Why does the eye of Medusa, held by the starry Perseus, wink? Detailed answer

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Why does the eye of Medusa, held by the starry Perseus, wink? Detailed answer

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Why does the eye of Medusa, held by the starry Perseus, wink?

On ancient star maps, Perseus holds a high-lifted sword in his right hand, and the terrible head of the Gorgon Medusa in his left.

Observing the sky, the Arabs in the Middle Ages noticed that one eye of the gorgon shines evenly, and the second winks from time to time. Therefore, they called the blinking eye of Medusa (the star of Beta Perseus) the devil (in Arabic - Algol). In 1782-1783, the English astronomer John Goodryke closely observed the strange behavior of Algol. He managed to establish a strict periodicity in the "wink" of the Gorgon's eye.

For 60 hours, Algol retains its brilliance of a star of 2,2 magnitude, and then, for almost 9 hours, the brightness decreases to 3,5 magnitude and again increases to its previous value. The total period of change in visual magnitude is 2,867 days. Goodryk proposed a brilliant hypothesis to explain Algol's variability: "If it were not too early to express considerations about the causes of variability, I could assume the existence of a large body orbiting Algol."

It was possible to confirm the correctness of this hypothesis only a century later, when periodic shifts of spectral lines were noticed in the Algol spectrum, and the period of these shifts exactly corresponded to the period of brightness change.

Thus, it was proved that Algol is a spectroscopic binary star, and brightness fluctuations are caused by a periodic eclipse of the main star by its companion. So the winking eye of the celestial Medusa turned out to be the first eclipsing variable star discovered by man.

Author: Kondrashov A.P.

Random interesting fact from the Great Encyclopedia:

How do owls hunt?

Owls are birds of prey. They are the best hunters of all predators. In an owl, everything seems to be created specifically for hunting. The owl has powerful, needle-sharp claws that pierce the victim like the teeth of a trap. The claws are connected into one paw, which the owl can turn in any direction. In most species of owls, large eyes see better in the evening or at night in the moonlight than in the daytime. Owls have more sensitive ears than other birds. Their ears can be of various shapes, they are hidden on the head under feathers.

The owl has soft, down-lined wing feathers. This allows you to make the flight of an owl almost silent, which is very helpful when hunting. Owls usually hunt at sunset, at dusk or in moonlight. They hear mouse rustling for many meters. When an owl listens from its hunting perch, it pushes back the feathers and skin covering its ears. In this case, an auricle is formed, which perceives the slightest sound.

When the owl locates the prey by hearing, it suddenly and accurately attacks and sticks sharp claws. Owls feed on mammals such as mice, squirrels, and rabbits. They also eat lizards, frogs, birds and even fish. Owls catch mice better than any human-made mousetrap.

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Lie detector for eggs 11.06.2005

British and Australian scientists have figured out how to distinguish between eggs laid in a poultry farm and in a village barn.

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Scientists have done a lot of work: they studied more than eleven thousand eggs that laying hens laid in three different places - in cages, in village barns and right in the field. As it turned out, the cell leaves very clear marks on the eggshell - two white lines at a distance of 2-2,5 cm.

The calculation shows: if in a batch of 90 eggs there are at least five pieces with such white stripes, then with a probability of 0,999 regrading takes place. Perhaps the supplier is trying to slip dietary eggs from the poultry farm instead of peasant or farm eggs. Dust marks naturally disappear when washed, so such control should be carried out on unwashed eggs.

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