It really won’t be easy for humans to create a habitat on the moon, but a new discovery could alleviate some problems.
Analysis of the radar data suggests that a gaping hole in the lunar crust could lead to a network of caves that future lunar explorers could use for shelter. We have known for some time about holes called “earrings” in the surface of the Moon; now we finally have evidence that they exist.
“These caves have been theorized for more than 50 years, but this is the first time we have demonstrated their existence,” said astronomer Lorenzo Bruzzone of the University of Trento in Italy.
The environment on the moon is very different from the one we evolved in, so it’s not very good for human physiology. No atmosphere to breathe, for example. And then there are the temperatures. A day on the moon lasts about 14 days, as does the night. During the day, temperatures can reach as high as 121 degrees Celsius (250 Fahrenheit), but then drop to -133 degrees Celsius (-208 Fahrenheit) after sunset.
Not to mention solar and cosmic radiation. Earth’s atmosphere protects us from the worst; The moon is a radiation environment that would be considered hazardous to human health.
Cue lava tubes. They are created when lava solidifies on the surface as it continues to flow below. Eventually, the underground lava flow drains away, leaving a hollow cavity beneath the already solid volcanic rock layer – a natural cave.
They can occur anywhere there has been volcanic activity. We have them here on Earth, they’ve been spotted on Mars, and entire networks are thought to exist on the Moon.
These lunar lava tubes are of great interest to scientists designing lunar exploration missions, as they would provide protection for a human lunar base from the harsh surface environment. But positively identifying a cave system from holes in the lunar surface alone is a bit of a challenge.
Now, led by astronomer Leonardo Carrer of the University of Trento, a team of researchers say they have finally made such an identification.
The observations come in the form of radar data collected in 2010 by NASA’s Lunar Reconnaissance Orbiter. While flying over an ancient lunar basalt plain called the Sea of Tranquility, he noticed a hole in the surface of the Moon; a skylight that appears when part of a lava tube collapses.
“Years later, we reanalyzed this data with sophisticated signal processing techniques that we recently developed and found radar reflections from the pit area that are best explained by an underground cave conduit,” says Bruzzone.
“This discovery provides the first direct evidence of an accessible lava tube beneath the surface of the Moon.”
The next step was to model the shape of the tunnel under the skylight. The best explanation for the structure, the researchers found, is a lava tube that extends from the skylight into the moon’s interior.
Now we can’t just write down any old place on the moon. The landing site, especially for a manned mission, must be carefully considered. We’ve already sent people to the Sea of Tranquility, so it’s unlikely to be high on the list for the next mission, especially since the polar regions have exciting features to check out, like craters with possible water ice.
But the discovery of one lava tube on the moon means there are likely more up there waiting to be discovered. And identifying where they are can help narrow down the best locations for a long-term lunar base.
“This research,” says planetary geologist Wes Patterson of Johns Hopkins University, “demonstrates both how lunar radar data can be used in new ways to address fundamental questions for science and research, and how important it is to continue to collect remotely sensed lunar data.”
The study was published in Natural astronomy.
