Why is it difficult for sharks to sleep? Detailed answer

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Why is it difficult for sharks to sleep? Detailed answer

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Why is it difficult for sharks to sleep?

At one time, ichthyologists believed that sharks never sleep. The fact is that they do not have gill covers, with which ordinary bony fish pump water through the gills. In order to breathe, a shark must constantly swim.

However, a few years ago, an underwater cave was found in the Red Sea, where sharks still manage to sleep: the canal system creates a constant "draught" in the cave. Sharks sleep in rows in a channel with their heads against the current, and their gills are washed by the current.

Author: Kondrashov A.P.

Random interesting fact from the Great Encyclopedia:

How was the light year discovered?

Although we cannot fully explain what light is, we can measure it quite accurately. We have a pretty good idea of how fast light travels. Since a light year is simply the distance a ray of light travels in a year, the true discovery was related to the speed of light. This was done by a Danish astronomer named Ole Römer in 1676. He noticed that the eclipses of one of the satellites of Jupiter come later and later as the Earth moves in its orbit to the far side of the Sun, opposite to that where Jupiter is located.

Then, when the Earth returned to its previous position, the eclipses again began to occur according to the previous schedule. The time difference was about 17 minutes. This could only mean that this time is required for the light to travel a distance equal to the diameter of the earth's orbit. This distance is known to be approximately 186 miles. Since it took light about 000 seconds (about 000 minutes) to travel this distance, this meant that the speed of light was about 1000 miles per second.

Already in modern times, Professor Albert Michelson has spent years trying to accurately determine the speed of light. Using a different method, he got a result of 186 miles per second, and this is now considered a completely accurate figure. If we multiply this speed by the number of seconds in a year, then it turns out that in a year light travels 284 miles - this distance is called a light year.

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