1. 2009

    Failure of the equivalence principle?

    Here’s an interesting physics tidbit, to close out a long break from the science on this site: a couple of scientists claim to have proposed an experiment which theoretically should be able to distinguish between gravitational and inertial accelerations. This would break one of the most widely accepted laws of physics, the equivalence principle of gravitational and inertial masses — in other words, the belief that the \(m\) in \(F=ma\) is the same as the one in \(F=-GMm/r^2\) is now being challenged.

    But I’m not really buying it. The equivalence principle is one of those things that just makes sense, that’s why it’s been accepted so widely for so long. If it’s going to be overthrown, I need to see hard evidence, and nobody’s even done this experiment yet. I’m not familiar with the calculations they did that predict different responses for gravity and kinetic acceleration, but it’s easy to imagine that they might have missed a term somewhere, or perhaps one of the equations they used is incomplete, or whatever, and that would make physics a lot more consistent (albeit a lot less exciting) than the alternative of …