Astronomers have found the strongest evidence yet that planets beyond our solar system possess magnetic fields, solving a crucial query within the study of distant worlds.
Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) and the Gemini North telescope in Hawaii, researchers measured wind speeds on seven extremely hot, Jupiter-like exoplanets.
The findings suggest the winds are likely shaped by planetary magnetic fields, providing what scientists describe as the primary robust evidence of magnetism on planets outside the solar system.
Julia Seidel, lead writer of the study, said: ‘This breakthrough opens a totally latest window on exoplanet research.
‘It’s the primary time we will compare the magnetic environments of other worlds – a key step toward ultimately understanding which planets can stay alive, keep their water, and maybe even, someday, host life as we understand it.’
Magnetic fields are known to play a vital role in shaping planetary atmospheres.
Join for all of the newest stories
Start your day informed with Metro’s News Updates newsletter or get Breaking News alerts the moment it happens.
Earth’s field helps protect the atmosphere and is taken into account essential to maintaining conditions suitable for all times. Other planets within the solar system, including Jupiter and Saturn, also possess strong magnetic fields.
Nevertheless, despite years of study, direct measurements of magnetic field strength on exoplanets had not previously been achieved.
Researchers on this study, published in Nature Astronomy, didn’t initially got down to measure magnetism.
As an alternative, they focused on atmospheric winds across seven exoplanets orbiting distant stars.
These gas giants are similar in size to Jupiter but are tidally locked, meaning one side permanently faces their host star.
This creates hot temperature differences between a scorching day side and a freezing night side, driving powerful atmospheric winds.
Wind speeds within the sample ranged from around 7,200 km/h (4,500mph)to greater than 25,000 km/h (15,500,ph) By comparison, Jupiter’s fastest winds reach roughly 1,500 km/h (930mph).
‘At first we set out to ascertain if the atmospheric winds behaved the identical way for all hot planets,” said Seidel, who’s an astronomer on the Laboratoire Lagrange, Observatoire de la Côte d’Azur, France.
The team used data from the ESPRESSO instrument on ESO’s VLT in Chile’s Atacama Desert, alongside an identical instrument on Gemini North, a part of the International Gemini Observatory.
Nevertheless, when the researchers compared wind speeds with planetary temperature, they observed an unexpected pattern: hotter planets tended to have slower winds.
‘This is completely counter intuitive because, all things being equal, hot planets have more energy to speed up the winds. Something must occur that slows down the wind speeds for warmer objects,’ study co-author Vivien Parmentier said.
Probably the most plausible explanation, the team concluded, is the presence of worldwide magnetic fields.
These fields can act as a drag on atmospheric motion by slowing charged particles, effectively braking the winds.
This allowed researchers to estimate the strength of the magnetic fields on each planet, which they found to be comparable to those inside our own Solar System – around 4 times the strength of Saturn’s field or roughly half that of Jupiter’s.
Such magnetic fields could influence greater than just atmospheric circulation. On Earth, magnetic interactions between solar particles and the atmosphere produce auroras within the polar regions.
‘Here on Earth, we all know the fantastic thing about the northern and southern lights, where particles from the Sun hit our magnetic field and are guided toward the poles, colliding with gases within the atmosphere to provide vibrant displays of green, pink, and purple,’ study co-author Bibiana Prinoth said.
On these distant exoplanets, scientists imagine similar – and potentially much more intense – auroras could occur.
Future observations with ESO’s Extremely Large Telescope are expected to assist researchers study not only gas giants but additionally smaller, Earth-like planets, and potentially detect atmospheric signatures linked to auroral activity.
Prinoth said: ‘I prefer to imagine that a few of these worlds have a sky filled not only with stars, but with vast curtains of vibrant light dancing across a planet that’s half in perpetual day and half in limitless night.’
MORE: Jeff Bezos’s Blue Origin rocket explodes into giant fireball during test
MORE: Elon Musk’s megarocket ‘could offer 34-minute flights between London and Hong Kong’
MORE: Climber wrote online she ‘felt uncertain’ before falling 2,000 ft down volcano