New discovery: safe exploration of the moon, the Earth’s magnetic field this “umbrella” is not very reliable.

With the successful launch of “TianQ 1”, China’s exploration of Mars was officially launched, triggering heated discussion among netizens, one of the enduring topics is immigration to Mars. But apart from the earth, there is only one moon that humans have ever stepped foot on. The moon seems to be more at its fingertips than Mars.

Recently, Shandong University’s space science team, a joint domestic and foreign researchers, discovered a new model of the moon’s exposure to solar radiation — the moon during full moon may be free from the protection of the Earth’s magnetic field, exposed to high-energy solar particles radiation risk. The paper appears in Geophysical Research, Space Physics.

“The swaying of the Earth’s magnetic tail is a phenomenon of interaction between the solar wind and the Earth’s magnetosphere. Because this wobble affects the moon’s space environment, the study will help people understand what different space weather may be faced during long-term lunar landings. Shi Quanqi, a professor at Shandong University’s School of Space Science and Physics, told Science and Technology Daily that it was thought that the Earth’s magnetosphere deflection occurred mainly far from Earth, and this was the first time that such deflection had occurred in lunar orbit.

High-energy particles affect lunar exploration activity.

A round of full moon, as a mirror, the world’s years quiet. However, the surface of the moon without an atmosphere is far from “quiet” and is even “bombarded” by high-energy particle radiation, as the solar wind keeps blowing into interplanetary space, or with the sun erupting.

What impact will such a “bombardment” have on the moon landing?

“The most dangerous thing about lunar exploration is the effect of high-energy particles on equipment materials and devices.” Shi Quanqi said. The bombardment of high-energy particles can cause varying degrees of damage to electronic devices and satellite materials, such as increased instrument noise, incorrect sensor readings, and degradation of solar panels. Satellites orbiting the moon can also be affected by charged particles and accumulate over time, causing equipment to be “decommissioned” earlier. In addition, human cells can become cancerous if they are exposed to radiation doses that exceed safety standards for a longer period of time. So for astronauts working on the moon, excessive radiation can affect physical health and even endanger lives.

Previous studies have shown that water is produced when solar wind protons react with lunar soil, so understanding the laws of solar radiation on the lunar surface could help to better understand where and how water is deposited on the lunar surface for daily consumption of lunar operations and as a source of spacecraft fuel.

When the moon turns to the side far from the sun, the Earth’s magnetic field has a protective effect on it. Studies have shown that the Earth’s magnetic field can be elongated at night to form a magnetic tail that deflects high-energy particles from the solar wind and gives the moon a “shield.”

In other words, protons, electrons, etc. in the solar wind will reach the moon’s surface for three-quarters of the moon’s transit cycle, as if a “storm” would hit the moon’s surface;

Previous observations and simulations have shown that spacecraft operating in lunar orbit and astronauts operating on the moon will be relatively safe during the full moon due to the protection of the Earth’s magnetosphere.

Thus, if the space weather can be as distinct as the Earth, then human activity on the moon will have a clear “safe period”. However, the Team’s findings suggest that this is not the case, and that the previously thought of a “safe period” can also be a big risk.

The solar wind causes the “umbrella” to sway.

On March 8, 2012, an interplanetary shock wave struck the moon, and the Altrum is orbiting the moon, carrying a magnetometer that detects the plasma velocity of the satellite’s location in space and the size and direction of the magnetic field, and transmits data back to Earth.

The researchers found that as interplanetary shockwaves passed, the solar wind swerved dramatically, causing the magnetosphere to deflect significantly in the moon’s orbit: the tail swayed like a wind-blown “wind bag.”

Such swings cause the moon’s space weather to “change face”: the moon during the full moon is directly exposed to the Earth’s magnetoscoe (heated and compressed solar wind). If there is detection activity on the moon’s surface at this point, and astronauts and base facilities are not effectively protected, they could still be attacked by solar high-energy particles, even with the protection of the Earth’s magnetosphere. It’s like in a storm, people will still be caught in the rain even if they stand under an umbrella.

The team of Shi Quanqi of Shandong University, in cooperation with Tang Binbin, an associate researcher at the National Center for Space Science, made a more detailed exploration of the “face-changing” causes of lunar space weather through observation and simulation, with the support of the opening of the National Key Laboratory for Space Weather.

Tang Binbin introduced, one of the advantages of simulation is that the magnetic field and plasma activity of the Earth and moon space can be reproduced as a whole, overcoming the limitations of the satellite can only observe one or two points;

“Because it is not clear whether the Earth’s magnetosphere deflection is a dominant role in the earth’s magnetosphere deflection, we have done several simulations by changing the input conditions. For example, in a simulation, we let the interplanetary shock wave hit the Earth head-on, only to cause the direction of the solar wind to mutate, and found that the magnetosphere can have the same deflection. Shi Quanqi said that the solar wind itself can contribute to the Earth’s magnetic field deflection, meaning that this deflection may occur more frequently than originally thought, because the probability of solar wind meeting the deflection conditions is much higher than the probability of interplanetary shock waves.

“We also validated the results with another model. Two different global magnetic fluid simulations show that the magnetic tail deflection at the lunar position is mainly controlled by the solar wind, with a time scale of about half an hour. Mr Shi said.

The new discovery will help the moon space weather forecast.

If the phenomenon of the Earth “unable to cover” the moon is regular, then the lunar space weather will hopefully be forecasted and early warning.

“Basic theoretical studies will model based on the observations and numerical simulations of the data, ” Shi explained. In the future, this deflection can be monitored by satellites closer to the sun. Once the deflection occurs, the signal can be transmitted to the ground immediately, and people can follow the model analysis to predict how far the magnetosphere will be deflected when it reaches the moon. If the deflection is severe, early warning can be made dozens of minutes in advance, the moon’s facilities can be shut down sensitive instruments, and the astronauts immediately hide in the shelter. “

“We expect this discovery to help improve the dynamic model of the lunar radiation environment and provide a safe buffer period for all activities on the moon.” Shi Quanqi further said.

“The early warning of space weather is much like the weather forecast on Earth, except that the observations require space weather to track the impact of solar wind, particle storms, and interplanetary electromagnetic fields on space.” Shi Quanqi said that Shandong University has now set up a lunar radiation detection laboratory, in addition to further analysis of China’s Chang’e-4 probe transmitted back to the lunar space environment data, will also develop a number of autonomous detection methods, hoping to study the relevant space weather activity law more clearly.

Source: Science and Technology Daily.

Editor: Zhang Shuang.

Audit: Tube Jingjing.

Final: Cold Wensheng.