Fact Check | How the Moon got ‘sunburns’: A result of sheer magnetism

The Sun releases a continuous outflow of particles and radiation called the solar wind. Because the solar wind is magnetised, Earth’s natural magnetic field deflects the solar wind particles so that only a small fraction of them reach the planet’s atmosphere. But the Moon has no global magnetic field; magnetised rocks near the lunar surface do create small, localised spots of magnetic field.

“The magnetic fields in some regions are locally acting as this magnetic sunscreen,” NASA quoted researcher Andrew Poppe (University of California, Berkeley) as saying. Under these miniature magnetic umbrellas, the material that makes up the Moon’s surface, called regolith, is shielded from the Sun’s particles.

As those particles flow toward the Moon, they are deflected to the areas just around the magnetic bubbles, where chemical reactions with the regolith darken the surface.

This creates the distinctive swirls of darker and lighter material.

(Source: NASA)