Newton’s constant, which describes the strength of the gravitational pull that bodies exert on each other, is the most poorly determined of the constants of nature. The two most accurate measurements have experimental errors of 1 part in 10,000, yet their values differ by 10 times that amount. So physicists are left with no idea of its absolute value.

Now Jean-Paul Mbelek and Marc Lachieze-Ray of the French Atomic Energy Commission near Paris say they can resolve the contradiction by taking into account the location of the labs where the experiments were carried out.

The pair suggest that electromagnetism and gravity influence one another enough for gravity’s pull to be noticeably affected by the Earth’s magnetic field.