A recently published article used photographs taken by the astronomer in 1607 Johannes Kepler (1571-1630) to better understand the dynamics and documentation solar cycles. The conclusion, which calls into question an assumption made by other scientists before, is still not certain – only the Kepler records analyzed in the study are enough.
From time to time, the Sol undergoes changes in its level of activity. Such changes usually occur every 11 years, going from what experts say is a minimum to a maximum and then back to the minimum – these dynamics including solar cycles.
In such changes, sunspots appear in different places on the surface of the star. At the beginning of a cycle, for example, these spots tend to be identified in the highest latitudes of the Sun, moving later to the more central regions of the star.
Hisashi Hayakawa, from the Space-Earth Environment Research Institute at Nagoya University in Japan, explains that these spots mainly offer information about the Sun “However, solar activity can also affect terrestrial environments”, said Hayakawa, who is one of the authors of the article recently published in the scientific journal The Astrophysical Journal Letters.
What Hayakawa and other researchers who signed the text defend is that the charts made by Kepler, one of the most important names in science, were of sunspots. It was only possible to make pictures like this by using the camera obscura technique.
Hayakawa explains that this method consists of “a hole and a dark room for projecting external images, including the solar disk. ” Although it makes it possible to see the surface of the sun, the camera is not the most recommended alternative for this. “They have trouble capturing smaller sunspots compared to telescopes,” Hayakawa continued.
Nevertheless, the researchers used Kepler’s pictures and also mathematical calculations to estimate the position on the sun’s surface of the spots recorded by the scientist. The conclusion was that these spots were not found in the highest latitudes of the Sun, which is a sign that they correspond to the end of the solar cycle.
Therefore, the authors argue that Kepler’s pictures in 1607 may be due to the end of a solar cycle called -14. On the other hand, records from 1610 show sunspots at higher latitudes, an indication that it would be the beginning of another solar cycle – in this case, named -13.
The conclusion of the study is important because there was no evidence of solar cycle -14. Therefore, experts believed that the cycle number -13 showed an irregularity in time, which does not correspond to the average level of 11 years. In the research, the authors reject this point, arguing that “the sun was doing its daily work, and not something special”, summarizes Hayakawa.
The results of the research, however, are preliminary. Aside from the fact that the camera obscura isn’t the best way to record sunspots, Hayakawa says Kepler’s records are all it is, at least for now. “Ideally, we need more sunspot records from the early 17th century to make this conclusion stronger,” he concludes.
2024-08-20 09:00:00
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