What is the Moon Made of

The moon – the celestial pearl in the night sky – has captivated nature enthusiasts and scientists with its allure. From archaic myths to contemporary scientific exploration, its charm has been drawing humans to gape upward and brood over its enigmas.

But what is the mood made of? What are the secret ingredients the universe has used to bring this silver sail to life?

Let’s embark on a journey together and uncover the components of the moon.

What is the Moon?

The moon is the Earth’s only natural satellite, orbiting it with a rotation period of 29.5 Earth days. The gravitational forces between the Earth and the Moon induce tidal locking, causing the Moon to always face the Earth with the same side. The moon orbits the Earth, maintaining an average distance of 384,400 km from Earth—around 30 times the diameter of our planet. The moon—the Earth’s guardian orb—is around one-fourth the Earth’s size in terms of diameter and only 1/16 of its total surface area.

How Did the Moon Form?

Several theories and hypotheses have been proposed to explain the formation of the moon. However, the most prevalent and near-accurate one is the giant-impact hypothesis. It suggests that around 4.5 billion years ago, Theia, a protoplanet about the size of Mars, collided with the early Earth (proto-Earth). It was a highly impactful event that caused a significant amount of hot gas and molten rock to be flung out into space. This debris coalesced and turned into a disk of material encircling the Earth known as the lunar synestia. Coined in 2017, lunar synestia is a hypothesised fast-spinning, doughnut-shaped mass of vaporised rock. Over time, the materials in the disk accumulated and gathered together to bring the moon—the Earth’s celestial companion—to life. Around 60–175 million years after the solar system started its cosmic journey, the Moon was formed after the aforementioned colossal clash between Earth and the proto-planet Theia. It’s like mixing the Earth’s rocks in a giant blender, which played a pivotal role in building the fantastic Earth-Moon duo.

Race to the Moon

The race to the Moon traces back to the late 1950s when the then Soviet Union launched Sputnik, the world’s first artificial satellite to orbit the Earth, in 1957. It circled the Earth for nearly three months before the radio transmitter batteries depleted, and it continued to orbit for around two more months silently before returning to Earth’s atmosphere and burning up. The incredible success of this mission sparked a silent war between the USA and the Soviet Union, driving both to launch more missions to the tranquil moon.

Early Space Missions

Following the success of Sputnik, the Soviet Union continued to achieve milestones in space exploration, including sending the first human, Yuri Gagarin, into space in 1961. This historic flight intensified the space race and spurred the United States to accelerate its efforts in manned space missions.

American Response

In response to the Soviet achievements, the United States ramped up its space program under NASA. Project Mercury, initiated in 1958, aimed to put American astronauts into orbit. This was followed by Project Gemini, which focused on developing space travel techniques for future Moon missions.

Apollo Program and Lunar Landing

The long-standing success humankind waited for came with the success of the Apollo program. Launched by NASA, Apollo 11 was the first spaceflight to land humans on the moon’s surface. Neil Armstrong and Buzz Aldrin were the first humans ever to walk on the land of the Earth’s only natural satellite.

The Apollo missions were built on the relentless efforts and perseverance of the astronauts.

NASA’s attempt to send humans to the moon traces back to 1968 when the astronauts of Apollo 8 returned to Earth after successfully orbiting the Moon.

The success of this mission encouraged NASA to launch more missions, culminating in the iconic Apollo 11 mission, which successfully landed the first humans on the moon. It was followed by the success of five more missions, four of which made it to the moon. With this, the moon—the silent sentinel of the night—became the only celestial orb that we could ever set foot on.

Part of NASA’s Apollo program was Apollo 15, a6 and a7 that re-entered the Earth’s atmosphere carrying rocks and soil samples from the moon for scientific study.

Meanwhile, the Soviet Union was planning robotic exploration throughout the 1960s and 1970s. After a number of failed missions, the country successfully landed Luna 16 on the Moon in 1970. It became the first robotic mission that brought back soil samples from the moon. It was followed by Lunokhod 1, the first lunar rover traversing the Moon’s surface. In 1973, Lunokhod 2 was launched, setting an off-world distance-driving record that stood for over 40 years by traveling about 23 miles (37 kilometers) on the surface of the moon. The record was broken in 2004 by NASA’s Opportunity rover on Mars.

