CNN
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Scientists have long theorized the existence of caves on the Moon. Volcanic activity It is connected to the Holes covering the surface of the moonNow, an international team of researchers has found the first direct evidence that the deepest hole on the Moon’s surface is connected to a cave that could provide refuge for astronauts.
As the US, China, and other countries race to establish lunar exploration bases, identifying areas on the moon that can protect humans and robotic rovers from the harsh lunar environment, including strong radiation and extreme temperatures, could be crucial to future space exploration. Long-term human presence It is the closest natural satellite to the Earth.
To find the caves, the team investigated recorded radar readings of holes in the vast plains. Sea of Tranquilityor the Sea of Tranquility, Apollo 11 Mission 1969.
NASA’s lunar rover collected radar data, which uses wavelengths to detect what’s beneath the surface, in 2010. After analyzing the data, researchers found empty space 130 to 170 meters (426 to 558 feet) below the surface, according to a study published Monday. Journal “Nature Astronomy”.
The newly discovered cave is at least 45 meters (about 148 feet) wide and 30 to 80 meters (98 to 262 feet) long, and may be just the first part of a longer, tubular cavity formed by the lava, and it is likely that there are even more caves yet to be discovered, the researchers said.
“Lunar caves have remained a mystery for a long time; scientists have hypothesized their existence for more than 50 years, so it was a surprise to finally be able to prove the existence of underground conduits,” Leonardo Carrell, assistant professor in the Department of Informatics and Computer Science at the University of Trento in Italy and co-author of the study, said in an email.
Future research and exploration of lunar caves will help to understand the evolution of the Moon and Lunar volcanismthe authors point out in their study.
“Caves are unique environments that preserve the history of the Moon,” study co-author Lorenzo Bruzzone, director of the Laboratory for Remote Sensing and professor of telecommunications at the University of Trento, said in an email. “Analyzing rocks in caves may enable new discoveries about the evolution of the Moon, including the timeline and duration of volcanic activity on the Moon and the actual composition of the lunar mantle.”
“Furthermore, (the lunar caves) could be an alternative or integration to a lunar base,” he added.
Near the moon’s equator, average temperatures reach 250 degrees Fahrenheit (121 degrees Celsius) during the day and plummet to minus 208 degrees Fahrenheit (minus 133 degrees Celsius) at night. According to NASA:Severe temperatures can drop below -410°F (-246°C), as recorded by the Lunar Reconnaissance Orbiter.
The researchers July 2022 Survey They investigated several holes on the surface of the moon, some of which appeared to lead to caves. NASA at the time of discovery We found that the temperature was much more stable in the shaded shelter, remaining steady at about 63 F (17 C).
“We’re really excited to find new evidence of caves extending from the bottom of the Mare Tranquility,” Tyler Holbert, lead author of the 2022 study and a planetary science doctoral student at the University of California, Los Angeles, said in an email.
“Lunar caves could be of great benefit to astronauts and rovers, providing protection from lunar hazards such as radiation, micrometeorites, and extreme temperatures. They could also open the door to long-term, large-scale human habitation on the Moon,” added Holbert, who was not involved in the new study.
There are more than 200 known Mare Tranquility-like holes on the moon, but only a handful likely extend into caves, Holbert said, and some lava tubes may be inaccessible because of debris blocking the passageways, Carrell added.
The interior of the newly discovered cave remains unknown until more information is gleaned from rovers and human exploration. The interior is similar to recently formed lava tubes on Earth, but much larger, Holbert said. It will probably appear to have smooth walls, except for places where dripping lava may have formed ridges or protrusions called lavasicles. The cave will also be pitch black except for places where sunlight reaches and reflects off the bottom of the hole, added Paul Hayne, an associate professor in the Department of Astrophysics and Planetary Sciences at the University of Colorado Boulder.
The caves’ large size isn’t surprising: The moon’s lower gravity can affect the stability of lava tubes, with larger caves at lower risk of collapse, said Hayne, who co-authored the 2022 study but was not involved in the current one. Most of Earth’s lava tubes are found in Hawaii, the Canary Islands, Australia and Iceland. 33 to 98 feet in diameter. Survey conducted in August 2020 It suggested that lava tubes on the moon could reach diameters of up to 1 kilometer (3,280.84 feet).
“It would not be surprising if future missions uncover even larger caverns, providing a glimpse into the Moon’s interior volcanic plumbing system,” Hayne said in an email.
The authors of the new study found that the caves may be flat or slope at angles of up to 45 degrees, suggesting that they may be accessible, Carrell said.
But given the depth of this cave (and possibly other lunar caves), lowering astronauts to the pit floor may require some ingenuity, including the use of rock-climbing equipment such as ropes and belay devices, as well as large cables for equipment and building materials, Hayne said. Eventually, more permanent structures, such as cargo elevators, may be needed, he added.
Other ideas for exploring the deep holes of the Mare Tranquility and newly discovered caves within it include using a robotic crane, currently being explored by rovers, to lower astronauts and rovers to the surface. European Space Agency.
Moon watchers can identify the Mare Tranquility, where the caves were discovered, by looking for a wide, dark plain, said Noah Petro, director of NASA’s Planetary Geology, Geophysics and Geochemistry Laboratory. He encouraged people to look up to the sky and peer into the spot on July 20, the 55th anniversary of the Apollo 11 landing, the first manned moon landing mission.
“The discoveries (of possible holes or caves) go back several years, but when we look at this new information from the radar data, we’re saying, ‘Wow, wow, it’s a little bigger than we expected,'” said Petro, project scientist for both the Lunar Reconnaissance Orbiter and the Artemis 3 mission, which aims to land humans on the moon for the first time since Apollo 17 in 1972. Petro was not involved in the new study.
“LRO has been on the Moon for 15 years, creating incredible data sets that have changed our view of the Moon and led to discoveries like this one,” Petro said. “This cave is one of the great surprises the Moon always has in store for us.”
