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A new era of space exploration will begin in 2024, when NASA sends astronauts to the moon as part of the Artemis mission, a sequel to the 1960s and 1970s Apollo missions on life.
According to the “RT” website, in a research article published in the journal Science Advances, University of Rochester researchers leading a team of colleagues from seven other institutions shared their findings on one factor key affecting the types of resources that can be found. on the moon. : The Moon has never had a long-lived magnetic shield in its 4.53 billion year history.
The presence or absence of a shield is important because magnetic shields protect astronomical objects from harmful solar radiation.
The team’s findings conflict with some old assumptions, according to the study’s lead author John Tarduno, professor of geophysics in the Department of Earth and Environmental Sciences and dean of research in the arts. , science and engineering in Rochester.
For years, Tarduno has been a pioneer in the field of paleomagnetism, studying the evolution of the Earth’s magnetic shield as a means of understanding planetary evolution and environmental changes.
The Earth’s magnetic shield originates from the core of the planet. There, the swirling liquid iron generates electric currents, leading to a phenomenon called geodynamo, which produces the shield.
The magnetic shield is invisible, but researchers have long recognized that it is essential for life on Earth because it protects our planet from the solar wind, from the fluxes of radiation from the sun.
Although the Moon does not have a magnetic shield now, there has been some debate as to whether or not the Moon had an extended magnetic shield at some point in its history.
“Since the Apollo missions, the idea that the moon has a magnetic field as strong or stronger than the Earth’s magnetic field has been around for about 3.7 billion years,” says Tarduno.
The belief that the moon contained a magnetic shield was based on an early data set from the 1970s that included analyzes of samples collected during the Apollo missions. The analyzes showed that the samples exhibited magnetization, which the researchers said is caused by the presence of geodynamo.
“The lunar core is very small and it would actually be difficult to drive this type of magnetic field,” explains Tarduno. Moreover, previous measurements that recorded a high magnetic field had not been made using experiments from heating. They were using other techniques that might not accurately record the magnetic field. ” .
When lunar samples meet laser beams
Tarduno and his colleagues tested glass samples collected on previous Apollo missions, but they used a carbon dioxide laser to heat the lunar samples for a short period of time, a method that allowed them to avoid them. to alter. Then, they used very sensitive superconducting magnetometers to more precisely measure the magnetic signals of the samples.
“One of the problems with lunar samples is that their magnetic carriers are quite susceptible to change,” says Tarduno. “By laser heating, there is no evidence of a change in our measurements, so we can avoid the problems that scientists may have encountered in the past.”
The researchers determined that the magnetization in the samples could be the result of effects of things like meteorites or comets, rather than the result of the magnetization of the presence of a magnetic shield. Other samples they analyzed had the ability to show strong magnetization in the presence of a magnetic field, but no magnetization, indicating that the Moon never had an elongated magnetic shield.
Tarduno notes: “If there was a magnetic field on the Moon, the samples we studied must have acquired magnetization, but they did not. It is very important that the Moon does not have a field. dynamo (the mechanism by which a celestial body such as the Earth or a star can generate a magnetic field over the long term.
No magnetic shield means plenty of items
Without the protection of a magnetic shield, the Moon was vulnerable to the solar wind, which could have caused a variety of volatile substances, elements and chemicals to become implanted in the lunar soil that can easily evaporate. These volatiles can include carbon, hydrogen, water, and helium-3, an isotope of helium that is not abundant on Earth.
“Our data suggests we should look upward at the helium-3 estimate as the lack of a magnetic shield means more solar winds are reaching the lunar surface, leading to much helium-3 reservoirs. deeper than previously thought, ”Tarduno said. said.
The research could help shed light on a new wave of lunar experiences based on the data collected by the Artemis mission. Data from samples collected during the mission will allow scientists and engineers to study the presence of volatiles and determine if these materials can be best extracted for human use.
The lack of magnetic shielding also means that the ancient lunar soil can keep records of solar wind emissions in the past. Thus, the analysis of soil samples can allow scientists to better understand the evolution of the Sun.
“With the background provided by our research, scientists can more appropriately envision the next round of lunar experiments to be performed,” says Tarduno. “These experiments can focus on current lunar resources and how we can use them, as well as the historical record of what is trapped in lunar soil.”
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