What is it - weightlessness?
Weightlessness is a condition in which the body does not experience a support reaction. More details about what it is and where it can be felt, and will be discussed in this article.
There are two types of weightlessness. This is static - observed when moving away from an object with a large mass. For example, a body that flew a considerable distance from the planet. It should be understood that his weight does not completely disappear.
The fact is that gravity from massive objects,such as planets and stars, although it decreases with distance, but does not completely disappear. Its action extends infinitely far to all corners of the universe, inversely proportional to the square of the distance. This follows from the definition of weightlessness.
Thus, it is impossible to leave the zone of action of the gravitational field.
Another type of weightlessness is dynamic. It is constantly tested by cosmonauts and pilots. To level out the action of the gravitational field of a massive object can be by free fall on it. To do this, it is necessary for the object to gain a certain speed and become a companion.
Having gained the necessary speed, the satellite startsgo into a state of constant free fall. The objects inside it will be in a state of weightlessness. This speed is called the first cosmic speed.
For the planet Earth, for example, the speed isabout 8 kilometers per second. For the sun - already 640. Everything depends on the mass of the object and its density. In such space objects, where the density reaches hundreds of millions of tons per cubic centimeter - the cosmic speed is approaching the speed of light.
Weightlessness on Earth
It turns out, to experience a state of weightlessnessyou can, without leaving the planet. True, for a very short period. For example, a passenger car driving along a curved bridge will experience weightlessness for some time at the top of the bridge bulge.
Passengers traveling in public transport bybumpy road, constantly experience the action of weightlessness every time a bus runs into a pit or a hummock. For a short period of time they are in a state of free fall.
Recently, in the entertainment industry, special polygons have appeared, where everyone can experience weightlessness.
After going through a medical commission and payinga certain amount of money, you can get on board an airplane that flies along a wavy trajectory, and during a peak, people can experience an unusual feeling of weightlessness for half a minute.
The pilot of the aircraft through the intercom callsthe beginning of the action of weightlessness. This is necessary for security reasons. The fact is that after a free fall the plane is rapidly gaining ground. At the same time, people on board experience a diametrically opposite effect - overload.
Sometimes this value reaches threefoldvalues of acceleration of gravity. In other words, the weight of the body in weightlessness will be three times more than the natural weight. When falling from a height of several meters with such a body weight, it is very easy to get injured.
For these purposes, on board the aircraft in theweightlessness sit specially trained instructors. Their task is to drop in time on the floor of the plane those people who did not have time to meet this time interval.
A series of ups and downs occurs with a frequency of up to twenty times per flight of an airplane.
In Russia, for example, for those who want to feelweightlessness is a special centrifuge, which is located in the training center for astronauts and pilots. Again, after a medical commission and a cash contribution of about 55 thousand rubles a person can feel the effect of weightlessness.
Influence on the human body
By definition, weightlessness is absolutely harmless to the human body. Difficulties begin when it lasts for several days, weeks or months.
In most cases, this only applies toinhabitants of space stations. Astronauts, long time on board apparatus, begin to experience significant discomfort. First of all it is connected with the vestibular mechanism.
On Earth, in the usual conditions, the otoliths of the vestibular apparatus are pressed against the nerve endings, thus prompting our brain where the top and bottom are, orienting the human body in space.
Weight and weightlessness
It's quite another thing when the body does not weigh anything. All the processes in it proceed differently. Due to the lack of pressure of the otoliths, a disruption of orientation in space occurs. The concept of "top" and "bottom" in space completely disappears. Harm to the human body is also the lack of physical activity. In this condition, muscle tissue atrophies, if no action is taken. With its degradation, bone tissue also suffers. In the absence of a load, less phosphorus enters the bone of the body.
There are difficulties with nutrition and swallowingliquids. All liquids tend to assume a spherical shape, which makes everyday things very difficult. Even a common runny nose in conditions of weightlessness can be a very difficult test for the body due to the fact that sputum is not excreted by gravity, but forms spherical drops.
To maintain the necessary tone, cosmonauts constantly train for several hours a day. When going to sleep, they attach themselves with special straps to avoid injury during sleep.
To feed the astronauts a special food in tubes and bread, which does not crumble, is developed.
Before long time to experience weightlessness, a person must feel its effect on the earth in order to find out how in the future will be affected by the absence of gravity.