# Random Samples

Science  16 Jun 2006:
Vol. 312, Issue 5780, pp. 1579
1. # SOLVING THE PIONEER ANOMALY

A new effort has been launched to explain the mysterious slowdown of two NASA spacecraft. Pioneer 10 and 11 left Earth more than 30 years ago to explore the outer solar system, and over the past 11 years, Doppler radar data have shown that they are slowing down slightly more than would be expected from the sun's gravity alone. Right now, as the pair approach the edge of the solar system, the two spacecraft are almost 400,000 kilometers closer to the sun than scientists predicted.