It's lonely out in space. But our Milky Way galaxy has long been thought to have a couple of trusty companions, the Small Magellanic Clouds. These two diminutive galaxies seemed to be forever bound to our own, hitchhiking through the cosmos for the ages. Now one measurement of their velocities has "thrown out everything we thought we understood about their history and evolution," a researcher said. Turns out the little parasites are just passing through.