Not all stars are good parents to their budding planets — some get downright nasty and kick their children into interstellar space. We’ve found a handful of these free orphaned planets before, and they're called “rogue planets.” But a study today in Nature Astronomy suggests that the type we’ve seen so far, which are all gas giant sized, are the exception, not the norm.
“Basically, it is much easier to eject an Earth-mass planet than a Jupiter-mass planet,” Przemek Mróz, lead author of the paper and a PhD candidate at the University of Warsaw, says.
Research at the Warsaw University Observatory used data from the Optical Gravitational Lensing Experiment (OGLE) to search out these planets. Because they have no light of their own, they have to be found through gravitational lensing, which occurs when a large object bends space around it and acts like a giant magnifying lens, bringing out ...
