Well, "we" say Jovian, while "they" say Jupiterian, though they're not yet convinced that our kilograms are the best.

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Credibility is simply incredible... sometimes even to me.
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This PhysicsReview article The Weight of Light says light gravitationally redshifts, as measured in 1960 Harvard experiment by Rebka and Pound, at the rate of 10^-15, which is the pure gravitational effect, and which matches Einstein's prediction with 10% accuracy.

Does this mean this "classic test of relativity" that photons of light or gamma rays have "mass" to cause gravitational interaction? Or does it mean something different, that gravitational forces cause redshift, a lengthening in wavelength, which then mimmics light having mass? In this part 1 post, I show an example of pure gravitational redshift, without relativistic considerations, while in part 2 post I show how light "cut-off" wavelength may account for this greater gravitational effect through most of intergalactic deep space.

If light, or any em energy, has no "mass" as we know it, then can the natural gravitational redshift of such energy account for what "mimmics" mass in the gravitational bending of light? And if this is so, then is this gravitational bending of light a valid test of Relativity? This of necessity raises the question as to what exactly is "mass".

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Credibility is simply incredible... sometimes even to me.
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Keep in mind that just because a question is raised doesn't mean that you are the one with the answer.

See, you make the classic mistake that you are the only one who is open-minded. Nothing could be further from the truth. I think I can speak for everyone here when I state that we would be enthralled with a modified theory of gravity. If someone showed that G was variable and that observation X, Y, and Z were now better explained by their new theory, we'd be overjoyed.

But your theory doesn't explain anything. You are unable to provide calculations that predict anything of any usefulness. Your theory predicts that objects of known mass weigh the same on Jupiter as our theory predicts they would. Your theory predicts the same orbits for Jupiters satellites as our theory does. YOU are unable to present any calculations. How can anyone claim to have a new theory of gravity without being able to perform the most basic physics calculations???

Here's my suggestions: when you can use your theory to calculate anything, then come back and let us know. Otherwise, we're all just babbling, and this is the wrong forum for that.

Nutant, in GR gravity doesn't couple with "mass" (note that "mass" in this post is some solid object, the way most people think of it), gravity couples to the stress-energy tensor. It's the amount of rest energy and stress (think pressure in this instance) that causes the curvature of space. Photons have energy (heck, that's what their definition is: energy quanta), but only when they are moving, so they have no rest energy. "Massive" particles (like planets, particles etc) do have a rest energy and thus can cause a curvature of space.


In GR zero rest mass particles paths are on null geodesics, the shortest path, timewise, through space. The bending of that path is what we observe as the bending of space-time.

Yes, it is a valid test.


That is the tricky part. Which is why GR uses the rest energy of the object. You can figure out the rest energy of a "mass" by multiplying the "mass" by c^2.

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Some try to tell me, thoughts they cannot defend,... - Moody Blues.

Did you understand what this sentence, my earlier, actually meant?

"The mass on Jupiter, for equivalent mass on Earth, would have for each molecule 5 times the gravitational force, so it would take 1/5 th as many molecules on Jupiter to equal one Earth kilogram."

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Credibility is simply incredible... sometimes even to me.
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I understand it completely. Once you postulate that G is 5 times greater at Jupiter, you must adjust the mass by 5 or else you can't explain the orbits of Jovian satellites. Once you adjust both (such that G*M remains constant) then calculations of weight, orbits, etc, give the same results in your theory as they do ours. You seem to be fooling yourself that the results are different at some level (such as at very near the surface of Titan), but in reality the results are the same.

If the results ARE different, I'm eager for you to show me how. But given your reluctance to perform simple math for us, I think I'll be waiting a long time.

I'm cutting it down some more, so focus on this part:

".. for each molecule 5 times the gravitational force, so it would take 1/5 th as many molecules.."

The catch word is "molecules", which is more than what you refer to in yours. "Each molecule" has greater gravitational mass. Yes, the weight results are the same, but for "fewer molecules" on Jupiter than Earth. All the other stuff on math etc, is superfluous if you can't get this one point, and no amount of math would make a lick of difference. :x

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Credibility is simply incredible... sometimes even to me.
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Wow... this was from page 2. I can't wait to catch up to this post of mine...

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Feynman
>~~~~<
Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.

Religion is a culture of faith; science is a culture of doubt.

This is wrong. Each molecule weighs more. Weight is a function of mass (and g). Mass is not a function of weight. This is intuitive, as the weight of objects can change, even in our real constant G universe, while their mass (by definition) remains the same.

Perhaps talking about Jupiter is overcomplicating the issue. Instead of assuming we got G wrong, what would happen to mass and weight if G were to suddenly change?

W = mg
W = m * (GM/R^2)

One day the flying spaghetti monster, ruler of the universe, suddenly changes G to 5G, leaving everything else the same. What do we expect would happen? The force of gravity becomes stronger throughout the universe. Orbits change. Everything becomes heavier.

Nothing happens to mass. Looking at the equations above, if G increases W increases, as we would expect. There is no reason or justification to change m or M.

Is this really "wrong"? Think about it. Isn't this the real issue, where you say "tomayto" and I say "tomahto"?

