Why astronauts inaccessible artificial gravity?

In space, although all masses in the Universe obey the force of gravity, as usual, there is no “top” and “bottom”, as on Earth, since the spacecraft and everything on board is accelerated by gravity with the same speed.

If you place a person in space, away from the gravitational influences experienced by him on the surface of the Earth, he will experience weightlessness. Although all the masses of the universe will continue to attract it, they will continue to attract the spacecraft, so the person will "float" inside. In TV shows and movies like Star Trek, Star Wars, Battle Battle Cruiser Galaxy and many others, we are always shown how the crew stand on the floor of the ship, regardless of other conditions. This would require the possibility of creating artificial gravity - but given the laws of physics in the form in which we know them today, this is too difficult a task.


Captain Gabriel Lorca on the Discovery Bridge during a simulation of a battle with the Klingons. The whole team is attracted by "down" artificial gravity - today technology from the field of science fiction

An important lesson of the equivalence principle is associated with gravity: a uniformly accelerated frame of reference is indistinguishable from a gravitational field. If you are in a rocket and cannot look out, you will not have a way to understand what is happening: is the force of gravity pressing you down or does the rocket accelerate uniformly in one direction? This idea led to the formulation of the general theory of relativity, and, after more than a hundred years, this is the most correct description of gravity and acceleration known to us.


The identical behavior of a ball falling on the floor, in an accelerating rocket and on Earth demonstrates the Einstein principle of equivalence

There is one more trick we could use: make the ship spin. Instead of linear acceleration (acceleration of the rocket), you can get a centrifugal, in which a person on board will feel how the ship hull attracts him. This is the famous film „2001: a space odyssey“, and this power, if the ship is large enough, would be indistinguishable from gravity.

But that's all. Three types of acceleration - gravitational, linear and rotational - are the only forces at our disposal that exert a gravitational effect. And for those on board the spacecraft, this is a big, big problem.


The concept of the 1969 space station, which was supposed to be assembled in orbit from the Apollo program stages used. The station had to rotate around the central axis and generate artificial gravity.

Why? Because in order to travel to a different star system, you will have to speed up the ship on the way there, and on arrival you will have to slow it down. If you can not defend yourself from these accelerations, a fiasco awaits you. For example, to accelerate to the “impulse speed” of the “Star Trek”, up to several percent of the speed of light, one would have to withstand an acceleration of 4000 g for an hour. This is 100 times more acceleration, which will prevent blood flow in your body - a very unpleasant situation, no matter how cool.


The launch of the shuttle Columbia in 1992 shows that the acceleration of the rocket does not occur instantaneously, but lasts quite a long time, many minutes. The spacecraft acceleration should have been much larger than the human body can withstand.

Moreover, if you do not want to be weightless during a long journey, and undergo terrible biological effects like loss of bone mass and cosmic blindness, it is necessary that a constant force act on your body. For forces other than gravity, this would not be a problem. For example, for electromagnetic exposure one could place a command in a conductive envelope and this would eliminate all external electromagnetic fields. And then inside it would be possible to arrange two parallel plates and to organize a constant electric field, which would force the charges to move in a certain direction.

Eh, if gravity worked the same way.


A schematic diagram of a capacitor, two parallel conductive plates of which have the same in magnitude and different in sign charges, which creates an electric field between them

No "gravitational conductors" exist, and it is impossible to protect oneself from gravity. It is impossible to create a uniform gravitational field between any plates in a certain part of space. The reason is that, in contrast to electricity generated by positive and negative charges, the gravitational “charge” is of the same type, mass-energy. The force of gravity always attracts, and nothing can be done about it. We'll have to do everything possible with the three available types of acceleration - gravitational, linear and rotational.


The vast majority of quarks and leptons of the Universe consist of matter, but for each of them there are also antimatter particles, the gravitational masses of which are not determined

The only way to create artificial gravity that can protect you from the effects of a ship’s acceleration and give you a constant pull “down” without acceleration would be to open a new type of negative gravitational mass. All particles and antiparticles discovered by us have a positive mass, but these are inertial masses, that is, masses related to the acceleration or creation of particles (that is, m is from the equations F = ma and E = mc ² ). We have shown that the inertial and gravitational masses for all known particles are the same, but have not yet performed sufficiently thorough tests for antimatter and antiparticles.


The ALPHA collaboration, closer to other experiments, approached the measurement of the behavior of neutral antimatter in a gravitational field.

And in this area, experiments are going on right now! In the ALPHA experiment at CERN, antihydrogen was obtained - a stable form of neutral antimatter - and now they are working to isolate it from all other particles at low speeds. If it is sensitive enough, we can measure in which direction the antimatter will move in the gravitational field. If it falls down, as usual, then its gravitational mass is greater than zero, and it cannot be used to create a gravitational conductor. But if it falls up, it will change everything. A single experimental result will suddenly make artificial gravity physically possible.


The ability to get artificial gravity is tempting, but it requires the existence of a negative gravitational mass. Antimatter may be such a mass, but this is still unknown.

If antimatter has a negative gravitational mass, then by making the ceiling of the room antimatter, and the floor is made of matter, we can create an artificial gravitational field that constantly pulls you down. Having built the shell of the ship from the gravitational conductor, we will protect everyone inside it from the forces of super-high acceleration, which otherwise would be fatal. And, best of all, people in space will no longer suffer from negative physiological effects, from a violation of the vestibular apparatus to atrophy of the heart muscle, which plagues modern cosmonauts. But until we open a particle (or a set of particles) with a negative gravitational mass, artificial gravity can only be obtained through acceleration.