Published On 4/6/2026
An international team of astronomers achieved an unprecedented achievement after being able for the first time to measure the magnetic fields of seven exoplanets located outside the solar system. This discovery is an important step towards understanding the conditions that make some planets able to maintain their atmospheres and perhaps support life in the future.
The importance of magnetic fields is that they act as a protective shield that protects planets from high-energy stellar radiation and particles. Earth’s magnetic field helped protect its atmosphere and water for billions of years, while Mars lost a large portion of its atmosphere after its magnetic field declined.
The results of the study were published in the journal Nature Astronomy, where researchers made this discovery while studying wind speeds in a group of hot giant planets, without searching for magnetic fields as their primary goal.
Read also
list of 2 itemsend of list
Slow winds reveal the magnetic secret
The researchers focused on seven “Ultra-Hot Jupiters” planets, which are giant gas planets that orbit very close to their stars. As a result, it became tidally restricted, with one side constantly facing the star while the other side remained immersed in perpetual darkness.
The temperatures of these planets reach about 2,300 degrees Celsius or more, which leads to the emergence of huge winds with speeds ranging between 7,200 and 25,000 kilometers per hour. For comparison, the wind speed on Jupiter does not exceed about 1,500 kilometers per hour.
Scientists relied on the ESPRESSO spectrometer at the European Giant Telescope in Chile, and the MAROON-X spectrometer at the Gemini North Telescope in Hawaii. These devices analyze the light coming from the planets into its different wavelengths, which allows studying the composition of the atmosphere and tracking the movement of elements within it, especially iron.
Slow winds reveal the magnetic secret
An artist’s drawing showing a “hot Jupiter” star with enormous winds blowing on it, affected by its magnetic field, which slows it down and reshapes its paths (Gemini International Observatory)
While analyzing the data, scientists noticed a surprise that confounded their theoretical expectations. Instead of wind speeds increasing with temperature, as required by simple physical laws, they found that hotter planets have slower winds.
Researcher Julia Seidel described this matter in an official press release as “completely contrary to scientific intuition,” because the additional energy is supposed to make the winds more violent. As for researcher Vivien Parmentier, he pointed out that there is an invisible factor that curbs these winds.
After ruling out other explanations, the team concluded that magnetic fields are the most likely cause of this, as these fields affect charged particles within the planet’s atmosphere, acting as a kind of “brake” that slows down the movement of winds and regulates the flow of energy between the two sides of the planet.
A new step towards the search for habitable worlds
The study showed that the strength of these magnetic fields is only several gauss (a physical unit that expresses the strength of the magnetic field), which is much less than some theoretical expectations that suggested the presence of fields hundreds of times stronger. However, their values remain similar to those found in some of the giant planets in our solar system.
Although the seven planets studied are not habitable because they are extremely hot gas giants, the importance of the discovery extends beyond these worlds themselves. The presence of a magnetic field is one of the essential elements that may help rocky planets retain water and protect their atmospheres from erosion by stellar winds.
Scientists believe that the new technology may become a major tool in the coming decades, especially with the entry of a new generation of giant telescopes into service. By measuring the magnetic fields of distant planets, researchers will be able to more accurately assess their chances of habitability, bringing humanity one step closer to answering one of the oldest scientific questions: Are we alone in the universe?
