Alien winds may reveal hidden truth about exoplanets' magnetic fields

Astronomers have spent decades listening for radio signals from hot giant planets in space, suspecting these alien worlds would have strong magnetic fields like Jupiter to produce them. Some theories have predicted distant exoplanets to have monster magnetic fields hundreds of times stronger than Earth's, so their absence has been baffling. But new findings suggest maybe the silence itself is the clue. Maybe those planets don't have enormous magnetic fields after all. For the first time, scientists have inferred the strength of magnetic fields around exoplanets, and they did so in a wholly unexpected way. The results may help astronomers better understand how smaller, potentially habitable worlds make and keep their own magnetic fields. "This breakthrough opens a completely new window on exoplanet research," said Julia Seidel, an astronomer at the Laboratoire Lagrange in France and lead author of the work, in a statement. "It's the first time we can compare the magnetic environments of other worlds — a key step toward ultimately understanding which planets can stay alive, keep their water, and perhaps even, one day, host life as we know it." The study, published in Nature Astronomy