Science has answered many fundamental questions, but some areas of the surrounding reality still remain "blank spots" even for scientists themselves. Why is gravity acting on us? How can domestic fish predict earthquakes? Why do people yawn? Here is a selection of interesting questions to which modern scientific knowledge does not yet provide answers.
1. Why do we yawn?
On this score, there are many theories, including the most ridiculous. Two of the most likely deserve attention.
The first says that yawning helps relieve stress from the brain and improve brain function. That is why, according to psychologists from the University of Albany in New York, we usually yawn before bed - by that time, brain performance decreases, the same is observed with lack of sleep.
But if yawning only helps to "spur" our brain, why is it so contagious? The adherents of the theory answer that this came from our distant ancestors: when the leader of the flock yawns, thereby showing that he is not in the best shape at the moment, the whole flock begins to do the same in order, so to speak, to increase collective vigilance earlier. identify potential threats.
The second theory is that yawning unites and, as it were, makes people sympathize with each other - the one who yawns after someone as if subconsciously wants to say: "Yes, buddy, as I understand you."
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2. Why do people sometimes spontaneously ignite?
All that science knows for sure about this is that people sometimes really flare up like matches.
One of the first officially recorded victims of spontaneous combustion was an Italian knight of the mid-17th century: this seigneur was engulfed in fire after excessive consumption of wine. Over the centuries, about 120 known cases have occurred, but many, scientists are sure, cannot be attributed to spontaneous combustion. There were many smokers among the victims, and one curious theory is that smoking can burn the deep layers of the skin and cause the layer of subcutaneous fat to ignite - all together this is similar to the principle of a candle and a wick.
An alternative theory says that the cause of the eerie outbreaks is methane accumulating in the intestines, and the "spark" is given by a certain interaction of enzymes.
These two explanations have one problem - scientists cannot verify them, so there is still no answer to the question of why this is happening.
3. How does the placebo effect work?
When a new drug goes through clinical trials, there is always a so-called control group among the volunteers, whose indicators serve as a starting point for scientists. Its participants are told that they are given the test drug, however, in reality they receive only slightly tinted "dummies" - placebo (Latin placebo - "I will like it").
Some of the volunteers "feel" the effect of the drug, which they are supposedly given, moreover, there are objectively recorded effects of the placebo, corresponding to the action of the present drug. Many people believe that sometimes people claim to feel better, but this is just trying to convince themselves.
Conflicting evidence gives rise to numerous theories: Pavlov's followers, for example, say that the patient at the physiological level creates conditions for recovery, because the treatment should help. Some talk about the therapeutic effect of communicating with the doctor, others about the unconscious unwillingness to spoil the statistics of the experiment.
Be that as it may, pharmaceutical giants dream of uncovering the mystery of the placebo effect in order to deprive the scammers who sell dummies of the opportunity to profit, because the development of real drugs is expensive and takes a long time, but because of the autosuggestion of people, they sometimes cannot compete with "tricks"
4. Who was the last common ancestor?
A whale and a bacterium, an octopus and an orchid - it would seem that they have nothing in common, but if you dig deeper, it turns out that there are still similarities.
Almost all living things contain proteins and nucleic acids: all living organisms contain a genetic code, and the sequence of the human genome resembles a family tree - this suggests that all the diversity of life can be reduced to one universal ancestor.
In theory, calculating a common ancestor will help you look deeper into the origins of life. Scientists claim that the last universal common ancestor (LUCA) about 2.9 billion years ago gave two branches of development - bacteria and eukaryotes (the latter later developed into plants, animals, and beyond). Unfortunately, the genetic material of that era is rather scarce, since it was repeatedly reshuffled and changed in the process of evolution.
But some of the preserved genetic properties of proteins and nucleic acids suggest who LUCA looked like: - the cell that all living organisms are made of.
5. How does memory work?
For a long time, scientists have assumed that memory mechanisms are contained in the hippocampus, the cerebral cortex, or scattered in an undefined group of neurons.