You say the molecules don't change, while I say there are fewer molecules for the same mass of one kilogram. In suddenly changing the G to 5G, you immediately assume that weight is changed. I say not. The weight is the same, but there are five times fewer molecules to account for it. This is where the math is deceiving, because in:

W = mg
W = m * (GM/R^2)

the change in G*M appears normal, though it should not be. If G is greater, then M is lesser, meaning "fewer molecules", and that changes everything. It's not that the whole universe went to 5G, but that specifically Jupiter resides in 5G, while we're in 1G. So it is not "overcomplicating the issue", but rather stating the issue as it is being presented, that G varies with distance from the Sun, hypothetically.

There is a very simple way to resolve this, in my mind. Take a piece of matter one kilogram to Jupiter and weight it per its gravitational weight. It should weigh 5 times as much as here. If it does, then there's our answer to this whole conundrum. Or take a kilogram of mass from Jupiter and bring it here, and it should weigh 1/5 th of what we thought we had. This is the most direct way, forget reaction wheels, etc., to find out if G out there is really different from here. And if it's the same? Then you guys were right and I was way off, totally wrong!

If I'm wrong, nothing changes in cosmology, so we carry on as before. It also means Einstein had it right. But if I'm right, then we have to start thinking seriously of what it means to most of our astrophysical theory, and astronomy would be revolutionized by it.

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Credibility is simply incredible... sometimes even to me.
disclaimer

Why forget reaction wheels etc? Those are direct measurements whether you want to acknowledge them as such or not. You may want to forget the reaction wheels, but you can't ignore the impulse supplied by the rockets to put them in orbit around Jupiter and Saturn. The length of the rocket firings to put those probes in orbit where calculated on the mass of the probes based on Earth G. If it is 5G at Jupiter, length of those firings would have been too short and the probes would never had made it into orbit. If you want to argue that the smaller mass at Jupiter allowed them to get into orbit, then you have to explain where 4/5 of the molecules went and also why the probes are still working when missing 4/5 of their molecules.

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Some try to tell me, thoughts they cannot defend,... - Moody Blues.

Our probes out there have not changed their inertial mass (tested with non-gravitational forces and through the moment of inertia), and it is clear they have not lost 4/5th of their molecules (otherwise they would not work).
Since they move and work as planned, your hypothesis fails the experimental test.

You have only vague hand-waving based on misunderstandings of gravity and dynamics, and misconceptions about wieght and mass.
If you propose a scientific hypothesis, you are supposed to provide some quantitative estimates.
That "other stuff on math" is what allows scientists to tell correct theories from incorrect ones.

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papageno


"Why waste time learning, when ignorance is instantaneous?" - Hobbes (Calvin and Hobbes)

"It's all about context!" - Vince Noir (The Mighty Boosh)

"I've never heard of such a brutal and shocking injustice that I cared so little about!" - Zapp Brannigan (Futurama)

No, you are simply wrong.

So, now you assume without any justification whatsoever that the amount of matter changes.
Do you realize that we can measure the amount of matter? (SI unit mole.)

Not then.
You can say "then M is lesser" only if you assume that W does not change.
And you can do that only if your hypothesis worked like this: "Let's assume that G is greater, but the weight does not change. Then we have to assume that M changes...", at which point you have to justify why M changes, and not m, since the formulae are symmetric for the masses:
W = M*(Gm/R^2).

And now you even change the amount of matter, without justification.
Why don't you consider non-material objects, such as photons?

And you keep coming up with ad hoc assumptions, that are incompatible with well-established observations.

Introducing assumptions without any justification is complicating the issue.

ANd we explained what would happen, hypothetically.

Have you forgotten that we have probes in the outer Solar System?
Do you think that an increase in gravitational mass wouldn't have been notice in "sling-shots" and orbits?

We gave reference that answered the questions.
You chose to ignore them.

Let's not forget them, because they are valid methods to test your hyptothesis, whether you like it or not.

We already have shown that you are wrong.
But you cannot accept it.

You are wrong, and research goes on without you.

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papageno


"Why waste time learning, when ignorance is instantaneous?" - Hobbes (Calvin and Hobbes)

"It's all about context!" - Vince Noir (The Mighty Boosh)

"I've never heard of such a brutal and shocking injustice that I cared so little about!" - Zapp Brannigan (Futurama)

Trust me, I'm jiggy wit your theory. The product G*M remains the same. So a 5X increase in G means a corresponding 5X decrease in M.

sorry dude -- physics IS math, and no amount of essay on your part changes that. If you can't do math, your theory ain't worth the ones and zero's it's posted with.

Pardon me? Weight wouldn't change? What exactly would be the observable change if G suddenly changed?

So are you saying that if we woke up one day and G here on Earth were 5 times greater, we would find the platinum and iridium bar (the very definition of 1 kilogram) in France would weigh the same because it magically lost molecules? Is this what you are saying?

Math is never deceiving.

So the Earth lost molecules? Where did they go?

We're dealing with another, simpler example now. I'm sorry that you don't like the one I brought up, but you have to deal with it.

I'm sure you'd like to, but