Headline: The Extreme Temperature Swings on the Moon: A Challenge for Future Exploration
Subhead: From scorching hot to bone-chilling cold, understanding the Moon’s temperature fluctuations is key to future exploration and habitation.
Article:
The Moon, our nearest neighbor in space, appears as a cold, lifeless rock from Earth. But just how extreme are the temperatures on its surface? As it turns out, they’re dramatic, to say the least.
Just like on Earth, the Moon’s surface temperature varies depending on whether it’s in sunlight or not. "Temperatures can be very extreme, ranging from extremely hot to extremely cold," says John Monnier, a professor of astronomy at the University of Michigan, speaking to Live Science. "Temperatures on the Moon can range from around minus 100 degrees Celsius to more than 100 degrees Celsius," he adds.
For comparison, Earth’s average surface temperature is around 15°C, with a range of minus 89°C to 57°C, according to NASA. Despite being roughly the same distance from the Sun, the Moon’s temperatures are vastly different due to several factors.
For one, Earth has an atmosphere that traps heat and maintains a hospitable climate. The Moon, on the other hand, lacks atmosphere, making it vulnerable to direct solar heat, Monnier explains. Additionally, Earth’s vast oceans absorb and release heat gradually, while the Moon, being rocky, simply gets baked or frozen under the Sun’s light and dark, with its day-night cycle lasting about 29.5 Earth days.
The Moon’s soil, or regolith, is a "very good insulator," Monnier says. This means it holds onto heat or cold, and these temperature fluctuations vary across its surface. During missions Apollo 15 and 17, astronauts measured thermal flow underground. The subsurface, at least 35 cm down, is about 40-45 degrees Kelvin warmer than the surface, indicating that the Moon’s subsurface doesn’t experience the same extreme temperatures.
Near the Moon’s equator, temperatures can reach 121°C under sunlight and plummet to minus 133°C in darkness. After Mercury, the Moon has the most extreme thermal environment in our solar system.
At the lunar poles, the Sun never sets or rises. It’s always within 1.5 degrees of the horizon, casting long shadows that rotate with the Moon. This creates some permanently shadowed regions, or "cold traps," where temperatures could reach the lowest in the solar system, possibly as low as absolute zero or even colder.
These cold traps might harbor frozen water particles, which could be crucial for human life on the Moon. NASA’s Lunar Reconnaissance Orbiter (LRO), launched in 2009, has found some zones with temperatures around 17°C in permanently shaded craters, suggesting these could serve as viable spaces for human shelter.
However, understanding how temperatures vary across the Moon is vital for future exploration. Before we consider long-term lunar habitation or instrument deployment, we need to build equipment that can withstand both extreme heat and cold, Monnier says. This also helps us understand how the Moon’s insulating regolith interacts with various instruments to prevent overheating.
"If we want to have permanent human presence on the Moon, like a base, or if we want to have scientific instruments, we certainly have to know the temperatures and how they vary, so that we can build things that will survive," Monnier concludes. (Live Science/Z-3)
