Humans have been interested in the cosmos for centuries. As early as 32,000 B.C., humans were using the night sky as an astronomical timepiece and had formed entire religions around these ‘heavenly bodies’ 34,000 years later, humans have been to the moon and back, and are currently planning on a manned mission to Mars. Such a feat would undoubtedly direct human imagination towards the possibility of traveling beyond Earth’s solar system. Though the sheer distances involved make this an incredible challenge. issue, sci-fi fans point to the ‘warp drive,’ popularized by “Star Trek” as a source of inspiration. One such fan and theoretical physicist Miguel Alcubierre did just that in his paper, “The Warp Drive: Hyper-fast Travel within General Relativity.”

In his paper, Alcubierre demonstrates a way to travel at superluminal velocities without violating one of the central tenets of modern physics: Nothing can move through space faster than the speed of light. This may sound like an impossible challenge, but as Alcubierre shows, a small change in approach can drastically alter the conclusions one can draw. The key is to realize nothing can move through space faster than light-speed, there is nothing preventing space itself from doing just that—in fact, astronomers have already established that some galaxies are moving away from Earth at faster than the speed of light. Alcubierre’s ‘warp drive’ works by warping spacetime in such a way that a traveler could be pushed by the fabric of the cosmos itself.

Unfortunately, warping spacetime in this way poses multiple issues.

First, such a contraption would require an insanely large quantity of negative energy—something that has only been observed on quantum-mechanical scales and may not even be possible to produce on macroscopic scales (Google the “Casimir effect” for more information).

Additionally, because the Alcubierre drive permits the transfer of matter, energy and information to be faster than the speed of light, in principle, this could be used to build a time machine, which poses multiple problems in itself. All these issues have most physicists believe the Alcubierre drive is unfeasible, but without confirmation that it is unequivocally impossible to produce a fuel source with a negative energy density on the scale required nothing can be ruled out just yet.

In short, don’t get your hopes up for faster than light travel any time soon. Just know it may not be as impossible as thought.