\n Artist\u2019s impression of the free-floating planet lensing light from a distant source<\/p>\n J. Skowron\/OGLE<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n Nearly 10,000 light years away, a planet the size of Saturn is floating all on its own through empty space. In a stroke of luck, researchers were able to spot this strange, dark world using both ground-based telescopes and the Gaia space telescope, allowing them to measure the mass of a free-floating, or rogue, exoplanet for the first time.<\/p>\n Most rogue worlds that have been found are either more massive than Jupiter or lighter than Neptune, leaving in the middle a gap in size that researchers refer to as the \u201cEinstein desert\u201d. This has generally been attributed to the idea that lighter-than-Neptune worlds are relatively easy to eject from pre-existing orbits around stars, whereas planets more massive than Jupiter don\u2019t have to form inside traditional planetary systems, but can sometimes form similarly to stars in free space.<\/p>\n That makes this newfound planet particularly rare. It has two names \u2013 KMT-2024-BLG-0792 and OGLE-2024-BLG-0516 \u2013 because Andrzej Udalski at the University of Warsaw in Poland and his colleagues spotted it independently with two different ground-based telescopes. But what\u2019s even more unusual is the fact that they were able to measure its mass at about one-fifth that of Jupiter.<\/p>\n \u201cWhat\u2019s really great about this one is that it\u2019s the first one that we\u2019ve got that has a mass measurement, and that was only possible because they got Gaia observations as well as Earth-based observations,\u201d says Gavin Coleman at Queen Mary University of London. The researchers found this planet through a method called gravitational microlensing, which occurs when the light from a bright, distant object is bent by a planet\u2019s gravitational pull, creating a sort of halo around the planet. That\u2019s where the researchers got lucky: when the microlensing event was spotted from the ground, the Gaia space telescope happened to be pointed in the right direction, so it captured the event too.<\/p>\n <\/p>\n \u201cMass is the main parameter deciding on the classification as a planet,\u201d says Udalski, so that makes this technically the first confirmed free-floating rogue planet. \u201cThis is the moment from which we may be sure that the candidate is a real planet, and free-floating planets indeed exist,\u201d he says. NASA\u2019s Nancy Grace Roman space telescope, planned to launch in 2027, is expected to find many more, though.<\/p>\n \u201cThey should be very numerous and they may be crucial for our understanding of the processes during the formation of planetary systems, as the majority of them are ejected from planetary systems at the early formation stages,\u201d says Udalski. That includes our own solar system, which some research hints may have ejected a planet in its early days.<\/p>\n <\/p>\n Experience the astronomical highlights of Chile. Visit some of the world\u2019s most technologically advanced observatories and stargaze beneath some of the clearest skies on earth.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n![\"New](\"https:\/\/images.newscientist.com\/wp-content\/uploads\/2024\/11\/28003449\/shutterstock_1102540808-scaled.jpg\")
\n <\/picture>\nThe world capital of astronomy: Chile<\/h3>\n