At the University of Oklahoma, astrophysicists have discovered exoplanets in another galaxy for the first time. Professor Xinyu Dai and postdoctoral researcher Eduardo Guerras used a technique called microlensing to find these planets, which reside in a galaxy 3.8 billion light years away. Microlensing uses the warping of space created by a massive body to turn spacetime into a lens, projecting multiple images of another object behind it that may now be magnified and brighter. These objects can be two stars lined up with each other, or a quasar and another galaxy. In this case, Dai and Guerras observed a quasar whose light bent around a galaxy in front of it to study emissions from the quasar’s supermassive black hole. Finding strange changes in these emissions, the astronomers determined that there must be a large population of rogue planets, ranging in size from the Moon to Jupiter, drifting free of stars in the lensing galaxy.
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