The idea of walking on the Moon captures the imagination, inviting thoughts of vast, desolate landscapes. Exploring how long such a journey might take reveals not only the Moon’s physical characteristics but also the profound challenges of human exploration beyond our home planet.
The Moon’s Dimensions and a Simple Calculation
To understand how long it might take to walk around the Moon, one must first consider its size. The Moon has an equatorial circumference of approximately 10,917 kilometers (6,783 miles). For comparison, Earth’s equatorial circumference is about 40,075 kilometers, making the Moon roughly 27% the size of our planet.
On Earth, an average human walking speed is commonly considered to be around 5 kilometers per hour (3.1 miles per hour). This serves as a reasonable estimate for a continuous, unimpeded walk. Applying this speed to the Moon’s circumference suggests it would take approximately 2,183.4 hours to walk around the Moon. This translates to roughly 91 Earth days of continuous walking. This initial figure, however, is purely theoretical, assuming Earth-like conditions and uninterrupted progress.
Lunar Environment and Practicalities of a Walk
Walking on the Moon involves more than covering distance; the lunar environment presents numerous challenges that drastically alter any simple time calculation. The Moon’s gravity is about one-sixth (16.6%) of Earth’s gravity. While reduced gravity allows for higher jumps, it also affects stability and the effort required for forward momentum. Astronauts on the Apollo missions often found that a “loping” or hopping gait was more efficient than a traditional walk, as it helped manage movement in low gravity.
A lack of atmosphere on the Moon necessitates a pressurized space suit. These suits are bulky and stiff, significantly impeding movement and requiring considerable effort to bend joints. An Apollo-era space suit, including its life support backpack, weighed around 82 kilograms (180 pounds) on Earth, feeling like only about 13.6 kilograms (30 pounds) on the Moon due to lower gravity.
The Moon experiences extreme temperature swings. Daytime temperatures can reach approximately 120-127°C (250-260°F), while nighttime temperatures plummet to about -130°C to -173°C (-208°F to -280°F). These fluctuations, occurring over a lunar day that lasts about 29.5 Earth days (with roughly 14 Earth days of sunlight and 14 Earth days of darkness), require advanced thermal regulation within the space suit and limit continuous activity.
The lunar surface also lacks atmospheric and magnetic field protection, exposing anyone on it to harmful radiation. Radiation levels are two to three times higher than those on the International Space Station and approximately 200 times higher than on Earth’s surface, with measurements indicating around 60 microsieverts per hour. This necessitates substantial shielding, often envisioned as habitats constructed with thick layers of lunar soil, limiting the duration of surface excursions.
The Moon’s terrain is characterized by numerous impact craters, mountains, valleys, and vast plains. The surface is covered in a fine, abrasive dust called regolith, which has sharp, jagged edges because it is not eroded by wind or water. Navigating this rugged, uneven, and potentially slippery landscape would require slow, deliberate movements, making a smooth, continuous walk impractical.
The logistics of sustaining such a long journey would be significant. A continuous walk would require a constant supply of oxygen, water, food, power, and waste management. Current plans for sustained lunar exploration involve complex resupply missions, with astronauts needing between 1 to 6 tons of supplies per mission for long durations. This logistical challenge means a continuous “walk” around the Moon is not feasible. Any long-distance traverse would involve a series of short excursions between established habitats or resupply depots, extending the overall journey time and transforming it into a multi-year expedition.