Last week I wrote about the Pioneer effect, an unexplained acceleration we’ve spotted in many of our far-traveling spacecraft. The Economist has a good article on it, and the additional details it reveals are fascinating. A team at JPL has put together a simple equation (unfortunately not in the article) that solves for the discrepant acceleration. It’s just that there’s no known force in physics that could be causing it. So here we have a mathematically predictable, yet unexplained, effect! This is huge! This is how many new laws of physics have come to us in the past.
The Economist also notes that the discrepancy isn’t observed in objects traveling in elliptical orbits (which is basically everything in the solar system except our space probes). There’s something about the hyperbolic orbits our space probes are in that exposes them to additional unexplained accelerations. There’s a huge mystery just waiting to be unraveled here, and I’m hopeful that when it is, we will emerge having learned a new fundamental truth of the universe.