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BIG ENCYCLOPEDIA FOR CHILDREN AND ADULTS
What are sunspots? Detailed answer
Directory / Big encyclopedia. Questions for quiz and self-education Did you know? What are sunspots? Sunspots are dark formations on the solar disk. A well-developed spot has a dark shadow (core) surrounded by a lighter penumbra, in which radially arranged light veins are visible. The shadow seems very dark only in contrast with the dazzlingly bright visible surface (photosphere) of the Sun, however, the spots themselves shine very brightly, since their temperature is quite high (4300-4700 degrees Kelvin, that is, 1000-1500 degrees lower than the temperature of the photosphere) . Once a spot was observed that had a temperature of "only" 3680 kelvins. The shade temperature is about 5500 kelvins. Sunspots are hotter than molten steel and brighter than electric arcs. The smallest sunspots - the so-called pores - have diameters of several hundred kilometers, the diameter of large spots reaches 100 thousand kilometers. Occasionally, giant spots appear. So, for example, from March 8 to March 17, 1947, a complex-shaped spot 214 kilometers long was observed. The larger the area of the stain, the more durable it is. Sunspots have a strong magnetic field. The passage of large sunspots or groups of sunspots through the central meridian of the Sun is often accompanied by magnetic storms on Earth. The spots move from the eastern edge of the Sun to the western, thereby demonstrating the rotation of the Sun around its axis; At the same time, they themselves move somewhat along the solar surface. The proportion of the visible surface of the Sun covered by sunspots is a characteristic of solar activity. It is very interesting that observations of sunspots became one of the reasons for the collapse of the Aristotelian-Ptolemaic model of the Universe, according to which stars are ideal indivisible spheres. Author: Kondrashov A.P.
Who is Achilles? Surely you have heard the phrase "Achilles' heel", meaning the weak spot of someone or something. Who is this Achilles, or, as he is also called, Achilles? He was one of the heroes of Ancient Greece. When he was born, his mother, the sea goddess Thetis, bathed her son in the underground river Styx to make the child invulnerable to weapons. As a result, Achilles' whole body became stronger than armor, with the exception of the heel, for which his mother held him, dipping the input! Later, this fatal circumstance determined his fate. He grew into a handsome youth, the strongest and swiftest in movement among mortals, who delighted the eyes of all who met him. In the end, he became the most famous among the Greek soldiers during the war with Troy. Achilles was the hope of the entire Greek army. However, after the leader of the Greeks Agamemnon took away from him a girl named Chryseis, captured by Achilles, he became furious and refused to fight further. The Greeks, left without their hero, could not withstand the sudden attack of the Trojans. Then Achilles allowed his close friend Patroclus to take part in the battle in his armor. However, Patroclus died at the hands of the Trojan hero Hector, who captured the armor of Achilles. Upon learning of what had happened, Achilles subdued his anger and decided to avenge his friend. Having reconciled with Agamemnon, he received new armor and a shield from the hands of the god Hephaestus and, having entered the battle, defeated Hector. To quench his thirst for revenge, he dragged the corpse of Hector around the tomb of Patroclus. Later, in another battle, Hector's brother Paris, shooting a poisoned arrow at Achilles, hit him in the heel, the only vulnerable spot on the hero's body, and he died from his wound.
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