What is on the other side of the Moon?

The Moon is Earth’s only natural satellite and the fifth largest moon in the solar system. The Moon has a diameter of about 2,160 miles (3,476 km), making it around one quarter the size of Earth. The Moon orbits Earth at an average distance of about 238,855 miles (384,400 km) and completes one orbit every 27.3 days.

What causes us to only see one side of the Moon from Earth?

The Moon rotates on its axis at the same rate that it orbits Earth, which results in the same side of the Moon always facing the Earth. This phenomenon is known as synchronous rotation or tidal locking. The Moon completes one rotation every 27.3 days, which is the same amount of time it takes to complete one orbit around Earth. This synchronous rotation causes the Moon to show only one face to Earth as it orbits.

This tidal locking occurred because of the gravitational forces between the early Moon and Earth after the giant impact event that formed the Moon. The part of the Moon that faces Earth is called the near side. The opposite side, which always faces away from Earth, is called the far side or dark side, even though it receives just as much sunlight as the near side.

What have we learned about the far side of the Moon?

Until the Space Age, very little was known about the far side of the Moon. It wasn’t until 1959 when the Soviet Luna 3 spacecraft returned the first images of the far side that we got our first glimpse. Since then, several NASA and international space missions have studied the lunar far side in more detail.

In 1968, NASA’s Lunar Orbiter 4 mapped almost the entire far side surface. Data from orbiters like Lunar Prospector, SMART-1, Kaguya, and Lunar Reconnaissance Orbiter have also been used to study the geology and topography of the far side. Most recently, China’s Chang’e 4 became the first spacecraft to successfully land on the lunar far side in 2019.

Thanks to these missions, we now know that the far side has a thicker, more cratered crust than the near side. Some key features of the far side include:

  • South Pole-Aitken Basin – This is one of the largest known impact craters in the solar system, measuring roughly 1,550 miles (2,500 km) across and 5.6 miles (9 km) deep.
  • Tsiolkovskiy crater – A large impact crater about 185 miles (300 km) in diameter and with a maximum depth of over 12,100 feet (3,700 meters).
  • Von Kármán crater – A crater around 115 miles (186 km) in diameter that contains one of the Moon’sHighest concentrations of the mineral ilmenite.

There are also various basins, impact craters, lava plains, and mountain ranges on the far side. Overall, the terrain is much more rugged and uneven compared to the lunar near side.

Why can’t we see the far side of the Moon from Earth?

We never see the far side of the Moon from Earth because of tidal locking. The Moon’s rotation causes the same side to always face Earth as it orbits around us. It would be possible to get a glimpse of the far side if the Moon rotated at a different speed than its orbital period. But tidal forces between the early Moon and Earth resulted in synchronous rotation, which keeps one hemisphere perpetually facing toward us.

Even though we can’t see the far side directly, we’ve been able to map most of the surface thanks to orbiting spacecraft. Lunar probes have flown around the Moon and mapped the topography, geology, and other features of the far side in detail. The Chang’e 4 lander and rover continue to study this mysterious region up close.

Can radio signals reach the far side of the Moon?

Because of the Moon’s synchronous rotation, direct communication between Earth and the lunar far side is blocked. Radio signals from Earth are not able to reach around to the far side without being refracted or going all the way around the Moon.

This lack of direct communication and data from the far side has presented challenges for lunar exploration. To overcome this, NASA’s Lunar Reconnaissance Orbiter and China’s Queqiao relay satellite have been used to communicate with spacecraft on the far side by orbiting around the Moon.

Queqiao orbits around a gravitationally stable point beyond the Moon, allowing it to maintain line of sight with both the lunar far side and Earth. This enables it to function as a communications relay between landers on the surface and ground controllers. A similar technique will likely be needed for future far side exploration.

Is the far side of the Moon actually dark?

The far side of the Moon often receives the misleading name of “dark side.” This makes it sound like that hemisphere somehow doesn’t receive any sunlight. In fact, the far side gets just as much sunlight as the near side we see from Earth.

Even though both hemispheres receive equal amounts of sunlight, the far side lacks direct visibility from Earth. Before the Space Age, this hemisphere was mysterious and hidden from view. But while it’s inaccurate to call it the dark side, the misnomer has stuck as this face remains perpetually hidden for those of us on Earth.

What is the Dark Side of the Moon?

In Pink Floyd’s 1973 album The Dark Side of the Moon, the term “dark side of the Moon” refers to the unknown and unfathomable aspects of the human condition rather than the actual far side of Earth’s moon. The album explores themes like conflict, greed, time, death and insanity.

While the album title plays on the mysterious nature of the unseen lunar hemisphere, the dark side discussed in the songs is not the real lunar far side. It’s a metaphorical shadow side representing the parts of life that can’t be seen or comprehended easily. The moon motif reflects introspection as the band analyzes darker elements of the human psyche and existence.

Could there be life on the far side of the Moon?

There is no evidence to suggest life exists on the far side of the Moon presently or in the past. The lunar far side lacks conditions needed to support life as we know it. It has an inhospitable airless surface with no liquid water, and is exposed to harsh temperature extremes and radiation.

Potential for past life on the Moon was likely extinguished billions of years ago when the Moon was volcanically active. Volcanism would have erased any biological traces on the surface. The Moon’s completely dry, barren terrain and lack of atmosphere or energy sources makes it an incredibly challenging environment for life to arise or survive.

Future missions and bases on the lunar far side will almost certainly find no life. While hypothetical lunar organisms could potentially exist deep below the surface, the chances are extremely slim. The Moon’s far side appears fully lifeless based on all data gathered so far by orbital and surface missions.

Can we build a lunar base on the far side of the Moon?

Building a future human outpost on the far side of the Moon is an intriguing possibility. The lunar far side has some potential advantages for a permanent base compared to the near side.

First, the far side always faces away from Earth, meaning there would be no radio interference from our planet. This benefit is ideal for locating radio astronomy observatories and telescopes on the far side, like China’s Queqiao relay satellite and the planned Lunar Crater Radio Telescope.

The far side’s terrain is also higher on average, offering more areas natural shielding against lunar temperature variations and cosmic radiation. More craters provide access to subsurface ice deposits. Constant solar power would be available atop crater rims with peaks in perpetual sunlight.

However, some challenges exist too. Communication would require a dedicated satellite around the L2 Lagrange point beyond the Moon. Transporting materials and people from the near side would need solutions. Still, the far side offers alluring strengths for a long-term human presence on the Moon.

What discoveries are still waiting to be found on the far side?

Many mysteries about the lunar far side are still waiting to be uncovered with future exploration. Some key questions include:

  • What is the composition of the South Pole-Aitken basin and far side highlands?
  • Are water ice and other volatiles more abundant on the far side?
  • How did large ancient impact basins form and shape this hemisphere?
  • What do craters and regolith reveal about the impact history?
  • Can natural shielding allow detectors to learn about the early universe?
  • Are there resources within craters suitable for In-Situ Resource Utilization?

Ongoing Chang’e and future Artemis missions plan to investigate these and other questions. Extensive sample return, geologic mapping, subsurface radar, and surface rovers could reveal more about the origin and evolution of the lunar far side. Each new mission chips away at the lingering unknowns on this unexplored part of the Moon.


The lunar far side remains the most alien landscape within reach of human exploration. Its hidden nature and advantages like shielding, resources, and visibility make it an intriguing location for future missions to study and settle. As technology enables more access, Earth’s perpetual lunar companion continues unveiling its secrets about the solar system’s history and makeup. The mysterious far side still has much to discover for those bold enough to reach its uncharted territory.

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