Yes, this experiment needs to be confined to earth. Otherwise we won't be able to replicate it.
I don't trust NASA. Or any authority figures, really.
If gravity were actually magnetism, wouldn't non-ferrous objects float away?
I don't know how they phrased it, but "given a big enough magnet, everything can be magnetic" or something.
Of course that magnet would be earth sized.... probably not an experiment that can be done.
The best experiment would be to get two large masses - probably a beach ball sized lead ball - weighing a ton or so each. Not too big as to be unwieldy, but big enough to have some impact on each other.
Have one held in place by a large hanging wire on the top, and then also just barely kept off of center by a load cell, that measures force on it. Have the load cell hold the weight maybe 1 degree off vertical, pulling away from from the other mass.
The second mass have on a some sort of mechanism that can effect a sudden withdrawal from the first ball, something like a huge spring, say 10 meters long.
The experiment would be to measure the force on the first ball with the load cell as the second ball is moved in closer and closer.
If gravity were a thing, then the force would change as the second ball got closer. Suppose there was a reading change at the 5cm mark.
Now use the spring to retract the second mass essentially instantaneously away from the first mass, and watch the corresponding force on the first mass.
Given a big enough mass, with a fast enough withdrawal time, there should be some sort of effect on the two masses.
Doing the experiment in a vacuum would eliminate any effects of air currents, etc.
But yeah, gravity experiments inside earth's gravity are very hard.
Almost sounds like the Cavendish experiment.
If the moon pulls on the tides, does it pull on anything else?
Cavendish did a pendulum for constant mass interactions.
My experiment idea focuses on the difference of masses. The ideal experiment would be to teleport an object of large mass into a field. That sudden appearance of mass would create a new force on the object.
Think of teleporting the earth next to a space craft moving in a straight line. Or even just floating in space and then suddenly falling because earth appeared below you.
The spring retracts the second large mass a huge distance relative to the point where the force was measured, making it essentially "disappear", and the second mass would then feel a sudden (and hopefully strong) recoil effect because of the now missing mass.
The vacuum would try to make sure no air currents pushed on the first mass that would make it sway or whatever.
It pulls on everything else. We can't see air, otherwise we would most likely see small air tides up to 20 miles or so.
Nothing else has as much freedom to rearrange as liquids or gas. Dirt wants to move but can't.
I guess you could suspend a weight on a scale and measure the difference as the moon goes by.
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