The far side of the Moon stays permanently turned away from Earth due to tidal locking, creating a hemisphere shaped by a thicker crust, heavier cratering, and an absence of vast volcanic basalt plains. While the near side features smooth maria that once led early astronomers to suspect lunar seas, the opposite hemisphere is rugged, mountainous, and geologically distinct.
Space agencies spent decades trying to map and understand this hidden hemisphere. Today, orbiters, landers, and rovers provide clear data on why the two sides of the Moon look so drastically different and what they tell us about the early solar system.
Why We Never See the Far Side from Earth
Tidal locking is the gravitational interaction responsible for keeping the same lunar face pointed toward Earth. As the Moon rotates on its axis once, it simultaneously completes one full orbit around Earth, taking roughly 27.3 days for both movements.
This synchronization isn't an accident. Over billions of years, Earth's gravitational pull raised tidal bulges on the Moon, acting as a brake on its rotation until the spin rate matched the orbital period.
Because of this celestial mechanics, only about 59 percent of the lunar surface is visible from Earth over the course of a full wobble cycle, known as libration. The remaining 41 percent remained completely unseen by human eyes until the Soviet Luna 3 probe swung behind the Moon in 1959 and transmitted the first grainy images of the far side back to ground stations.
Crustal Thickness and the Great Asymmetry
The most striking difference between the two lunar hemispheres is the distribution of maria. On the near side, dark basaltic plains cover roughly 31 percent of the surface. On the far side, those same plains cover less than two percent.
Scientists long debated why the hemispheres look so asymmetrical, and planetary researchers now trace the cause back to crustal thickness. Data gathered by NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission revealed that the far side crust is about 12 miles thicker than the near side crust.
During the Moon's early volcanic period, molten magma struggled to punch through the thick, rugged crust of the far side. On the near side, a thinner crust combined with higher concentrations of heat-producing radioactive elements allowed vast floods of lava to reach the surface and fill impact basins, creating the smooth dark patches we see today.
Key Landmarks and Impact Basins
The far side is home to some of the most monumental impact features in the solar system, preserved because volcanic activity didn't flood and erase them.
The South Pole-Aitken basin is the crown jewel of lunar geology. Spanning roughly 1,550 miles in diameter and reaching depths of up to 5 miles, it ranks as one of the largest confirmed impact craters in the solar system. An ancient asteroid impact carved out this colossal depression, excavating material deep from the lunar mantle and offering geologists a natural drill core into the Moon's interior.
Another notable feature is the Korolev crater, a 110-mile-wide depression near the northern pole that famously traps thick sheets of water ice in its permanently shadowed floor.
Historic and Modern Far Side Missions
Exploring the far side presents a major engineering hurdle: direct radio communication with Earth is impossible because the bulk of the Moon blocks all signals. Overcoming this barrier required placing specialized relay satellites in halo orbits beyond the Moon.
In 2019, China's Chang'e 4 mission achieved the first-ever soft landing on the far side inside the Von Kármán crater. The mission relied on the Queqiao relay satellite, positioned at the Earth-Moon L2 Lagrangian point, to maintain continuous contact. The mission deployed the Yutu-2 rover, which has spent years analyzing local regolith, measuring subsurface thermal profiles, and discovering mantle rocks cast up by ancient impacts.
NASA's Lunar Reconnaissance Orbiter (LRO) has also mapped the terrain in extreme detail, providing high-resolution imagery that helps researchers chart landing sites and study impact mechanics.
Future Exploration and Radio Astronomy
Beyond geology, the far side offers a unique advantage for science: it is the quietest radio location in the inner solar system.
Because the Moon blocks all human-made radio chatter, television broadcasts, and military radar originating from Earth, the far side is an ideal spot for low-frequency radio astronomy. Placing radio telescopes inside far side craters would allow scientists to peer back into the cosmic dawn—the era before the first stars ignited—without interference from Earth's noisy ionosphere.
Space agencies and private aerospace firms are actively planning robotic and crewed outposts on the Moon. While near-side locations offer easier communication, the scientific value of the far side makes it a prime target for future lunar bases.
Frequently Asked Questions
Is the far side of the Moon the same thing as the dark side?
No. Every part of the Moon receives sunlight over the course of a 29.5-day lunar cycle, including the far side. The term "dark side" historically referred to its unknown, unexplored nature rather than a lack of sunlight.
Why are there fewer dark plains on the far side?
The crust on the far side is significantly thicker than on the near side. Ancient volcanic magma could not easily break through the thicker crust to form the basaltic plains known as maria.
How do spacecraft communicate from the far side of the Moon?
Spacecraft must use a relay satellite positioned in a halo orbit around the Earth-Moon L2 Lagrange point. This satellite maintains a direct line of sight to both the far side lander and ground stations on Earth.
Can you see the far side of the Moon with a backyard telescope?
No. Because of tidal locking, the far side is permanently turned away from Earth. Even with libration wobbles, no Earth-based observer can ever view the far side directly.
