I never expected that I would feel sleepy as soon as I got to work. Is it really the sun's fault?

Review expert: Ye Haiying, deputy director of the New Media Center of the Meteorological Publicity and Science Popularization Center of the China Meteorological Administration (China Meteorological News Agency)

Recently, according to the forecast of the National Space Weather Monitoring and Early Warning Center, geomagnetic activities may occur on the 10th and 11th, of which a moderate or above geomagnetic storm may occur on the 11th, and the geomagnetic activities are expected to continue until the 11th or even the 12th. "Solar flare" has also become the most discussed word on the Internet, and has been on the hot search many times, and the discussion on Weibo has exceeded 500 million times.

What exactly are solar flares and geomagnetic storms? Why do they happen? This all starts with solar activity...

What is solar activity

Solar activity is a general term for all the active phenomena in the solar atmosphere, including sunspots, luminous spots, spectral spots, flares, prominences and coronal transient events .

It is caused by electromagnetic processes in the solar atmosphere. It is sometimes strong and sometimes weak, with an average cycle of 11 to 22 years. The sun in a period of intense activity (called "disturbed sun") radiates a large amount of ultraviolet rays, x-rays, particle streams and strong radio waves, which often cause auroras, magnetic storms and ionospheric disturbances on the earth. Solar activity mainly affects communication and navigation systems.

It can be seen that solar flares are a type of solar activity, and although geomagnetic storms are not solar activities, they are also a "chain reaction" caused by solar activity.

About Solar Flares

The National Space Weather Monitoring and Early Warning Center issued a solar flare information reminder: At 17:13 Beijing time on May 9, 2024, the sun erupted a strong flare (X2.2 level)

Warning screenshot source: National Space Weather Monitoring and Early Warning Center official Weibo

The sun has erupted several times this month. Three strong flares occurred on May 5 and 6, Beijing time, with a magnitude of x4.5, which are large flares.

What is a solar flare

Solar flares are the most violent solar activity . They are generally believed to occur in the chromosphere, so they are also called "chromospheric eruptions". Their main observational characteristics are that bright spots suddenly appear and develop rapidly on the solar disk, with a lifespan of only a few minutes to tens of minutes, and the brightness rises quickly and falls slowly, especially when flares appear frequently and become stronger.

Solar flare Source: China Social Sciences Network

Although the lifespan of a solar flare is only between a few minutes and tens of minutes, the energy released is equivalent to the total energy of one hundred thousand or even one million strong volcanic eruptions, or the explosion of tens of billions of 100-ton hydrogen bombs.

Source: CCTV News

Solar flares, as intense energy eruptions on the surface of the sun, are divided into five levels: A, B, C, M, and X, with A being the lowest energy level and X being the highest energy level.

But don't worry, the sun's temper also has a cycle. On average, every 11 years, solar activity will show a cyclical change from weak to strong and then from strong to weak. This is the solar activity cycle. We are currently in the 25th solar activity cycle, and the sun will reach the peak of the current activity cycle in 2024.

What do solar flares affect?

Although flares are a type of solar activity and the sun is very far away from the earth, flares are like the sun sneezing, and the earth may also catch a cold.

The harm caused by solar flare to the Earth usually depends on the level, duration and energy released of the flare. Generally speaking, X-class is the strongest flare level, which has the potential to have a significant impact on the Earth and may cause "space weather disasters."

Solar flare eruption Source: CCTV-1

These disasters are mainly emitted by the sun in the form of radiation and high-energy matter, affecting near-Earth space and artificial facilities on the ground . For example, solar flares can affect the Earth's ionosphere on the sunward side, disrupting shortwave communications, navigation positioning, maritime search and rescue, some emergency communications, and even mobile phone communications; long-distance high-voltage power transmission systems and oil pipelines on the ground can also be affected.

Does it affect astronauts?

The Shenzhou 18 manned spacecraft was successfully launched on the evening of April 25. The astronaut crew members Ye Guangfu, Li Cong and Li Guangsu who will carry out the Shenzhou 18 manned flight mission have just embarked on their "space journey". Will they be affected?

