Anna Dalton

“A planet is…” Scientists have proposed to change the definition of a planet, because the old one is outdated

Planetary scientists from the University of California at Los Angeles and colleagues have proposed a new definition of a planet for the International Astronomical Union (IAU). This organization officially names all space objects and in 2006 adopted the current definition, in which one of the criteria is the rotation of a celestial body around the Sun. And this immediately weeds out all the celestial bodies around other stars outside our Solar System.

Other criteria in the definition of MAC, on the contrary, lack specificity, scientists believe. An article with their new definition and detailed arguments has been published on the arXiv preprint server.

At the moment, according to the IAU classification, a planet is considered to be a celestial body orbiting the Sun, massive enough to take a spherical shape under the influence of its gravity and remove other objects near its orbit.

“Now we know about the existence of thousands of planets, but the definition of the IAU does not apply to them. We propose a new definition that can be applied to celestial bodies orbiting any star, stellar remnant or brown dwarf,” planetary scientist and astrophysicist Jean-Luc Margot, professor at the University of California at Los Angeles.

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Football in its modern form appeared in England in the XIII century, and already at the beginning of the XIV the Lord Mayor of London forbade chasing the ball in the city, as he believed that riots that regularly occur after games could be dangerous. Sociologists of the 20th century believed that football hooligans are exclusively people from disadvantaged families, representatives of the social grassroots and other marginals. However, more thorough research has shown that this is not the case.

In one gate: how and why respectable football fans become hooligans

The herd instinct
According to a 2006 VTsIOM survey, matches in Russia are attended mainly by people with above-average incomes. And a study conducted in 2011 by specialists from St. Petersburg State University did not reveal a significant difference in the level of aggression between those who are not interested in football at all and “ordinary” fans (this indicator is still higher for fans). However, even the calmest spectators of football matches are capable of yelling offensive chants for hours, and sometimes threatening to kill fans of the “enemy” team.

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Domestic cats will do almost anything to avoid contact with water. But the fear of water is not at all peculiar to their wild cousins. Lions, tigers and jaguars had to adapt to the water in order to survive, scientists who observed the lions came to this conclusion.

A research team in Uganda filmed two male lions swimming in a pond in Queen Elizabeth National Park. But what was unusual was the distance they traveled and the danger lurking on the way: the lions swam about 1.5 km through the Kazinga Canal, which connects two lakes in the park. The channel is home to a large number of hippos and Nile crocodiles, which are known to attack lions. In the footage, captured on a high-resolution thermal imaging camera, the lions make three attempts to cross the 6-meter-deep channel (and return to shore) before starting to swim south of the park.

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Archaeologists have discovered one of the earliest Christian buildings in the Persian Gulf — the first physical evidence of a long-lost community. Radiocarbon dating indicates that the building in Samahij, Bahrain, was founded between the 4th and 8th centuries, and subsequently abandoned after the population converted to Islam.

Excavations carried out by British and Bahraini archaeologists under a mound in the village cemetery helped to discover a large building with eight preserved rooms — a kitchen, a dining room, a work room and three living rooms. The building has been preserved because a mosque was built on it.

It is possible that the building was the palace of the bishop of the diocese, which is listed in historical sources as Masmahig. Records show that relations between Meshmahig and the central church authorities were not always smooth, especially after the bishop was excommunicated in 410.

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We perceive the world in different ways

Human vision is difficult to call perfect in terms of acuity, visible color spectrum or viewing angle, but people see well against the background of most animals. “Around the World” “looked” at the same image through the eyes of a man, a dog, a fish, a turtle, a fly, a mouse and a parrot.

Dog

He has vision that is insensitive to red and orange colors, but he distinguishes shades of gray much better than a person. He sees well at night. It has weak farsightedness (up to + 0.5 diopters), perfectly recognizes moving objects from a distance of 700-900 meters. But it does not distinguish well anything closer than 35-50 centimeters.

Parrot

It is capable of perceiving the entire color spectrum and ultraviolet visible to humans. Tetrachromatic: the main colors are red, green, blue, ultraviolet, and the last one is the most important of them. Visual acuity is several times higher than that of a human. Clearly sees over long distances, has the ability to adjust vision depending on the distance to objects.

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