# What are the most precise (hence recent) tests of the inverse square law for gravity?

Hi guys,

I know that in a 2001 paper there were tests of the inverse square law for gravity down to 218\mu metres. But i have seen in other papers (more recent ones) that they claim it has been tested to a greater precision, somewhere around 100\mu metres i think. But these papers only make reference to this accuracy but give no actual references and don't know how i could find a paper which describes this precise test.

Does anyone know of any papers that have tested gravity to a finer precision? Is much appreciated.

Karnten07

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First, you're confusing two different things. The precision of a test is how small a deviation you could see: for example, a test that could spot a 1% variation is twice as precise as one that could spot a 2% variation. The length scale at which gravity is what is measured in microns. But you can have a more precise test at a longer distance, for example.

Second, I don't know what the measurement at the smallest length scale is, but I expect if you look for Eric Adelberger's publications (he's at the University of Washington), it would be a good start.

First, you're confusing two different things. The precision of a test is how small a deviation you could see: for example, a test that could spot a 1% variation is twice as precise as one that could spot a 2% variation. The length scale at which gravity is what is measured in microns. But you can have a more precise test at a longer distance, for example.

Second, I don't know what the measurement at the smallest length scale is, but I expect if you look for Eric Adelberger's publications (he's at the University of Washington), it would be a good start.
Ah yes, you're right, sorry for the confusion. I was looking for the tests of gravity at the smallest length scale. Eric's paper is the one that i have and it is dated 2001, so i wasn't sure if these were the smallest length scales studied to date.

Ah, i found something, Eric is going to review recent tests on the inverse square law of gravitation down to 85\mu metres, now i just need to find the paper he's talking about! anyone? Thanks for your help Vanadium

Karnten07

Ah yes, you're right, sorry for the confusion. I was looking for the tests of gravity at the smallest length scale. Eric's paper is the one that i have and it is dated 2001, so i wasn't sure if these were the smallest length scales studied to date.

Ah, i found something, Eric is going to review recent tests on the inverse square law of gravitation down to 85\mu metres, now i just need to find the paper he's talking about! anyone? Thanks for your help Vanadium

Karnten07
Its okay i found it, gravitation has been tested down to 56\mu metres and te inverse square law still holds.