Scientists at the Massachusetts Institute of Technology have for the first time managed to manipulate the memory of mice by influencing some neural connections. This is, of course, a step forward, but how does the brain determine which ligament to use?
This "trick" has not yet been fully understood: studies show that when a memory occurs, the same brain cells are activated that are involved directly in the experience, in other words, memory does not just accumulate impressions, and then "takes them out" - it is more like construction of the “same” situation.
6. Is it true that animals predict earthquakes?
This idea is good, but scientists need proof.
Cases of strange behavior of pets before any cataclysm have been known since ancient Greece, but all these stories are in the nature of an anecdote, and in general, what behavior of an animal can be considered strange enough to talk about "prediction"? In addition, they usually talk about it after what happened.
It is undeniable that animals are sensitive to changes in natural conditions - from seismic waves to disturbances in the electromagnetic field, but it is unclear whether such changes precede earthquakes. And if we ourselves cannot predict an earthquake, then when should we start recording the "strange" behavior of pets?
It is even more difficult to set up an experiment, because for this it is necessary to arrange a cataclysm. Several "happy" coincidences occurred in Neftegorsk, when the earthquake began during experiments on animals, but the data obtained in this case are rather contradictory.
7. How do body parts “know” that they need to stop growing?
Each animal, consisting of trillions of cells, at the beginning of the developmental path was only one single cell: the growth process, as a rule, is tightly controlled, but sometimes failures occur, and it turns out, for example, that a person has one leg slightly shorter than the other. What influences this?
Here are the main four proteins of what will become the Salvadoran warty hippopotamus, sending a signal through special "communication channels" that it's time to stop organ development. The signal stops the production of protein, which serves as a building material, and this is where the specific ideas of scientists end.
What generates a signal? What growth mechanisms other than protein production does it affect? Scientists also continue to study these "communication channels", suggesting that they can "turn off" the mechanism of division of cancer cells.
8. Are there human pheromones?
Do you smell someone else's fear? Can you, for example, feel a rat in the distance? Animals have long and successfully communicated at the level of chemical signals, but is man capable of this?
Some talk about an undoubted change in behavior and the reaction of human physiology itself to chemosignals, but it is still impossible to say for sure what is the initiator of these changes. Let the inscriptions on perfumes and shower gels say that it is this “pheromone” agent that will make you irresistible, scientists do not yet know any pheromones that can affect humans.
Even if some "chemical signals" exist in a person, it is not entirely clear how the receiving side "decodes" this signal. In mammals and reptiles, this purpose is served by the vomeronasal organ, which is also present with us, but has olfactory functions, and its sensory cells are not connected with the central nervous system.
9. How does gravity work?
There are four main forces that keep the Universe from falling apart: electromagnetism, strong and weak nuclear interactions, and gravity. Gravity of these four is the least noticeable, which is why its properties are not easy to study when using small objects, in laboratory conditions, but, for example, a strong nuclear interaction is 1026 times larger than a weak one. Despite all the efforts of physicists to explain the phenomenon of attraction of objects to each other using the principles of quantum mechanics, or General Theory of Relativity, the essence of this interaction will not be clear until the development of the Unified Theory of Everything.
It is also unclear what the gravitational interaction between objects is connected with: only the construction of many super-colliders to detect a hypothetical graviton - an elementary massless particle-carrier of gravitational interaction - can help. Some of the scientists seek to find evidence of its existence, while others are confident that this will only confuse everything.
10. How many species are there on Earth?
For about 200 years, scientists have been compiling a general classification and description of various animal species known to science, and this grandiose work will probably not be completed soon.
In the last decade alone, more than 16 thousand new species of animals have been announced, and at the moment about 1.2 million have been classified. How many unknown living organisms still exist?
Based on this, it can be calculated that about 300 thousand people must devote their lives to cataloging all living things - this is an extremely long and laborious process, because many habitats of many unexplored species are located in developing countries, where research is quite problematic, and 80% of living beings and does live in the ocean depths.
With this in mind, several groups of scientists give differing estimates of the number of species yet to be discovered - the numbers range from 19,264 to about 15 million.