The Sun can send out eruptions of energetic particles. Credit: NASA/SDO via AP
NASA has set its eyes on the Moon with the aim of send astronauts back to the lunar surface by 2026 and establishing a long-term presence there by the 2030s. But the Moon isn't exactly a habitable place for people.
Cosmic rays from distant stars and galaxies and solar energy particles from the Sun bombard the surface, and exposure to these particles can pose a risk to human health.
Both galactic cosmics rays and solar energetic particlesThey are high-energy particles that travel near the speed of light.
As galactic cosmic radiation trickles toward the Moon in a relatively constant flow, the energetic particles can They come from the sun in great bursts. These particles can penetrate human flesh and increase the risk of cancer.
The Earth has a magnetic field which provides a shield against high-energy particles from space. But the Moon has no magnetic field, leaving its surface vulnerable to bombardment by these particles.
During a large solar energetic particle event, the radiation dose received by an astronaut inside a spacesuit could exceed 1,000 times the dose that someone on Earth receives. That would exceed what is recommended by an astronaut. lifetime limit for 10 times.
NASA Artemis Programwhich began in 2017, aims to restore human presence on the Moon for the first time since 1972. My colleagues and I at the University of Michigan CLEAR center, the Center for completely clear SEP forecastingare working to predict these particle ejections from the Sun. Forecasting these events can help protect future Artemis crew members.
An 11-year solar cycle
The Moon faces dangerous levels of radiation in 2024 as the Sun approaches its peak. 11 year solar cycle. This cycle is driven by the Sun's magnetic field, whose total strength changes dramatically every 11 years. When the Sun approaches its maximum activity, up to 20 large solar energetic particle events can occur each year.
Both solar flareswhich are sudden eruptions of electromagnetic radiation from the Sun, and coronal mass ejectionswhich are expulsions of a large amount of matter and magnetic fields from the Sun, can produce energetic particles.
https://www.youtube.com/embed/w6C1_Qci8nQ?wmode=transparent&start=0
The Sun is expected to reach its solar maximum in 2026, the planned launch date of the Artemis III mission, which will take a crew of astronauts to the surface of the Moon.
While researchers can track the Sun's cycle and predict trends, it is difficult to guess when exactly each solar energetic particle event will occur and how intense each event will be. Future astronauts on the Moon will need a warning system that more accurately predicts these events before they happen.
Solar Event Prediction
In 2023, NASA funded a five-year space weather center of excellence. called CLEARwhose objective is to forecast the probability and intensity of solar energetic particle events.
Right now, forecasters at the National Oceanic and Atmospheric Administration Space Weather Prediction Center, the center that tracks solar events, cannot issue a warning about an incoming solar energetic particle event until they actually detect a solar flare or coronal mass ejection. They detect them by observing the Sun's atmosphere and measuring the X-rays that flow from the Sun.
Once a forecaster detects a solar flare or coronal mass ejection, the high-energy particles typically reach Earth in less than an hour. But astronauts on the Moon's surface would need more time to seek shelter. My team at CLEAR wants to predict solar flares and coronal mass ejections before they happen.
While scientists don't fully understand what causes these solar events, they do know that the Sun's magnetic field is one of the key drivers. Specifically, they are studying the strength and complexity of the magnetic field in certain regions on the surface of the Sun.
At the CLEAR center, we will monitor the Sun's magnetic field using measurements from ground- and space-based telescopes and build machine learning models that predict solar events, hopefully more than 24 hours before they occur.
Using the forecasting framework developed in CLEAR, we also hope to predict when the particle flux falls back to a safe level. That way, we will be able to tell astronauts when it is safe to leave their shelter and continue their work on the lunar surface.
Lulu ZhaoAssistant Research Scientist in Climate and Space Engineering and Sciences, University of Michigan
This article is republished from The conversation under a Creative Commons license. Read the Original article.
