Man, deep space is weird. Remember the Pioneer 10 and 11 probes? They were sent off over 30 years ago, and now they’re well on their way out of the solar system. There’s just one problem: They seem to be in the grip of a mysterious force that’s holding them back. As The Guardian notes, a couple of researchers have found some unexplainable data:

By the time the two spaceships had swept beyond Pluto, they noted there were persistent anomalies in their trajectories. Every time they looked the Pioneers were in the wrong place. The effect was not large, but it was significant. Something more than the Sun’s gravity appeared to have a grip on the craft.

So now the hunt is on for a theory that can explain it. Inaccuracies in our understanding of gravity? Dark matter? Tractor beams from massive alien ships? Okay, that last one’s not really on the table, but many astronomers are now arguing that the only way to figure this out is to send out some more probes to the deepest parts of space, with instruments of higher accuracy. Of course, that’ll take another 30 years, which means I can look forward to perusing the new data from the rocking chair in my home for the elderly. I can’t wait.

(Thanks to Slashdot for this one!)