Warp drive is a hypothetical faster-than-light (FTL) propulsion system that has been featured in many works of science fiction, most notably Star Trek. A spacecraft equipped with a warp drive may travel at apparent speeds greater than that of light by many orders of magnitude1. The idea is to create a bubble of warped space-time around the spacecraft, so that the space ahead of it contracts and the space behind it expands, allowing the spacecraft to move faster than light without violating the laws of physics.
However, most of the existing theoretical models for warp drives require exotic forms of matter or energy that are either unphysical or beyond our current technological capabilities. For example, the Alcubierre warp drive, proposed by Mexican physicist Miguel Alcubierre in 1994, would need a negative energy density to create the warp bubble23. Negative energy is a hypothetical concept that violates some of the basic assumptions of classical physics, such as the conservation of energy and the second law of thermodynamics. It is not clear whether negative energy exists in nature or can be artificially generated.
But now, a recent paper by US-based physicists Alexey Bobrick and Gianni Martire has resolved many of the issues with the Alcubierre warp drive and proposed a new theoretical design that could allow FTL travel based on conventional physics4. Their paper, published in the journal Classical and Quantum Gravity, introduces a new framework for warp drives that does not rely on negative energy or exotic matter, but rather on the manipulation of the curvature of space-time using positive energy sources.
The key idea of their framework is to use a solenoidal field, which is a type of magnetic field that has no divergence, to create the warp bubble. A solenoidal field can be generated by a coil of wire or a torus-shaped magnet, and it has the property of being invariant under Lorentz transformations, which are the mathematical rules that describe how physical quantities change under different frames of reference. This means that a solenoidal field can maintain its shape and strength regardless of the motion of the observer or the source.
By applying the solenoidal field to a region of space-time, Bobrick and Martire show that it is possible to create a warp bubble that can travel faster than light without violating any physical laws or causality. The warp bubble would have a flat region in the center, where the spacecraft and its passengers would reside, and a curved region around it, where the space-time would be distorted. The curvature of the space-time would depend on the strength and shape of the solenoidal field, and it could be controlled by changing the parameters of the field generator.
The authors also show that their framework can accommodate various types of warp drives, such as the Alcubierre warp drive, the Krasnikov tube, and the Natario warp drive, as special cases. They also propose some novel warp drive solutions, such as a warp drive that can travel in a circular orbit, a warp drive that can travel in a helical path, and a warp drive that can travel in a zigzag pattern. They also discuss some of the potential applications and limitations of their warp drive technology, such as the possibility of time travel, the effects of gravity, and the stability of the warp bubble.
The paper by Bobrick and Martire is a significant contribution to the field of warp drive research, as it opens up new possibilities for FTL travel using conventional physics and technology. However, the authors also acknowledge that their framework is still theoretical and that there are many challenges and uncertainties that need to be addressed before warp drives can become a reality. For example, they estimate that the energy required to create a warp bubble that can travel at 10 times the speed of light would be equivalent to the mass-energy of Jupiter, which is far beyond our current capabilities. They also point out that the effects of quantum mechanics and quantum gravity, which are not accounted for in their classical framework, may have important implications for the feasibility and safety of warp drives.
Nevertheless, the paper by Bobrick and Martire is a fascinating and inspiring piece of work that shows that warp drives are not just a science fiction fantasy, but a scientific possibility that deserves further exploration and investigation. Warp drives could revolutionize the fields of space exploration, astronomy, and cosmology, as they could allow us to travel to distant stars and galaxies, observe the early universe, and test the fundamental laws of physics. Warp drives could also have profound implications for our understanding of the nature of reality, the origin of the universe, and the meaning of life.