The discussion revolves around the potential effects of temperature, specifically near absolute zero, on the gravitational force as measured in experiments like the Cavendish experiment. Participants explore whether the gravitational constant (G) remains stable or could vary at such low temperatures, and they consider the implications of using cryogenic techniques in these measurements.
Participants do not reach a consensus on whether gravity changes at near absolute zero, and multiple competing views remain regarding the implications of cryogenic measurements on the gravitational constant.
Participants note limitations in current understanding and measurement techniques, including the dependence on temperature sensitivity of materials and the unresolved nature of how cryogenics might fundamentally alter gravitational measurements.
qaqtos said:Someone repeated the Cavendish experiment at about 0 K?
My question: the gravity force is costant when mass is near 0 Kelvin?
It is possible a weakening of G, a 'transition phase'?
The UCI Gravity Lab uses torsion pendulums operating at cryogenic temperature to perform tests of Newtonian gravity, the equivalence principle, and searches for new forces.
qaqtos said:I'm not speaking about distances but about temperature.
I contacted several physicists, MAGIA group also, but no answer.
My point: to repeat the Cavendish experiment (torsion balance) to measure the force of gravity between masses at temperature near 0 K or less than 2,7 Kelvin at least.
Instead of solid metallic spheres to put containers filled of liquid helium.
To be more precise: the mass has a gravity force of attraction stable or variable referring to the temperature?
I searched around the net but I find out nothing about this, there are gravimeters using masses of superconductor but they operate at temperature far above 0 K.
Any experiment is burdened with plant (or process) noise and measurement noise. Cryogenics should reduce both. Process noise in this case includes thermal vibrations in the torsion bar. Riley is also using cryogenics to reduce friction. I don't know how he is accomplishing this through the use of cryogenics and I don't know why this cannot be accomplished by some other means.ZapperZ said:The use of cryogenics would only eliminate thermal noise from the measurement.
D H said:The stated goal of Riley's group is 2 parts per million, or close to two orders of magnitude improvement.
qaqtos said:In the Riley's apparatus the balance torsion operate at criogenic temperature but the copper masses are not at crio temperature.
In yours opinions it is possible to carry out the G measurement with copper masses at crio temperature or sobstitute the copper masses with an He masses at crio temperature?
In other words: mass has the same G force at near 0 K?
Google search results: Your search - Podkletnov site:physics.uci.edu - did not match any documents.ZapperZ said:And this better not have any hint of the Podkletnov effect.
Boynton et al said:This ‘‘frequency method’’ was commonly used in the 20th century for measurements of the gravitational constant G, but with milliradian oscillation amplitude. We
operate at a much larger amplitude, near the value that yields a maximum in signal-to-noise ratio (Boynton, 2000). A downside to the frequency method has been the temperature sensitivity of a torsion fiber’s elastic modulus. Variation in fiber temperature will produce systematic and random errors in the frequency measurement. An effective remedy is to operate the pendulum in a cryogenic environment, providing reduced temperature sensitivity and an opportunity for improved temperature control.