What is weightlessness from the point of view of a physicist and an astronaut?

What is weightlessness? Soaring cups, the ability to fly and walk on the ceiling, easily move even the most massive objects - such is the romantic idea of this physical concept. If you ask the astronaut what is weightlessness, he will tell you how difficult it is in the first week on board the station and how long after the return has to be restored, getting used to the conditions of gravity. The physicist, most likely, omits such nuances and with mathematical precision will open the concept with the help of formulas and figures.

Definition

Let us begin our acquaintance with the phenomenon from the discovery of the scientific essence of the matter. The weightlessness of a physicist determines how a state of a body is when its motion or external forces acting on it do not lead to a mutual pressure of the particles on each other. The latter always arises on our planet, when an object moves or rests: gravity and the oppositely directed reaction of the surface on which the object is located presses on it.

The exception to this rule is the cases of free fall, that is, falling with the speed that the body gives gravity. In such a process there is no pressure of the particles on each other, there is zero gravity. Physics says that the same principle is based on the state that arises in spacecraft and sometimes in airplanes. Weightlessness appears in these vehicles when they move at a constant speed in any direction and are in a state of free fall. An artificial satellite or spacecraft is delivered to orbit using a carrier rocket. It gives them a certain speed, which is maintained after the machine turns off its own engines. The ship starts to move only under the influence of gravity and there is a weightlessness.

Disadvantages

At the beginning of the space age , the question arose about the reaction of the body to the absence of attraction. Weightlessness in space was a phenomenon not fully understood, albeit predictable. Today, its impact on the human body as a whole has been studied.

A finely tuned body mechanism undergoes tremendous stress in the absence of gravity. Cosmic weightlessness leads to a disruption of the hydrostatic pressure of the fluid in the body (primarily of the blood), to the disappearance of the habitual load on the locomotor apparatus. Some time after arriving at the ship or station astronauts are subjected to the so-called syndrome of adaptation to outer space.

Influence on the body

What is weightlessness for a beginner? This is dizziness, loss of orientation. There may be various illusory feelings. The body begins to adapt to the new conditions, but time is needed for perestroika. As a rule, the body's work is adjusted within ten days.

Then, however, the changes continue to occur. Because of the lack of gravity, the overall load on the body decreases. As a result, astronauts lose weight in weightlessness, their efficiency decreases and, on the contrary, fatigue increases. The ratio of chemical elements in tissues also changes: bones lose some of the minerals they need. Often, after returning to Earth after a long stay at the station, the astronaut becomes higher by a few centimeters. The reason lies in the same weightlessness. The results of such a jump in growth are not the most pleasant: pain can occur, nerve infringement.

At home

The consequences of flights for astronauts are not limited to this. After returning to Earth, they have to adapt for some time back to the force of gravity. What is weightlessness for an astronaut who completed the flight? First of all, it's a habit. Consciousness for some time refuses to accept the fact of gravity. As a result, it is not uncommon for an astronaut, instead of putting a cup on a table, simply letting go of it and realizing the error, only when he heard the sound of the broken glass on the floor.

Food

One of the most difficult and at the same time interesting tasks for the organizers of manned flights is to provide astronauts with easy digestible food under the influence of weightlessness in a convenient form. The first experiments did not cause much enthusiasm among the crew members. Indicative in this respect is the case when the American astronaut John Young, contrary to strict prohibitions, carried a sandwich on board, which, however, did not become so as not to violate the charter even more.

For today with a variety on orbital stations there are no problems. The list of dishes available for Russian cosmonauts is 250 points. Sometimes a cargo ship, starting to a station, delivers a fresh dish ordered by someone from the team.

The basis of the diet is sublimated products. All liquid dishes, drinks, and also mashed potatoes are packed in aluminum tubes. Tare and shell products are thought out in such a way as to avoid the appearance of crumbs floating in weightlessness and able to get into someone's eye. For example, a cookie is made small enough and covered with a shell, melting in the mouth.

Familiar setting

At stations like the ISS, all conditions are trying to bring to the familiar terrestrial. This is the national dishes in the menu, and the movement of air, and even the designation of the floor and ceiling, is necessary both for the functioning of the organism and for the normal operation of the equipment. The latter has, rather, psychological significance. The cosmonaut in zero gravity does not care what position to work in, however, the allocation of the conditional floor and ceiling reduces the risk of losing orientation and contributes to faster adaptation.

Weightlessness is one of the reasons why not everyone takes cosmonauts. Adaptation on arrival at the station and after returning to Earth is comparable with acclimatization, amplified several times. A person with poor health of such a load may not survive.