Sunspot is a kind of solar activity on the photosphere, and it is the most basic and obvious phenomenon in solar activity. It is generally believed that sunspots are actually a huge vortex of hot gas on the surface of the sun, with a temperature of about 4500 degrees Celsius. It looks like some black spots because it is lower than the surface temperature of the photosphere of the sun. Sunspots rarely move alone. Often appear in groups.
Sunspots are composed of umbra and penumbra, and umbra is a particularly dark part. Penumbra is not too dark, but it is composed of many fiber textures and has a spiral structure. When the large sunspot group appears vortex structure, it indicates that the sun will change dramatically. People have discovered sunspot activity for thousands of years. The sunspot activity cycle is 1 1.2 years. At that time, it will cause damage to the earth's magnetic field and various electronic products and appliances. In the first four years or so, sunspots were constantly produced and increased, and their activities intensified. The year when the number of sunspots reaches the maximum is called the peak of solar activity. In the next seven years, sunspot activity gradually weakened and the number of sunspots became less and less. A year with very few sunspots is called solar activity valley year. According to international regulations, the sunspot cycle starts from 1755 and is the first week, and then it is arranged in turn. 1999 is the 23rd week.
solar flare
On September 1859 and 1 day, two British astronomers observed the sun with a high-powered telescope. At the same time, near a large group of sunspots with complex shapes, they saw a large bright flash with dazzling light. This piece of light passed over the sunspot group, and its brightness gradually weakened until it disappeared. This is the most intense activity phenomenon on solar flares. Because this kind of flare is particularly powerful, it can also be seen under white light, so it is also called "white light flare". White light flare is extremely rare, and it is only possible to appear at the peak of solar activity. Flares generally only exist for a few minutes, and individual flares can last for several hours. Flares release a lot of energy when they appear. The total energy released by a large flare is as high as 1026 Joule, which is equivalent to the total energy of 1000 trillion megaton hydrogen bomb. Flares first broke out in the lower corona and then descended to chromosphere. What was observed with chromosphere telescope was the subsequent flare, or secondary flare.
Flares are divided into four grades according to the area, which gradually increase from 1 to 4, and those less than 1 are called sub-flares. The remarkable feature of flare is that there are many kinds of radiation, not only visible light, but also radio waves, ultraviolet rays, infrared rays, X rays, gamma rays and so on. A large number of ultraviolet rays and X-rays radiated by flares will seriously interfere with the absorption and reflection of radio waves by the ionosphere, so that short-wave radio waves are partially or completely absorbed, and the short-wave is weak or even completely interrupted.
[Edit this paragraph] Sunspot characteristics
Charged ions produced by sunspots can destroy the ionosphere in the upper atmosphere of the earth, make the atmosphere abnormal, interfere with the earth's magnetic field, and thus interrupt telecommunications.
A well-developed sunspot consists of a darker core and a brighter part around it, with a depression of about 500 kilometers in the middle. Sunspots often appear in pairs or groups, and most of them are composed of two main sunspots. Those located in the west are called "leading sunspots" and those located in the east are called "following sunspots". A small sunspot is about 1000 km, and a large sunspot can reach 200000km.
The formation of sunspots is closely related to the solar magnetic field. But how did he form? Astronomers have not found the exact answer to this question. However, scientists speculate that it is very likely that the strong magnetic field has changed the material structure of a certain area, making the light and heat inside the sun unable to reach the surface effectively, forming such a "low temperature zone". The more sunspots there are, the older the sun may be (in recent years, it has been found that sunspots on red dwarfs occupy half of the surface, see the third issue of China in 2005), or it may be a common feature of the life span of all stars. Sunspots may be nuclear waste from the sun (such as nuclear waste from human nuclear reactors). It happens about once a year 1 1, which may be that sunspots turn up and down inside and on the surface of the sun (for example, Yuanxiao is cooked up and down in a pot). The low temperature of sunspots should also be a proof of wasting materials (for example, charcoal ash in a coal stove generally cannot produce high temperature), and the temperature around sunspots should be higher than that in the normal place of the sun (the reason for this change). Due to the low density and rotation of the sun, sunspots move to low latitudes. Just as the continental plate on the earth moves to low latitudes, there is a depression of 500 kilometers where there are sunspots, which may be the reason why the temperature is low and it no longer expands. In addition, it is particularly important that sunspots affect the magnetic field, not the magnetic field.
Observe history
The earliest record of sunspots in the world was in Huainanzi written by China around 140 BC. The records of sunspots in the first 28 years are more detailed in Records of the Five Elements in Hanshu.
