Astronomers detect first radio signal directly from a planet outside our solar system

Astronomers say they have detected radio waves coming directly from a planet outside our solar system for the first time, potentially opening up a new way to study distant worlds. The signal comes from Beta Pictoris b, a giant exoplanet about 63 light-years from Earth. The planet is roughly 12 times the mass of Jupiter and orbits a young star known as Beta Pictoris. Despite the inevitable association between radio signals and searches for extraterrestrial intelligence, researchers say there is no suggestion that aliens are responsible, CNN reported. Instead, the radio waves appear to be produced by the planet's extraordinarily powerful magnetic field and auroras. The research has been posted as a preprint and has not yet undergone peer review, so independent scientists are urging caution until the findings have been formally assessed. A magnetic field far stronger than Jupiter's The radio signal appears to be associated with auroras, phenomena similar to Earth's northern and southern lights. Auroras occur when charged particles interact with a planet's magnetic field. These energetic particles can also produce radio waves. Researchers estimate that Beta Pictoris b's magnetic field is at least 200 times stronger than Jupiter's. That is particularly striking because Jupiter already has an enormous magnetosphere, extending millions of kilometres towards the Sun. Astronomers have previously detected this type of auroral radio emission from Jupiter and Saturn, as well as the Sun, stars and brown dwarfs. The signal from Beta Pictoris b would be the first time such an emission has been directly detected from an exoplanet. Why is the discovery important? Magnetic fields can tell scientists a great deal about planets. Earth's magnetic field, for example, acts as a protective shield, helping prevent the solar wind from stripping away the atmosphere. Studying magnetic fields around exoplanets could therefore help astronomers understand their internal structure, atmospheres and interaction with their host stars. Until now, astronomers had seen possible signs of radio emissions associated with exoplanets, but it was difficult to prove whether the signals came from the planets themselves or from their host stars. That is what makes the new detection unusual. Joseph Callingham of the University of Amsterdam, who was not involved in the research, said the study was able to locate the radio emission at the planet itself and distinguish it from the star. How did astronomers find the signal? Researchers detected the radio waves using MeerKAT, a network of 64 radio telescope dishes in South Africa. The discovery was unexpected. The researchers had assumed that if exoplanets possessed magnetic fields similar to Jupiter's, their radio emissions would occur at frequencies lower than those detected by MeerKAT. Instead, the team found repeating radio bursts at frequencies suggesting a much more powerful magnetic field. The researchers initially considered whether the signal could actually be coming from the star. But they said repeated observations at several frequencies allowed them to pinpoint Beta Pictoris b as its source. A very young planetary system Beta Pictoris is already one of the most closely studied planetary systems. At around 23 million years old, it is extremely young compared with our 4.5-billion-year-old solar system. Beta Pictoris b was discovered in 2008, while two other planets in the system, Beta Pictoris c and Beta Pictoris d, were discovered in 2019 and 2026 respectively. The star is also surrounded by a huge disk of dust and debris left over from planet formation and is known to host around 30 orbiting comets. Scientists want more observations Researchers are now seeking additional telescope time to study Beta Pictoris b and understand why its magnetic field appears to be so powerful. Scientists who were not involved in the research say confirmation through peer review will be important. If the findings hold up, they could show that planets outside our solar system are capable of generating magnetic fields far stronger than astronomers previously expected. More importantly, the discovery suggests that radio astronomy could give scientists an entirely new way of investigating exoplanets, revealing characteristics that are difficult or impossible to measure using conventional telescopes.