Xie Lun, an associate professor at the Institute of Space Science and Technology of Peking University, said, "The high-energy particles and radiation released by solar flares may penetrate the protective layer of the space station, increasing the risk of astronauts being exposed to radiation to a certain extent."

However, everyone can rest assured that the safety of astronauts is not without guarantee. Sheron told the Chao News reporter that "they may need to wear special protective clothing to reduce radiation exposure, or move to radiation shelter areas inside the space station, which are usually located in the core of the space station and have thicker radiation shielding."

What do we do on Earth?

We are currently in the rising phase of the 25th solar activity cycle. It is expected that solar activity will gradually increase, and the number of solar flares and coronal mass ejections will increase. However, there is no need to worry too much. The Earth has its own "gas mask" - the magnetic field , which helps us block most of the high-energy particle flow brought by solar eruptions.

In addition, scientific researchers will use various solar observation equipment to track the explosive activities of the solar atmosphere in a timely manner and make space weather forecasts and warnings. During special periods, they can selectively shut down power grids and promptly adjust communication systems, aircraft routes or satellite orbits to minimize the impact of solar activity.

About geomagnetic storms

Does the name "geomagnetic storm" sound familiar to you? A geomagnetic storm is a global and violent disturbance of the Earth's magnetic field. When charged particles in a solar storm impact the Earth's magnetic field, the intensity and direction of the Earth's magnetic field will change drastically and irregularly.

How are geomagnetic storms formed?

We introduced solar activity earlier. When there is solar activity, it is possible to eject hundreds of millions of tons of solar material at a time at a high speed of hundreds of kilometers per second, forming a solar storm .

No life can survive under this large wave of high-energy particles, electromagnetic radiation and other solar materials bombardment. But the reason why the earth can "survive" is because the earth has its own magnetic field.

When the solar storm hits the Earth's magnetic field, the magnetic circle also deforms. Some charged particles enter the atmosphere through the "openings" of the magnetic field at the Earth's poles, which will stimulate the brilliant aurora.

Source: China Science Expo

Generally, after a solar eruption, electromagnetic radiation will reach the Earth in about 8 minutes, and then a large number of charged particles will reach the Earth in as fast as tens of minutes. This is the second round of impact. Finally, the coronal mass ejection will arrive in a few days, which may cause the Earth's magnetic field to change dramatically in a short period of time. If the change in the Earth's magnetic field exceeds a certain value, it is a geomagnetic storm.

Geomagnetic storms are classified into small geomagnetic storms, large geomagnetic storms and extremely large geomagnetic storms according to their intensity.

Space weather level correspondence table source: China Weather Network

As mentioned earlier, approximately every 11 years, solar activity will go from a peak to a trough and then return to a peak. This year is a year of high solar activity. Recently, there have been continuous solar eruptions, which are basically solar flares. According to forecasts, a moderate or above geomagnetic storm may occur on the 11th.

What impact do geomagnetic storms have ? To put it in one sentence, the direct impact of geomagnetic storms on the human body is basically no impact .

Generally, geomagnetic storms do not last too long. Moreover, geomagnetic storms are "sharp and irregular changes in the intensity and direction of the Earth's magnetic field in a short period of time", which does not mean that the magnetic field has lost its function.

The coronagraph carried by the SOHO satellite captured the process of coronal mass ejection. Source: National Space Weather Monitoring and Early Warning Center of China Meteorological Administration

However, it will have a certain impact on aerospace vehicles, such as various satellites, mainly affecting communications and navigation. If the geomagnetic storm is severe, aircraft and ships that rely on instruments, radio communications, and GPS navigation may also be affected. You can rest assured that these impacts are also measurable and controllable .

This year happens to be a year of high solar activity, so we on Earth don't need to worry too much. So far, there has been no research proving that solar activity will have a direct and significant impact on the human body . As for whether solar activity will make people sleepy, there is currently not enough research to prove this statement.

We just need to keep calm and live happily every day!