Are there natural disasters in the universe? The Sun: Look at me, I'm awesome!

With the start of a new solar activity cycle, the space environment may have many uncertain effects on human space activities, leading to space natural disasters. Space natural disasters mainly refer to dangerous behaviors and catastrophic consequences caused by unstable cosmic environment, such as space disaster weather, falling space objects, and harmful fluctuations in the solar magnetic field. Human space activities need to guard against the impact of space natural disasters.

Temperamental space weather

The concept of space weather was first proposed by the United States in the 1990s. It can be understood as the transmission and transformation process of electromagnetic radiation and particle emissions released by solar activity in the Sun-Earth space. Among them, the space area from 20 to 30 kilometers above the surface to the outer atmosphere of the sun is called the Sun-Earth space, which mainly covers the middle and upper atmosphere, ionosphere, magnetosphere, interplanetary and solar atmosphere. When solar activity is relatively stable, it can be called "good weather"; when solar activity is relatively frequent, it may even cause failures or collapses of systems such as radio communications, satellite navigation and electricity, which will be called "bad weather". However, unlike tropospheric weather such as wind, clouds, rain and snow, the frequency of disastrous space weather is not high and is mainly caused by solar activity.

The sun is a ball of hot gas (plasma to be precise) with a temperature of up to one million degrees. It is always "turbulent", especially in the "storm" areas related to sunspots (professionally called solar active regions). It often releases electromagnetic radiation or high-energy particles in an "explosive" manner. This is the "solar storm" that has been frequently seen in the media recently.

A solar storm is a strong disturbance caused by the violent eruption of the sun. Solar eruption activity refers to the short-lived, large-scale energy release phenomenon in the solar atmosphere, which is mainly released in three forms: enhanced electromagnetic radiation, high-energy charged particle flow, and plasma cloud. As solar eruptions intensify, the ejected matter and energy will reach near-Earth space, causing a series of strong disturbances in the Earth's space environment, which will in turn affect human activities.

Solar Storm

During a strong solar storm, there are usually multiple solar flares and coronal mass ejections. The former will release high-energy electromagnetic radiation, which can reach the earth in about 8 minutes at the speed of light, while the latter will release sub-light-speed high-energy particle streams, which can reach the vicinity of the earth in as fast as tens of minutes or as slow as 1 to 3 days.

Solar storms blow the magnetosphere formed by the Earth's magnetic field

Since Galileo invented the telescope, humans have been monitoring solar activity for about 400 years. With the development of science and technology, space-based solar observation capabilities have been significantly improved. For example, the Solar and Solar Wind Observer (SOHO) jointly launched by NASA and ESA can monitor sunspot activity, solar wind, and changes in the internal structure of the sun in real time. Recently, ESA announced that it will launch the Lagrange Project, intending to carry out solar monitoring activities at the Lagrange L5 point, which has never been tried before, and it is expected to establish a relevant early warning mechanism around 2025. The plan will focus on solar storms, effectively predict the solar storm outbreak cycle, and minimize the negative impact on the earth.

Solar wind probe

ESA Lagrange Project L5 Observation Site

Academics usually use the relative number of sunspots to characterize the long-term level of solar activity, and take 1755, when the number of sunspots was the lowest, as the first solar activity cycle. In solar activity, the cycle changes sometimes last as long as 11 years, but sometimes they are as short as a few minutes. At present, solar activity has entered the end of the 24th activity cycle, and the 25th activity cycle is expected to begin around January 2020 and end around June 2031. During this period, the level of solar activity is low, and the solar wind speed will also be at a low level, so the recent solar activity is relatively stable.

Solar storms have serious impacts on human activities

Solar storms pose many threats and hazards to human life. The famous "Quebec Incident" in history is one example. In 1989, the sunspot number peaked in the 22nd solar activity cycle. In just one month, solar storms produced about 107 solar X-ray flares and dozens of coronal mass ejections. The "sweep" of the solar storm caused many major power system failures. Most areas of Quebec, Canada, were without power for more than 9 hours, and the lives of 6 million residents were seriously affected. Strong solar flares caused 39 sudden disturbances in strong shortwave communications, including 15 partial interruptions and 24 complete interruptions.

A transformer burned out during the Quebec blackout

The large magnetic storms generated by solar storms have also caused many spacecraft failures. There have been 46 records of satellite anomalies. For example, the large magnetic storm caused the interruption of signals from the US National Weather Satellite, and also caused a series of navigation satellites to be unable to operate normally for a long time, forcing thousands of air targets tracked by the military system to be repositioned.

Impact of solar storms on spacecraft

According to incomplete statistics, there are several to more than ten disastrous space weather events similar to the "Quebec event" in each solar activity cycle. Another example is the "Halloween event" (named after Halloween in the West) that occurred in the 23rd solar activity cycle, which caused global shortwave communications to be interrupted and civil aviation communications to fail; the observation equipment on NASA's Mars exploration satellite Odyssey was completely destroyed by particle radiation; and the shortwave signals of radio observation points in Beijing, Manchuria and other regions of my country were also interrupted for a time.

The raging solar storm

With the rapid development of modern aerospace technology, the equipment systems and information systems based on space platforms are increasingly used in space activities. As a result, the impact of space weather on space activities continues to expand and the degree of impact continues to deepen. Solar storms have important impacts on the following aspects:

Impact on space activities. High-energy charged particles ejected by solar storms can continuously hit the surface of spacecraft and cause radiation damage to spacecraft. At the same time, a large number of high-energy electrons will also pass through electronic devices, seriously affecting the instructions and data images issued by the instruments. According to analysis, when a spacecraft is sailing in deep space or astronauts are working outside the cabin, there is about a one in ten probability of being exposed to a lethal dose of high-energy charged particle radiation, which shows the harm it causes to space activities.

It will have an impact on communications, early warning, navigation and positioning. With the outbreak of solar storms, the available frequency bands of shortwave radio communications and early warning radars will become narrower due to sudden disturbances in the ionosphere, and satellite microwave communications will also reduce communication quality or even signal interruption due to ionospheric flickering; GPS satellite navigation and positioning errors will increase to tens to hundreds of meters due to ionospheric storms.

Affects the operation of spacecraft in orbit. Solar storms cause severe disturbances in the density of the upper atmosphere, and the actual orbit of the spacecraft will deviate seriously from the predicted orbit, so that the ground tracking station will "lose" the tracking target.

Actively prevent and effectively resolve the "solar crisis"

As long as proactive preventive measures are taken, the harm caused by space weather can be avoided.

Monitoring and forecasting. Strengthen the monitoring and forecasting of space disaster weather, develop monitoring and forecasting means, and establish a disaster weather forecasting mechanism. For example, establish space weather detection stations at the Sun-Earth Lagrange point, conduct long-term space environment monitoring in low and high orbits, establish ground monitoring and management agencies, and form a monitoring and forecasting system for space disaster weather and a monitoring and forecasting mechanism.

Mechanism research. Based on space disaster monitoring data, conduct weather environment research to improve the level of understanding of space weather; conduct research on the impact of disaster weather on space activities, and study the impact mechanism of the space environment on spacecraft; conduct research on the impact mechanism of space weather on the Earth environment such as atmospheric density and the Earth's magnetic field.

Emphasis on protection. Based on the current level of understanding, comprehensive consideration of technical difficulties and costs should be given to studying the avoidance measures of space safety equipment against disastrous weather, and appropriately improving the protection capabilities of space safety equipment.

Technological innovation. Carry out technological innovation in response to and prevention of space disaster weather, explore new space communication methods such as laser communication, and reduce the impact of disaster weather on space-based communications.