Alien planet ‘aurorae’ may send signals towards Earth
Four brand-new alien planets have potentially been discovered after scientists detected the shimmering radio flashes of aurorae in those planets’ atmospheres. Aurorae occur when the solar wind, intense gusts of electric particles belched out by the Sun, smash into a planet’s magnetic shield. Earth experiences aurorae near the north and south poles, where miraculous displays of colour and light streak through the sky. But this pleasant light show is only a piece of the story; astronomers know that the cosmic clash of the solar wind and magnetic fields also produces bright flashes of radio light that can be seen far across the galaxy. To an alien observer hundreds of light years away, the aurorae of Earth may look like sudden, bright explosions of radio energy.
Scientists think they’ve discovered four planets within 160 light years of Earth by detecting the shimmering radio flashes of aurorae in those planets’ atmospheres. If confirmed by future research, these four alien worlds will be the first planets detected through radio waves, potentially opening a new avenue for planetary detection in our galaxy. “It’s a spectacle that has attracted our attention from light years away,” said Joseph Callingham, an astrophysicist at Leiden University in the Netherlands.
The researchers discovered these potential planets somewhat accidentally while surveying nearby red dwarf stars with the
Low Frequency Array (LOFAR) radio telescope in the Netherlands. Red dwarfs are much smaller, cooler stars than our Sun and are thought to be the most common type of star in the galaxy. These stars typically have very large magnetic fields, and tend to flare up with gigantic bursts of energy that are visible across the electromagnetic spectrum.
Of the 19 red dwarfs the researchers detected, four seemed a little unusual. These oddball stars appeared very old and magnetically inactive, yet they still shined with bright radio signals. If these signals weren’t the result of large magnetic flare-ups, then what could be causing them? Using a mathematical model, the team concluded that the strange radio signals are most likely from a powerful auroral process occurring in the atmospheres of unseen, undiscovered planets orbiting the old stars. The process is similar to aurorae on Earth, with charged solar wind clashing with a magnetic field, but they may behave more like the powerful aurorae seen on Jupiter.
“Aurorae from Jupiter [are] much stronger, as its volcanic moon Io is blasting material out into space, filling Jupiter’s environment with particles that drive unusually powerful aurorae,” Callingham said. “Our model for this radio emission from our stars is a scaled-up version of Jupiter and Io.” With radio data alone, the researchers can’t be sure that hidden planets are responsible for the strange signals around these old stars. However, powerful planetary aurorae seem to be the most plausible explanation right now.
Further observations of the withered stars could reveal if the team’s theory is correct, and whether bright blasts of radio energy can help lead astronomers to more alien worlds in the future.