NASA
The Earth rises above the lunar horizon in this photo taken from NASA’s Apollo 17 spacecraft in orbit during the Apollo program’s final lunar landing mission.
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A new study suggests that the spacecraft left behind by American astronauts on the moon may be causing small tremors known as moonquakes.
Researchers have revealed for the first time a previously unknown form of seismic activity on the moon through analysis of Apollo-era data using modern algorithms.
The large-scale temperature fluctuations occurring on the moon’s surface could cause man-made structures to expand and contract, causing vibrations, the report suggests. According to a news release about the research, the lunar surface is an extreme environment, with temperatures ranging from -208 degrees Fahrenheit (-133 degrees Celsius) in the dark to -250 degrees Fahrenheit (121 degrees Celsius) in direct sunlight.
In fact, the entire surface of the moon expands and contracts in cold and hot weather, says a study published in the journal Science on September 5th. Geophysical Research Journal: Planets.Yet scientists were able to use some kind of artificial intelligence A deep understanding of Apollo-era data allows researchers to pinpoint the gentle shaking emitted by Apollo 17’s Lunar Module module, located hundreds of yards from instruments recording lunar earthquakes. They were able to identify it. overview Research results from researchers at institutions such as the California Institute of Technology and NASA. (NASA funded the research.)
This analysis provides new insights into how the Moon responds to its surrounding environment and what influences its seismic activity. The rumbling sounds are not dangerous and would probably be imperceptible to humans standing on the moon.
Understanding moonquakes could be essential for future exploration if NASA and its partners build a permanent outpost on the moon’s surface, experts said. Artemis, the agency’s lunar exploration program.
“How strong do we need to build a structure, and what other hazards do we need to mitigate?” Angela Marciak, Ph.D., an assistant professor at the University of Arizona’s Lunar and Planetary Institute, said this kind of talked about questions that data analysis could help answer. Marciak was not directly involved in the study, but was in contact with the authors as a fellow lunar seismology expert.
Marciak pointed out that all Apollo missions had equipment to detect moonquakes.but Apollo 17 missionLaunched in 1972, the satellite was notable for leaving behind a set of seismometers capable of detecting hot moon earthquakes, tremors caused by rapid heating and cooling of the moon’s surface.
“Thousands of these signals were recorded over an eight-month period in 1976-1977 by four seismometers deployed during the Apollo 17 lunar seismic profiling experiment, but the data quality was poor. “This makes analysis difficult,” the researchers wrote. “We developed algorithms to accurately determine the timing of wave arrival, measure the strength of seismic signals, and find the direction of the lunar epicenter.”
Scientists revisited the data for the first time in decades. The new analysis allows the researchers to conclude that a particular type of lunar quake, called an impulsive thermal moonquake, is not a natural source, but is caused by the heating and cooling of a nearby spacecraft.
“Every morning on the moon, as the sun hits the lander, the lander begins to eject,” study co-author Allen Hasker, research professor of geophysics at Caltech, said in a statement. “There was another one every five to six minutes for five to seven hours of Earth time. They were incredibly regular and repetitive.”
This tremor The study says this is different from another type of lunar quake called an emergency hot lunar quake, which is likely caused by the ground’s natural response to exposure to sunlight.
The researchers said they hope future lunar exploration will provide a more complete picture of the phenomenon.
Apart from thermal earthquakes, the moon is also known to cause earthquakes. deep shaking and shallow shaking The same goes for activity thought to be caused by meteorite impacts.
It is important to note an important difference between the Moon and Earth. There are no changes on the moon’s surface. plate It can cause catastrophic events. But the moon has active internal life, and, like on Earth, certain types of seismic events can occur anywhere and at any time on the lunar surface, Marciak said.
Marciak was interested in India’s lunar lander mission, Chandrayaan-3, which is equipped with a seismometer. The Indian Space Research Organization has already confirmed The device was able to detect a lunar earthquake. (ISRO researchers have not yet published extensive data on the records or proposed any possible causes for this phenomenon.)
Chandrayaan-3, which was the first to record activity near the moon’s south pole, went dormant in early September. Researchers will try to wake up the spacecraft to collect more data on September 22, when the Chandrayaan landing site will see sunlight again.
“We hope that the Artemis program will continue to include seismometers, because they will be very important in understanding what is happening not just at the surface, but deeper into the regolith. Because it’s important,” Marciak said.
But scientists are enthusiastic that combing through Apollo-era data using modern technology could yield fascinating new results.
“It’s important to learn as much as possible from existing data so we can plan experiments and missions to answer the right questions,” Hasker said. “The Moon is the only planet other than Earth that has multiple seismometers installed at once. It gives us the only opportunity to thoroughly study other bodies.”