'm rambling...

Thanks, but I'm not Mach, and as far as I know it is unproven conjecture....metaphysics that may have helped toward the General Theory of Relativity. Your statements seemed to be directed along similar lines of thinking.

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I should just point out that Mach's principal was a strong driving force of Einstein's initial concept of general relativity. However, general relativity does not properly obey Mach's principal.

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Isn't it true that the characteristics that all matter has is gravity and inertia and the only matter has gravity and inertia?

Isn't it possible one is the effect of the other? Where one exists the other must exist in equal proportion.

I'd be inclined to say that both gravity and inertia are undefined in a universe with no matter or only a single "piece" of matter.

If more matter were introduced then velocity and inertia could be defined and gravity would exist.

Inertia could be seen as more of a fictional property. The object would continue at it's current velocity if there were no net force on the object. It is not an inherent property.

Gravity is not an property of matter. Where did you get that idea? In a vacuum very far from any other masses(You can choose many massive objects to show this), the massive object will experience no effects of gravity. Does the matter still exist as matter? Yes. It does not need gravity to prove it is matter.

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