Lunar swirls

Lunar swirls are mysterious bright marks on the surface of the Moon. They stand out because they are very bright, looking as if they are made from fresh, young material, even though they may be very old. These swirls often twist and turn in winding paths, and they sometimes have darker areas that flow between the bright parts.

These swirls can be found on different parts of the Moon, both on the dark, smooth areas called lunar maria and on the lighter, bumpy highlands. On the maria, the swirls are very noticeable with strong bright and dark contrasts and complex shapes. In the highlands, they are usually simpler, sometimes looking like single loops or small bright spots.

Scientists find lunar swirls fascinating because they do not change the shape of the Moon’s surface, even though they cover craters and other features. Understanding these swirls helps us learn more about how the Moon’s surface has changed over time and what forces have shaped it.

Association with magnetic anomalies

Lunar swirls are linked to areas on the Moon where there are strong magnetic fields. The Moon does not have its own active magnetic field like Earth, so these areas are thought to be remnants of magnetism from the past. Space missions such as Apollo 15, Lunar Prospector, and Kaguya have mapped these magnetic fields from orbit. Not every magnetic anomaly on the Moon has a visible swirl, but every swirl is connected to a magnetic anomaly. Scientists are still studying where these magnetic fields come from.

Formation models

Scientists have three main ideas about how lunar swirls formed. All these ideas try to explain two special features of swirls: they look very bright and young, and they are linked to areas with unusual magnetic fields on the Moon.

One idea is that a comet hitting the Moon could create swirls. This impact might stir up the surface and leave behind fresh, bright material. Another idea is that the Moon’s magnetic fields protect certain areas from the solar wind, keeping these spots brighter over time. A third idea suggests that electric fields move tiny dust particles, causing bright material to gather in swirl shapes. Each model offers unique clues about these mysterious lunar features.

Main article: Lunar swirls

Satellite measurements

Scientists have studied lunar swirls using special tools on spacecraft like Clementine and Lunar Prospector. These tools measure magnetic fields and have found clues that suggest solar wind—the stream of particles from the Sun—is being blocked by invisible magnetic fields around the swirls.

More recent tools, such as those on the Lunar Reconnaissance Orbiter and the Moon Mineralogy Mapper on Chandrayaan-1, also support this idea. As of 2018, scientists at NASA are planning a new mission called Bi-sat Observations of the Lunar Atmosphere above Swirls or BOLAS, using two tiny satellites connected by a long cable to learn more about how these mysterious swirls formed.

Onsite investigations

NASA plans to send a rover to Reiner Gamma to study the surface materials there. The Lunar Vertex mission, managed by the JHU Applied Physics Laboratory, was chosen for flight through the PRISM proposal process. The rover will be delivered as part of the CLPS CP-11 task order, which Intuitive Machines will handle during the IM-3 mission. A MAPP rover equipped with a multispectral microscope will examine the texture and brightness of surface particles and send its findings to the lander for communication with Earth.