Temperatures in the shaded area of this pit in the Mare Tranquillitatis region remain stable at around 17 degrees Celsius (63 degrees Fahrenheit). Scientists said the pit likely leads to an equally temperate lava cave. Moon caves could be an option for future housing for human explorers. Image via NASA/GSFC/Arizona State University/UCLA.
If future explorers want to live and work on the Moon, they will need a hospitable environment. The Moon has virtually no atmosphere, so daytime temperatures on the Moon can reach 260 degrees Fahrenheit (126° Celsius), while nighttime temperatures can drop to -280 F (-173 C). But a team of scientists announced on July 26, 2022 that they found pits and caves on the Moon that have a permanent temperature of 63 F (17 C). It’s what scientists call sweater time.
The team of scientists included Tyler Horvath and David Paige of UCLA and Paul Hayne of the University of Colorado Boulder. They published their study on July 8, 2022 in the peer-reviewed journal Geophysical Research Letters.
Lunar caves, pits and lava tubes
Scientists have known about craters on the Moon since 2009. NASA’s Lunar Reconnaissance Orbiter (LRO) found more than 200 craters on the Moon. Horvath said:
About 16 of the more than 200 pits are probably collapsed lava tubes.
The Earth is also home to lava tubes, such as those that visitors can tour in Hawaii Volcanoes National Park. They form when rivers of lava cut paths beneath lava flows, or when the outer crusts solidify. Mares or “seas” on the moon are ancient lava flows that have solidified into plains. Lava tube entrances appear as pits once the crust above a lava tube collapses to a thin point.
When they analyzed craters on the Moon, scientists found that two of the most prominent craters have visible exits. They said they clearly lead to some kind of cave or void. They also believe there is strong evidence of a large cave from the overlying third pit.
Scientists believe that some lunar craters could lead to lava tubes, similar to the one in Hawaii Volcanoes National Park. The moon is home to similar tunnels, left behind after molten lava flows beneath the surface. Image via Frank Schulenberg/Creative Commons/UCLA.
Taking the temperature of the moon
Horvath analyzed images from LRO’s thermal camera, the Diviner lunar radiometer experiment, to check temperatures inside the wells compared to the surface. At Mare Tranquillitatis, he studied a cylindrical depression roughly the length and width of a football field. Using computer modeling, researchers could track temperature changes in the pit over time.
What they found was that temperatures remained relatively stable at about 63 F (17 C) in the shadows. And they said any cave or tube leading out of the pit would also maintain that relatively comfortable temperature.
The key to the constant temperature, the researchers said, is the overhangs. It prevents shady places from getting too hot during the day and the heat escaping at night. The areas of the pit where the sun reaches are baked to 300 F (148 C), even hotter than the surface of the moon. Horvath said:
Because the Tranquillitatis crater is closest to the lunar equator, the midday-lit floor is probably the hottest place on the entire moon.
View larger. | Scientists say pits on the moon could lead to caves or lava tubes where temperatures would be comfortable for future human explorers to live and work in. Image via NASA/GSFC/Arizona State University.
Moon caves are a welcoming environment for humans
Extreme temperatures on the Moon are a challenge for humans setting up any permanent lunar base. A day on the Moon lasts about 15 Earth days, and a night lasts about 15 Earth days. This would mean that solar energy on the Moon would be inaccessible about half the time. Moon caves would remedy this problem, along with others. Lunar caves will also provide some protection from cosmic rays, solar radiation, and micrometeorites. Paige said:
Humans evolved living in caves, and we could return to caves when we live on the Moon.
The best heatmap in the universe
The Diviner lunar radiometer experiment has been mapping the moon since 2009. It has now produced the most detailed and comprehensive thermal measurements of any object in our solar system, including Earth. The researchers had to align the many thermal camera images until they had a thermal reading accurate to a single pixel. Horvath explained:
Since no one else had looked at such small things with Diviner, we found it had a bit of double vision, which made all our maps a bit blurry.
Future exploration of moon caves
A proposed Moon Diver mission aims to send a rover down and explore the Tranquillitatis pit. You can also read about the tiny PitRanger, designed to explore pits on the moon.
Concept art of a PitRanger examining a lunar pit. Image via William Whittaker / USRA / Carnegie Mellon University.
Conclusion: Scientists announced that the moon’s caves, shadow pits and lava tubes have locations where temperatures hover around a comfortable 63 degrees Fahrenheit (17 degrees Celsius). These would be perfect places for future explorers to live and work.
Source: Thermal and Illumination Environments of Lunar Pits and Caves: Models and Observations from the Diviner Lunar Radiometer Experiment
via UCLA
Through NASA
Kelly Kizer Whitt
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Kelly Kizer Whitt has been a science writer specializing in astronomy for more than two decades. He began his career at Astronomy Magazine, and has been a regular contributor to AstronomyToday and the Sierra Club, among other outlets. His children’s picture book, Solar System Forecast, was published in 2012. He has also written a dystopian novel for young adults entitled A Different Sky. When she’s not reading or writing about astronomy and stargazing, she enjoys traveling to national parks, doing crossword puzzles, running, tennis, and paddleboarding. Kelly lives with her family in Wisconsin.