Active Missions

• Queqiao-2: Launched on March 19, 2024, Queqiao-2 is China’s landmark mission for facilitating lunar communication. The capabilities of this lunar communications relay satellite were doubled by incorporating it with Tiandu-1 and Tiandu-2, two other experimental communication satellites.
• Danuri: KPLO (Korea Pathfinder Lunar Orbiter): Launched in 2022 as part of Korea Pathfinder Lunar Orbiter (KPLO) mission, Danuri is the country’s first-ever satellite launched to orbit the moon. The Korea Aerospace Research Institute (KARI) designed and developed it to establish basic lunar exploration technologies for the country. Besides, it’s expected to dig deeper into the lunar topography, environment, and resources to facilitate further research.  
• CAPSTONE: Managed by Advanced Space and funded by NASA, the CAPSTONE spacecraft is dedicated to validating a fuel-efficient elliptical lunar orbit, a key element for the future NASA-led international Gateway space station. CAPSTONE’s mission is to demonstrate the feasibility of this unique orbit for future lunar missions, paving the way for sustainable lunar exploration.
• Lunar Reconnaissance Orbiter (LRO): Launched by NASA, the Lunar Reconnaissance Orbiter is a pivotal robotic mission dedicated to mapping the Moon’s surface. Since its launch, LRO has provided valuable data and insights about the Moon, leading to groundbreaking discoveries and advancements in lunar science and exploration.

Upcoming Lunar Missions

The next few years hold exciting prospects for lunar exploration, with a series of upcoming missions planned by NASA and the China National Space Administration (CNSA) to delve deeper into the mysteries of the Moon. These missions encompass a range of objectives, from conducting surveys and technology tests to returning lunar samples and exploring the Moon’s polar regions. Each mission contributes to our expanding knowledge of Earth’s celestial companion and sets the stage for future endeavors in lunar exploration and utilization.

• Peregrine Mission 1 – NASA CLPS Lunar Lander (2024): A mission by Astrobotic’s Peregrine lander to deliver payloads to the Moon.
• IM-1 – NASA CLPS Lunar Lander (2024): A mission under NASA’s Commercial Lunar Payload Services program to transport payloads to the lunar surface.
• Lunar Trailblazer – NASA Lunar Orbiting Small Satellite (2024): A satellite mission to study the Moon’s water resources from orbit.
• Prime 1 – NASA CLPS Lunar Lander (2024): A mission aimed at delivering payloads to the Moon’s surface.
• Griffin Mission 1 – VIPER – NASA Lunar South Pole Rover (2024): NASA’s mission to send the VIPER rover to explore the lunar South Pole for water ice.
• Blue Ghost 1 – NASA Lunar Lander (2024): A NASA mission involving a lunar lander for various activities on the Moon.
• Chang’e 6 – CNSA (China) Lunar Sample Return Mission (2024): China’s mission to retrieve lunar samples from the Moon.

What Is the Moon Made Of?

The Moon – the Earth’s special sidekick – is made up of different layers where heavier materials (iron, nickel, pyroxene, olivine, etc.) sink closer to its core, and lighter materials drift towards its surface. These heavier materials are the main constituents of the moon’s mantle and core, whereas the crust is made up of lighter materials (aluminum, silicon, and oxygen). Let’s go through the constituents of the moon together:

The Lunar Core

At the center of the moon is a core thought to be made up of metallic iron alloy, blended with a small amount of sulfur and nickel. Compared to the core of other planets, such as Earth, the moon’s core is small and constitutes only 20% of its diameter. How much tinier the moon’s core is can be understood by comparing it with the cores of other planets. For example, the Earth’s core takes up around half of its diameter. The diminutive size of the Moon’s core makes it unique and adds to its allure.

The Lunar Mantle and Crust

Mantle and crust are essential elements of the moon. The crust is the outermost layer of the moon, thinner on the side facing the Earth compared to the other side. The key elements making up this layer are anorthosites—a phaneritic intrusive igneous rock composed of plagioclase feldspar and aluminum. Underneath the crust lies the mantle. With a thickness of around 1350 km, the mantle extends as deep as 2900 km. deeper than the crust. The crust is only 50 km thick. 

The difference in the composition of these layers indicates that, at the early stage, the moon was a large ocean of magma. Over time, the magma started to cool down. This cooling process turned lighter magma material into crystal-like substances at the surface and formed the crust.  Heavy materials in the mantle, for example, pyroxene and olivine, – dipped down into the magma ocean.

Lunar Terrain

The moon’s surface is like a celestial artwork created by the lightened highlands and the dark, lava-filled maria. The difference in the surface is a testament to the sizzling past that indicates how the magma ocean created cystalised lunar crust with rocks of different ages and compositions. The cratered surface of the moon sheds light on the impact features in the formation of this natural satellite.

Almost the entire lunar terrain is covered with a thick layer of lunar regolith – finely fragmental and unconsolidated rock material that includes rocky debris and loads of charcoal-gray, granular dust. Beneath it lies megaregolith – a large-scale and mostly broken layer made of a mixture of rock and mineral fragments produced by impact cratering. The moon’s surface is often hard hit by space rocks, comets, and meteoroids, as it has no air to prevent impact cratering. This process continued over billions of years, causing the moon’s surface to break down into chunks of pieces of different shapes and sizes.