Mysterious chorus waves Researchers discover cosmic chirping far from Earth

For the first time, researchers have registered chorus waves far away from Earth - where they were not expected. The discovery raises a lot of questions.

Scientists have detected sounding cosmic waves at a greater distance from the Earth than ever before. The so-called chorus waves were picked up by four satellites launched in 2015 to study the magnetic fields of the Earth and the Sun, according to an article published in the journal Nature on Wednesday. Chorus waves have also been registered before, but never at a distance of more than 100,000 kilometers as now.

Chorus waves are probably caused by an interaction between solar winds and the magnetic field of planets. When they are converted into audio signals, they sound like high-pitched bird calls. Radio antennas picked them up decades ago, including at a research station in Antarctica in the 1960s. And two US space probes heard the chirping from the Earth's radiation belt at a shorter distance than the discovery now published.

The chorus waves now discovered were found in a region where the Earth's magnetic field is stretched, which scientists had not expected. "This raises a lot of new questions about the physics that might be possible in this area," said space physicist Allison Jaynes of the University of Iowa, who was not involved in the work. "It's very compelling, very compelling," Jaynes said. "We definitely need to find more processes like this."

Chorus waves have also been detected near other planets, including Jupiter and Saturn. They can generate high-energy electrons capable of disrupting satellite communications. "They are one of the strongest and most significant waves in space," wrote study author Chengming Liu from Beihang University in an email.