Weightlessness is a condition in which the body does not experience support reactions. More details about what it is and where it can be felt, and will be discussed in this article.
Static
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 has flown a considerable distance from the planet. It should be understood that its weight does not completely disappear.
The fact is that gravity from massive objects such as planets and stars, although it decreases with distance, 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 gravitational field.
Dynamic
Another type of weightlessness is dynamic. It is constantly tested by astronauts and pilots. The gravitational field of a massive object can be leveled out by free fall on it. For this, it is necessary that the object pick up a certain speed and become a satellite.
Having gained the necessary speed, the satellite begins to transition into a state of constant free fall. Items inside it will be in a state of weightlessness. This speed is called the first cosmic.
For planet Earth, for example, the speed is about 8 kilometers per second. For the Sun - already 640. It all 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 velocity approaches the speed of light.
Weightlessness on Earth
It turns out that you can experience the state of weightlessness without leaving the planet. True, for a very short period. For example, a passenger traveling on a curved bridge will experience weightlessness for some time in the upper part of the convexity of the bridge.
Passengers traveling on public transport along a bumpy road constantly experience the effect of weightlessness every time a bus runs into a pit or bump. For a short period of time they are in a state of free fall.
Entertainment
Recently, special training grounds have appeared in the field of entertainment industry, where everyone can experience zero gravity.
After passing the medical board and paying a certain amount of money, you can get on board an airplane that flies along a wave-like path, and during the peak people can experience an unusual feeling of weightlessness for half a minute.
The pilot of the aircraft through the intercom selects the onset of zero gravity. This is a safety feature. The fact is that after a free fall, the aircraft is rapidly gaining altitude. At the same time, people on board experience a diametrically opposite effect - overload.
Sometimes this value reaches three times the value of the acceleration of gravity. In other words, body weight in zero gravity will be three times more than natural. If you fall from a height of several meters with such a body weight, you can very easily get injured.
For these purposes, specially trained instructors are sitting on board the aircraft in the weightless compartment. Their task is to drop on time those people who did not manage to meet the given time interval on the floor of the plane.
A series of ups and downs occurs up to twenty times in a single flight.
In Russia, for example, for those who want to feel weightlessness, there is a special centrifuge, which is located in the training center for astronauts and pilots. Again, after a medical examination and a cash contribution of about 55 thousand rubles, a person can feel the effect of weightlessness.
Effects on the human body
By definition, weightlessness is absolutely harmless to the human body. Difficulties begin when it lasts several days, weeks or months.
In most cases, this applies only to the inhabitants of space stations. The astronauts, who have been on board the spacecraft for a long time, begin to experience significant discomfort. This is primarily due to the vestibular mechanism.
On Earth, in the usual conditions, the otoliths of the vestibular apparatus press on the nerve endings, thus telling our brain where the top and bottom are, orienting the human body in space.
Weight and weightlessness
It is quite another thing when the body weighs nothing. All processes in it proceed differently. Due to the lack of otolith pressure, a spatial orientation disorder occurs. The concept of "top" and "bottom" in space completely disappears. Lack of physical activity also harms the human body. In this state, muscle tissue atrophies if no measures are taken. With its degradation, bone tissue also suffers. In the absence of load, less phosphorus enters the bones of the body.
There are difficulties with nutrition and swallowing fluids. At the same time, all liquids tend to take a spherical shape, which makes everyday things very difficult. Even a common cold in zero gravity can be a very difficult test for the body due to the fact that sputum is not excreted by gravity, but form spherical drops.
To maintain the necessary tone, the astronauts constantly train for several hours a day. When going to bed, they tie themselves with special straps so as not to get injured during sleep.
To power the astronauts developed special food in tubes and bread that does not crumble.
Before experiencing weightlessness for a long time, a person must feel its effect on the earth in order to find out how the absence of gravity will affect it in the future.