Hot Side of the Moon

he close side of the moon, facing Earth, is dark and made up mainly of ancient lava flows, but the far side is rougher. The reason for the difference, according to studies by NASA scientists, lies in an irregular moon interior. Based on data from two spacecraft called Ebb and Flow, they found that the moon's mantle may deform differently on each side by a 2-3% margin. They believe the near side may be up to 170°C hotter than the far side. This discovery, in Nature, points to the likelihood that there are likely to be temperature variations deep inside the moon. The difference internally can contribute to why the near side and the far side are so different and have such different volcanic activity. The near side is darker due to having more lava flows, which represent more volcanic activity, while the far side is more mountainous.

Ryan Park and co-authors drew on NASA GRAIL mission data, which showed details of the internal structure of the moon by mapping the moon's gravity response as it orbits around Earth.

They found a 2-3% difference in how the mantle of the moon can be deformed between the two hemispheres. They mimicked the moon's structure and concluded that the temperature gradient of the mantle can be 100-200 Kelvin, most likely because of thorium and titanium radioactive decay on the near side. Techniques used here can also be used to investigate the interior of other objects like Mars and Ganymede without the need to land spacecraft.

Reference

Nature Publishing group.Twin spacecraft mission reveals there might be a 'hot' side of the moon. Phys.org. Available at- https://phys.org/news/2025-05-twin-spacecraft-mission-reveals-hot.html

(Assessed: 19th May 2025)