Sunspot news and history

Do you know that the change in the number of black spots on the sun, called sunspots, seriously matters to Earth? Its cycle regularly changes every 11 years and CNN, NASA and other experts say now is the time for the decrease in the number of sunspot. These changes somehow matter to Earth and all the creatures living on Earth. The fun fact is that this is not only on recent phenomena, but old historical books also had described these changes. For example, the oldest known sunspot observation record is a Chinese observation record made in 28 BC. In Korea, the historical records of the Samguk Sagi (the history of the three Korean ancient kingdoms) show the observation of black spots, and very clear records of black spots are also found in the Goryeo history (the history of Korean dynasty) and the Jeungbo (the book of agricultural methods of Joseon dynasty) literary manuscript. The interesting point is that they classified sunspots into five levels by its size. Not only oriental historical books mentioned this black spot, but also scientists in Europe observed and were interested in changes of sunspots. For example, Galileo Galilei described and drew what a sunspot looks like and how it moves in the 17th century. As these evidences show, we can know sunspots have been the object of attention for a long time.

Then what are sunspots and why does it matter so much to humans?

To understand why it is important to know the cycle and principle of sunspots, you should first know what exactly the sunspot is. A sunspot is a black spot we can observe on the surface of the sun. It indicates places where magnetic fluctuations inside the sun are exposed to the surface and where a large number of strong magnetic forces are gathered. These spots are made by poor convection heat transfer due to strong magnetic forces. Due to poor heat transfer, the temperature is about 2,000℃ lower than the surrounding area, which is why the sunspots look dark from Earth. The more there are darker spots in the sun, the more active the sun is. When the number of sunspots increase, the energy of the sun gets extremely powerful and explodes. When the number of sunspots decrease, the energy of the sun gets lower and become less active. To put it simply, sunspots are the points where the sun’s magnetic field energy is concentrated and making the power base for sun storm.

When the number of sunspots gets to a maximum, it is called solar maximum, and if it reaches a minimum, it is called solar minimum. Experts of the solar system are predicting now it is moving on to a period of solar minimum. The reason they said this is because recently, sunspots were unobservable for over 100 day. Last year was less; sunspots weren’t observable for 281 days. As the number of sunspots changes, it also brings changes to Earth. If it increases, solar wind gets stronger and flares of the sun become bigger and more powerful. The flare seriously matters to Earth because it affects satellites which are circling Earth and all the electronic devices on Earth. When the sunspots increase, these black spots explode and solar storms occur when high-energy plasma particles from the surface are released into space. At this point, powerful light energy is released, and plasma particles fly at the speed of light at 300,000 kilometers per second, affecting the ionosphere of Earth. The ionosphere is a layer that helps wireless communication by reflecting radio waves, and if there is a problem here, Earth's radio communication can be disrupted. This can cause problems in navigation, disconnection of cell phones, and many other fatal problems. Modern society cannot live without electricity, so it might cause confusion and inconvenience to us. In the event of a severe solar storm, particles with enormous energy collide with Earth's magnetic field, causing geomagnetic storms that could cause a ‘blackout’ in the worst case scenario. On the contrary, based on what Earth is experiencing now, some scientists say it would be similar to the Dalton Solar Minimum and the Carrington Event after this solar minimum. Dalton Solar Minimum took place between 1790~1830. During this time, extreme cold, crop loss, famine, and powerful volcanic eruptions occurred all over the planet. The temperature went down to 2℃ during these 20 years. Also, due to harsh weather, there was not much crop to be harvested, so food and grain prices soared, and the overall food production around the world decreased, leading to a famine especially in Europe. In particular, Europe’s temperature dropped and this caused the Thames to freeze. Also, earthquakes and tsunamis occurred several times around the world, killing tons of people. Ponds and lakes froze even in July and August. In Indonesia, Mount Tambora erupted. This second-largest volcanic eruption in 2,000 years killed about 71,000 people.

The Carrington Event happened when sunspots increased more and more right after the number of sunspots reached solar minimum. The greatest solar storm in history happened in 1859. At that time, the aurora of the Mt. Rocky was so bright that miners there were confused about whether it was morning and started to prepare their breakfast. People living in the North-East part of America could even read a newspaper at night due to this light. The incident paralyzed the entire 225,000km network. In 2011, National Security Agency (NSA) made an announcement that if the incident like the Carrington Event happens again, its damage amount will be around one to two trillion dollars and will take four to 10 years to restore it.

Prevent Earth from the Danger of the Sun Storm!

Then how should we predict the cycle of sunspot or how can we prevent solar storms? With the level of technology now, humans cannot exactly know when or why the number of sunspots changes. However, in 2018, NASA sent a solar probe called Parker Solar Probe (PSP) to research the activity of the sun. In addition, in 2020, NASA has sent another solar probe called Obiter Solar Probe (OSP) to research the sun’s magnetic pole. They were both sent for deeper research to get a better understanding. Researching the north pole and the south pole of the sun is very important because scientists are thinking that the change of the number of sunspots is strongly related to the activity of the sun’s rotation. Thus, scientists are expecting them to take the veil off of the secret of the sun by circling its orbit. Also, we can expect collaboration with Solar Probe Parker and Solar Probe Obiter. For example, if PSP is closer to the sun, then it observes particles that came from the sun closely and OSP can examine them from a long distance, complementing each other.

Some experts are very concerned because it is similar to the last time when the numbers of sunspots were the lowest in the 17th-century, when the world had been oddly cold at that time. Therefore, experts think it might cause the same problems this time. Consequently, the British research team warned that there are possibilities that serious cold will come years later after 2015. As mentioned before, experts are predicting solar minimum by observing decreases of sunspots these days.

Sim Jun-sung