1840s, an amateur astronomer in Germany discovered the periodic variation law of sunspot10-1year. Through long-term observation, it is also found that the latitude distribution of sunspot activity on the solar surface changes with time. At first, almost all sunspots were distributed at a latitude of 30. When the solar activity is intense, it often appears in 15, gradually moves to the low latitude area and disappears at 8 o'clock. When the sunspot in the last cycle has not completely disappeared, the sunspot in the next cycle will appear near 30 north latitude. If the latitude of sunspots is taken as the ordinate and time as the abscissa, then the distribution map of sunspots is very similar to that of butterflies, so it is called butterfly map. Many experts have studied the meaning of butterfly diagram, but until now there is no clear conclusion.
The periodicity of sunspots
Astronomers began to count sunspot activities from 1755, and stipulated that the average activity period of sunspots was 1 1.2 years. The year with the least sunspots is the beginning year of a cycle, which is called the "minimum year of solar activity" and the year with the most sunspots is called the "maximum year of activity".
The influence of sunspots on the earth
The sun is the source of light and heat on the earth, and its every move will have various effects on the earth. Because sunspots are a kind of intense activity phenomenon of matter on the sun, their influence on the earth is obvious.
When there are a large number of sunspots on the sun, the compass on the earth will shake and cannot indicate the direction correctly; Pigeons who are usually good at discerning directions will get lost; Radio communication will also be seriously blocked, or even suddenly interrupted for a period of time. These abnormal phenomena will pose a great threat to the safe navigation of aircraft, ships, satellites and television faxes.
Sunspots can also cause climate change on the earth. /kloc-more than 0/00 years ago, a Swiss astronomer discovered that when there were many sunspots, the climate on the earth was dry and agriculture was bumper; When there are few sunspots, the climate is humid and the rainstorm is disastrous. Zhu Kezhen, a famous scientist in China, also studied that the century when sunspots were recorded in ancient books in China was also a particularly cold century in winter. Some people have counted the changes of rainfall in some areas and found that this change repeats every 1 1 year, which is probably related to the increase or decrease of sunspot number.
Scientists who study earthquakes have found that when the number of sunspots increases, there are more earthquakes on the earth. The number of earthquakes is also about 1 1 year.
Botanists also found that the growth of trees also changes with the 1 1 annual cycle of solar activity. Trees grow fast in years with many sunspots; Years with fewer sunspots grow slowly.
More interestingly, the change of sunspot number will even affect our body, and the change of white blood cell number in human blood has the periodicity of 1 1 year.
Regarding sunspots, China has the earliest observation records in the world. About 140 BC, in the book Huai Nan Zi, there was a description that there was a witch in Japan and China. The earliest sunspot record recognized in the world today is the sunspot that appeared in March of the first year of peace (28 BC) in the Five Elements of Hanshu: "The first year of peace ... March has passed, the sunrise is yellow, and there is black gas as big as money, living in the center of Japan." This record describes the time and location of sunspots in detail and clearly. The earliest chronicle of sunspots in Europe was in August, 807, when it was mistaken for the transit of Mercury. It was not until the Italian astronomer Galileo 1660 invented the astronomical telescope that sunspots really existed. Before that, there was a record of sunspots in 10 1 in Chinese history. These records have not only time, but also shape, size, position and change. No wonder American astronomer Haier praised: "It's amazing that China was so diligent in observing astronomical phenomena in ancient times. They observed sunspots, about 2,000 years earlier than the West, which was recorded endlessly in history and was very correct and credible. "
Why do people get sick easily at the peak of sunspot activity?
As we know, the surface temperature of the sun is different, with high temperature in some places and low temperature in others. When the temperature in the central area of the sun is about 1500 lower than the surrounding area, this area looks darker than the surrounding area, just like a bright circular surface with black spots on it, so people call it "sunspot".
The number of sunspots is sometimes more or less, and its change is very regular, generally every 1 1 year is a cycle. According to the records, during the 803 years from 1 173 to 1976, there were 56 pandemics, all of which occurred in years with high sunspot activity. At the peak of sunspot activity, the number of patients with myocardial infarction also increased sharply.
Why does the number of patients increase at the peak of sunspot activity? It turns out that at the peak of sunspot activity, the sun will emit a large number of high-energy particle streams and X-rays, and cause geomagnetic storms on the earth. They destroy the atmosphere above the earth, make the climate abnormal, and make the microorganisms on the earth multiply, creating conditions for the epidemic of diseases. On the other hand, the frequent activity of sunspots will cause strong ionization of substances in organisms. For example, the sharp increase of ultraviolet rays will cause the variation of genetic factors in the cells of cold virus, resulting in a subtype of influenza virus that is highly contagious but immune to human body. Once the virus spreads through air or water, it will cause a fierce flu.
Scientists have also found that the toxicity of pathogenic bacteria will increase in years when sunspot activity is unusually frequent. After they enter the human body, they can directly affect the physiological and biochemical processes of the human body and also affect the course of disease. Therefore, when the number of sunspots reaches its peak, it is necessary to prevent the epidemic as soon as possible.