OCT 15, 2007 - Pioneer Anomaly is for you, if you love a cosmic mystery. This mystery is most peculiar, and most definitely cosmic. It's happening in the outer reaches of our solar system, where NASA's Pioneer 10 and 11 spacecraft are apparently being held up on their way out of our system. Each year, they're falling some 5,000 kilometers behind in their projected course. The spacecraft were launched in 1972 and 1973, and the discrepancy in their progress has been known since 1980. What isn't known is the cause. It may be some engineering artefact, or the effect of interstellar wind or some unknown body in the outer solar system. At the outside edges of the realm of probability, the cause might even be some hitherto unknown force that would revolutionize physics. The Planetary Society is attempting to analyze the Pioneer data, and you can help.
