It can be assumed that some hypothetical particle is already moving faster than light but it is impossible to accelerate this particle from the usual sublight speed to the required superluminal speed. Scientists note that despite the possibility of the superluminal motion of the ship, in practice it is almost no different from the superluminal motion of any other physical body since today there are no known ways to accelerate physical objects to superluminal speeds. In addition, the authors found a way to reduce the total energy of the ship for a model with axial symmetry at a fixed speed РІР‚вЂњ for this they proposed to make the shell flatten in the direction of travel.Р”Р„ccording to calculations, a reduction in the longitudinal size of the ship will lead to a directly proportional (by the same factor) change in its total energy.Р’В This could facilitate the creation of warp drives based on matter with negative energy density РІР‚вЂњ a flattened ship would need less exotic material. However, for a shell with a mass of the order of the EarthРІР‚в„ўs mass and a radius of 10 meters, the deceleration will be only hundredths of a percent РІР‚вЂњ that is, in a year, the internal and external time will differ by only a few hours. In this case, for an observer, time inside the ship will flow more slowly than in a frame of reference that moves outside the shell at the same speed. It turned out that sublight warp drives allow not only negative but also positive energy density РІР‚вЂњ which means that, in principle, they can be made from the matter we are accustomed to. The researchers focused their attention on a subclass of warp engines, in which the shell moves at subluminal apparent speed (up to which it is in principle possible to accelerate ordinary matter) and which allows the existence of motionless physical observers (that is, material bodies, and not just formally resting points) in the inner region.Р”Р‡or spherically symmetric distortions of space-time, scientists calculated the required energy density based on the parameters of the curvature. In the extended model, the authors divided the space into three areas РІР‚вЂњ asymptotically flat outer (that is, practically undistorted at a great distance from the ship), curved РІР‚вЂњ the shell of the vehicle, and flat inner РІР‚вЂњ space for the ship itself and passengers.Р”Р„t the same time, physicists limited themselves to considering shells that are symmetric about the axis of motion of the apparatus and are stationary from the point of view of an observer in the inner region, that is, they demanded the existence of a global frame of reference for the rest of the shell. Credit: Alexey Bobrick, Gianni Martire / Classical and Quantum Gravity, 2021Р”Р„lexey Bobrick and Gianni Martire of the New York Laboratory for Applied Prospective Propulsion Physics generalized the Alcubierre warp drive idea to a wider class of space-time distortions than the scientist originally proposed. New possibilities Warp drive model: an axially symmetric shell with curved space-time surrounds the РІР‚СљflatРІР‚Сњ area in which the traveler is located.

Thus, until recently, it was believed that for this type of travel, among other things, one would first have to find a way to create a negative energy density. In general relativity, the source of space-time distortion is matter РІР‚вЂњ that is, its distribution in spaceР’В determinesР’В how exactly the geometry is curved.Р’В This connection can be used in the opposite direction РІР‚вЂњ to determine by the type of distortion of space-time, what distribution of matter causes it and what properties the source substance has.Р”Р‡or the Alcubierre warp drive, such reasoning leads to the fact that the device must necessarily contain areas with a negative energy density.

Superluminal travel nasa