Typical forecasts on the moon are nowhere near comfortable, and temperatures range from boiling during the day to minus 280 at night. However, according to a new study, unique features known as moon craters could provide an oasis of rollercoaster temperatures.
To find out what it might be like inside these lunar craters, a team of planetary scientists at the University of California, Los Angeles, used thermal imaging from NASA’s Lunar Reconnaissance Orbiter and determined the temperature, at least in one of these craters, which is always 63 degrees. The findings were recently published in the journal Geophysical Research Letters, and the UCLA newsroom calls it a year-round “weather jacket” discovery.
One of the study’s authors, Tyler Horvath, has a PhD in planetary sciences. A student at the University of California said the crater could be an opening to a lava tube or cave and would be an ideal living place for astronauts, providing ideal temperatures as well as protection from meteorites and radiation.
“Imagine a full day on the moon… you have 15 days of extreme heat that goes beyond the boiling point of water. And then you have 15 days of extreme cold, which are some of the coldest in the entire solar system,” Horvath said. “So the ability to be in a place where you don’t have to expend energy to keep yourself warm all those 15 days of the night is almost invaluable because during the night, if you’re trying to use solar as the main form of getting energy, you can’t do that for 15 days.”
The UCLA research team focused on the chasm in the Sea of Tranquility or the Mari Trinquilites region, which is about 220 miles from the Apollo 11 landing site and also an equal distance from the Apollo 17 landing site.
Comfortable pixel on the moon
NASA’s LRO spacecraft is constantly orbiting the Moon, taking measurements with its instrument cluster, including the Diviner Lunar Radiometer, which has been continuously mapping the Moon’s heat emissions since 2009.
UCLA planetary scientist David Page is the Diviner instrument’s principal investigator and lead author of the new study on the moon’s crater.
Horvath has been commissioned to create a 3D model of one of these interesting craters in the Marie Trinquilites region. During that process, the team noticed a single pixel in the infrared images that was warmer than most spots on the moon at night when temperatures dip.
“We noticed that really fast he was able to warm up and maintain a much warmer temperature than it normally would on the surface at night,” Horvath explained. “We’re like, ‘Oh, this might be more exciting than we thought. “
After re-examining Diviner’s data and looking at the sunlight the pit was getting, the team determined the day’s daytime floor temperature of the crater. Unfortunately, this does not confirm the opening of the cave, but this is still the working theory about these craters formed by ancient volcanic activity.
“The result was remarkable that if there was a cave there, it would support temperatures of 63 F all the time, 24 seven every day in perpetuity, basically,” Horvath said.
How Trenquillitatis Crater and other caves on the Moon maintain their temperature is due to a physical concept known as a black body cavity, which can self-regulate to maintain its temperature.
“It’s basically a surface that’s an ideal source of radiation and an absorber of radiation,” Horvath explains.
The temperature at the bottom of the crater also depends on its position relative to the Earth and the Moon from the Sun.
“If you were close to the sun, the temperature would be hotter,” Horvath said. “If you were away from the sun, it would be much cooler.”
How did lava tubes form on the moon?
Even from Earth, it’s clear that the moon has interesting features, including craters of all shapes and sizes. In 2009, Japan’s moon-orbiting Kaguya spacecraft discovered a new type of lunar feature in the form of deep cavities that researchers believe may contain caves created by collapsed lava tubes, similar to those found on Earth.
Horvath explains that billions of years ago, intense volcanic activity and lava flows gave rise to the dark spots we see today when we look at the moon. The lava on the surface will cool first because it has been exposed to cold temperatures in space as the caverns below the lava are still flowing.
“In some places, that lava leaves completely and will leave a hollow tube, a lava tube under the surface,” Horvath said. “These pits are kind of our way of seeing that they’re there, that there’s a way to get to them, and they can be everywhere.”
NASA describes lunar craters as “manipulators” where the roof of a lava tube collapsed.
On Earth, the UCLA research team behind the study visited a lava tube in Hawaii Volcanoes National Park known as the Devil’s Throat, which is similar in size to the Mare Trenquillitatis crater. The park is home to other lava tubes like the one pictured above that visitors can walk through.
Without actually going to the moon and rock climbing into one of these craters, it would be difficult for researchers to tell if these vast caves even existed. Ultimately, it may be possible because in the next four years, NASA plans to return humans to the Moon and establish a permanent base.