New Cave Discovery on the Moon

For decades, scientists have theorized that the moon is riddled with underground tunnels and caverns, remnants of its volcanic past. A groundbreaking study published in Nature Astronomy has finally provided hard evidence to support this. Researchers have confirmed the existence of a substantial underground cave accessible from the Mare Tranquillitatis, the famous “Sea of Tranquility” where humans first walked. This discovery shifts the conversation from theoretical lunar geology to tangible planning for future lunar bases.

The Breakthrough at Mare Tranquillitatis

The discovery centers on a specific feature known as the Mare Tranquillitatis Pit (MTP). While the pit itself—a “skylight” or hole in the surface—was already known, what lay beneath it remained a mystery until now.

A team of researchers led by Leonardo Carrer and Lorenzo Bruzzone from the University of Trento in Italy achieved this breakthrough not by launching a new rocket, but by looking back at old data. They re-analyzed radar images captured in 2010 by NASA’s Lunar Reconnaissance Orbiter (LRO). Specifically, they utilized data from the Mini-RF instrument, which is a miniature radio-frequency radar.

How They Found It

The team used complex signal processing techniques to look at the radar reflections coming from the pit. They discovered that the radar brightness increased on the western side of the pit as the sun angle changed. This specific pattern indicated that the radar waves were bouncing off an underground wall and ceiling.

Simulations confirmed that this signature could only explain a conduit extending underground. The data suggests the cave starts at the bottom of the pit, which is about 100 meters deep. The cave itself appears to be between 30 and 80 meters long and around 45 meters wide. To put that in perspective, this is spacious enough to house a large lunar infrastructure or several city blocks worth of habitat.

Why This Cave Changes Everything

Finding a hole in the ground might sound trivial on Earth, but on the Moon, it is the holy grail for habitation. The lunar surface is an incredibly hostile environment for humans and machinery.

Natural Protection

Astronauts on the surface face three primary threats:

1. Cosmic Radiation: Unlike Earth, the Moon has no atmosphere or magnetic field to block high-energy particles from the sun and deep space. Long-term exposure is lethal.
2. Micrometeorites: Tiny space rocks constantly bombard the lunar surface at bullet-like speeds.
3. Temperature Swings: The surface temperature fluctuates wildly. During the lunar day, it can boil at 127°C (260°F), and at night, it plunges to -173°C (-280°F).

This newly confirmed cave solves all three problems simultaneously. A ceiling of solid rock, tens of meters thick, provides a powerful shield against radiation and meteorites. Furthermore, data suggests that the temperature inside these caves is remarkably stable, hovering around a comfortable 17°C (63°F). This means future habitats would not need energy-intensive heating or cooling systems to keep astronauts alive.

The Geology of Lunar Lava Tubes

The structure discovered in Mare Tranquillitatis is likely a lava tube. These form when molten lava flows across the surface. The top layer cools and hardens into a solid crust, insulating the liquid lava moving beneath it. Once the eruption ends and the lava drains away, a hollow tunnel remains.

We see similar structures on Earth in volcanic regions like Hawaii, Iceland, and the Canary Islands. However, lunar gravity is much weaker than Earth’s gravity. This allows lunar lava tubes to be much larger without collapsing. Some theoretical models suggest there could be tunnels on the Moon wide enough to fit an entire city inside. The cave found by the University of Trento team is likely just a small section of a much larger network.

Implications for the Artemis Program

This discovery is particularly timely given NASA’s Artemis program, which aims to return humans to the Moon and establish a sustained presence. The Mare Tranquillitatis is located near the lunar equator. While the current focus for Artemis is the lunar south pole (due to water ice deposits), the confirmation of accessible, habitable caves near the equator offers a compelling alternative or secondary site.

Developing a base inside a cave requires different engineering than building on the surface. We would need technology to lower equipment into the pit, such as cranes, elevators, or rappelling robots.

Recent concepts, such as the DAEDALUS robot developed by the University of Würzburg, describe sphere-shaped devices designed to be lowered into these skylights to map the interior with 3D LIDAR and cameras. The confirmation of the Mare Tranquillitatis cave provides a specific target for these future robotic scouts.

A Gateway to Subsurface Exploration

The Mare Tranquillitatis pit is the deepest known pit on the Moon, leading into a void that has remained untouched for millions, perhaps billions, of years. Beyond habitation, this cave offers a pristine scientific record.

Rocks inside the cave have not been eroded by solar wind or micrometeorites. They could contain undisturbed geological layers that reveal the history of lunar volcanism. Exploring this cave is not just about finding a home; it is about reading the untouched history of our closest celestial neighbor.

Frequently Asked Questions

Where is the new moon cave located? The cave is located in the Mare Tranquillitatis (Sea of Tranquility), accessible via a large pit known as the Mare Tranquillitatis Pit (MTP). This is the same general region where Apollo 11 landed in 1969.

Is the cave big enough for humans? Yes. The radar data indicates the cave is approximately 45 meters (147 feet) wide and up to 80 meters (262 feet) long. It is located at the bottom of a pit that is over 100 meters deep.

Why is an underground cave better than a surface base? A cave provides natural shielding from deadly cosmic radiation and micrometeorites. It also maintains a stable internal temperature (around 17°C/63°F), whereas the surface experiences extreme swings from boiling heat to freezing cold.

How did scientists find it? Researchers from the University of Trento analyzed radar data collected in 2010 by NASA’s Lunar Reconnaissance Orbiter (LRO). They identified radar reflections that indicated a hollow underground passage extending from the pit.

When will humans explore this cave? There is no set date for a human mission into the cave. However, robotic missions will likely investigate first to map the stability and extent of the tunnels before astronauts attempt to enter.