I was sorry to learn that there is likely a very rational explanation for the Pioneer anomaly, the 30-year mysterious deceleration of the Pioneer spacecraft once it got out of the solar system, a mystery much loved by science fiction readers. I would have liked the mystery even better if there had been an unexplained acceleration, but you can’t have everything.
It seems that no singularities are involved after all, and that gravity doesn’t get stronger or weaker at long distances either. Heat ‘Most Likely Cause’ of Pioneer Anomaly:
A number of possible explanations have been proposed over the ensuing decades, including the possibility that gravity behaves differently at such large distances from earth — thereby requiring a modification of gravitational theory.
But over the last couple of years, evidence has been pointing more strongly to heat as the most likely culprit. Specifically, heat from the plutonium inside the spacecraft’s generators, some of which got converted into electricity while the rest of it radiated into space. If it did so unevenly, radiating more heat in one direction than in another — only a 5 percent difference is required — that might be sufficient to give rise to the Pioneer anomaly.
Found via Slashdot.