---
author: Eric Wagoner
date: '2001-05-16T03:47:00'
draft: false
title: Mystery Force
---

As our probes are sailing across (and out of) the solar system, they're slowing down faster than they ought to. [Perhaps we don't know all there is to know](http://news.bbc.co.uk/hi/english/sci/tech/newsid_1332000/1332368.stm) about gravity.