The British industrial revolution launched in late 18 and early/09 not only opened the era of large-scale industrial production, but also had a great impetus and far-reaching impact on the scientific exploration in 19. This period produced a series of scientific discoveries closely related to space physics.

Johann Carl Friedrich Gauss is a famous British physicist and mathematician, and is known as the prince of mathematics. He showed superhuman mathematical talent when he was very young. 1833, Gauss proposed the spherical harmonic analysis method, which was named after him. 1837, Gauss invented the double-wire magnetometer to measure the magnetic field. Under the leadership of his organization, a number of geomagnetic stations were observed on the internet. Gauss's analysis of these network observation data makes Gauss think that most of the earth's magnetic field comes from the inside of the earth. Gaussian analysis can distinguish which magnetic field components come from inside the earth (internal field) and which magnetic field components come from outside the earth (external field). This part of the external field, that is, the part of the earth's magnetic field that changes with time, is generated by the current in the atmosphere and the space above the ground, and most of these currents are influenced and controlled by solar activities.

At that time, there was an astronomy enthusiast in Germany, Schwabe. He is a pharmacist by profession, but he loves astronomy. At that time, some people thought that there was a planet inside Mercury that was closer to the sun than Mercury, called Voilguin. The amateur astronomer is obsessed with finding the deepest planet in the legend. However, after searching for more than 20 years, the planet was not found, but the sunspots on the surface of the sun were more "eye-catching". After so many years, Schwabe gradually figured out the law, and unexpectedly found that the number of sunspots had a periodic change of about 1 1 year in 1846.

At that time, Britain, known as the "Imperial Empire", had colonies all over the world, which made it convenient for British Navy Colonel Edward Sabin to conduct networked observation in a wider area. His networked observation of geomagnetic stations even extended to Toronto, Canada. 1852, Sabin found in the data of these geomagnetic stations distributed all over the world that the earth's magnetic field not only changes with day and night, but also hides a longer-term change law, that is, the change law consistent with the sunspot change cycle in Schwabe. Based on this, he speculated that there is an active atmosphere in the outer layer of the sun, and some activities here may have an impact on the earth's magnetic field in a way that will not change the earth's heat supply. Now, what a wonderful prophecy! But this idea was quickly rejected by Lord Kelvin, a British scientist we introduced in Inward Bubble, because Kelvin thought it was just a coincidence in time, and there would be no other material transport between the sun and the earth except light and heat. In the famous Carrington event of 1859, the sun suddenly burst into a flare, and Carrington himself saw the surface of the sun suddenly brighten. About 18 hours later, the high-speed solar wind hit the earth's magnetic field at an amazing speed of 2300 kilometers per second, which not only triggered an aurora burst extending to the middle and low latitudes, but also triggered a violent disturbance of the earth's magnetic field. It was the British physicist Balfour Stewart who recorded this magnetic field disturbance. Two years later, at 186 1 year, the geomagnetic pulsation with a period of several minutes was also found by Stuart in the observation data.

1897, British scientist Thomson Joseph John discovered cathode rays (that is, electrons), which greatly inspired Norwegian scientist birkeland: Aurora may be cathode rays emitted by the sun. In order to prove his idea, during 1897- 1903, he braved the cold and made three geomagnetic field measurements during the aurora in northern Norway. After analyzing these data, birkeland was surprised to find that during the auroral period, significant magnetic field disturbances occurred on the south side and the north side of the auroral region at the same time, and the directions of the disturbances were just opposite, which indicated that a current was flowing horizontally overhead. This horizontal current is the set of polar photoelectric currents. It is impossible to exist in isolation from this horizontal current, and there must be a vertical current along the magnetic field direction connected with this horizontal current, which he calls field current. To further prove his idea, birkeland made a small earth model with magnetized iron balls in the laboratory, called Terrella, which is equivalent to a small magnet in the small earth. He coated the tiny surface of the earth with fluorescent powder and put it in a vacuum-pumped transparent glass jar. When the cathode ray (that is, electron beam) is incident on the small earth model, the cathode ray is guided by the magnetic field, and annular luminescence occurs around the magnetic pole of the small earth, which is very similar to the aurora. On the basis of this experiment, birkeland thought that the charged particles that caused the aurora were cathode rays from the sun. He wrote these results into a paper and submitted it to Nature. The reviewer is Arthur Schuster, a student in Carrington. Schuster retorted: "If the electron flow from the sun causes the aurora, although the aurora does follow the magnetic field, the repulsion between charged particles will make them diverge from each other, instead of gathering together in bundles or pieces like the aurora we see. And if the sun transmits electrons to the earth, the sun will be positively charged and the earth will be negatively charged, but it is not. " Although birkeland pointed out in his defense that the sun emits a stream of neutral particles with positive and negative charges (that is, plasma, that is, solar wind), the article was rejected. Birkeland was hit by this rejection and didn't contribute again. On the contrary, he wrote down his observations, experiments and ideas in the report on aurora exploration. Birkeland's field current was also confirmed by later satellites and named after him.

The magnetosphere of the earth is an invisible bubble blown by the earth's magnetic field in the solar wind, and the prototype of this bubble is the concept of "cavity" proposed by British scientist Sydney Chapman and his graduate student ferraro in 1927 in 1930, which is used to explain the global ground magnetic field disturbance such as magnetic storms. Later, after this concept entered the space age, satellite observations confirmed the existence of this hole. The cause of magnetic storm is that charged particles from the sun enter the area controlled by the earth's magnetic field, which increases the magnetosphere current outside the earth.

Just like a small magnet in our hands, the earth's magnetic field is generally invisible, but the change of the earth's magnetic field sometimes becomes visible and tangible through the shaking or pointing change of the compass. Aurora is the most remarkable luminous phenomenon in space physics, which is accompanied by the disturbance of the earth's magnetic field. This makes people's exploration of geomagnetic phenomena and aurora almost synchronous and gradually interrelated. Just like a happy childhood will be accompanied by growing pains, people's cognitive process of natural phenomena is constantly advancing in the process of questioning and arguing, and even some discoveries are cross-border. As the two main phenomena of space physics, people's observation, exploration and thinking of aurora and geomagnetic phenomena before the space age constitute the childhood of space physics. Even in today's space age, the ground observation of geomagnetic field still plays an irreplaceable role in the study of space physics.

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