![]() This 2–dimensional representation shows how positive mass curves spacetime (left side, blue earth) and negative mass curves spacetime in an opposite direction (right side, red earth). Proxima Centauri here we come, right? Unfortunately, Alcubierre’s method of compressing spacetime had one problem: it requires negative energy or negative mass. Alcubierre showed that the warp drive from “Star Trek” was in fact theoretically possible. In theory, this approach does not contradict the laws of relativity since you are not moving faster than light in the space around you. Then, moving through spacetime at your maximum speed of one meter per second, you would be able to reach point B in about one second. However, let’s say you could somehow compress the space between you and point B so that the interval is now just one meter. If you are standing at point A and can travel one meter per second, it would take 10 seconds to get to point B. So, what does that mean? Imagine the distance between two points is 10 meters (33 feet). In 1994, Miguel Alcubierre, a Mexican theoretical physicist, showed that compressing spacetime in front of the spaceship while expanding it behind was mathematically possible within the laws of General Relativity. What if a starship could compress space in front of it while expanding spacetime behind it? “Star Trek” took this idea and named it the warp drive. Early science fiction writers John Campbell and Asimov saw this warping as a way to skirt the speed limit. This curvature is what you feel as gravity and why many spacefaring heroes worry about “getting stuck in” or “falling into” a gravity well. General relativity also describes how mass and energy warp spacetime – hefty objects like stars and black holes curve spacetime around them. General Relativity states that space and time are fused and that nothing can travel faster than the speed of light. ![]() Physicists’ current understanding of spacetime comes from Albert Einstein’s theory of General Relativity. AllenMcC/Wikimedia Commons Compression and expansion This 2-dimensional representation shows the flat, unwarped bubble of spacetime in the center where a warp drive would sit surrounded by compressed spacetime to the right (downward curve) and expanded spacetime to the left (upward curve). Two recent papers made headlines in March when researchers claimed to have overcome one of the many challenges that stand between the theory of warp drives and reality. Warp drives are theoretically possible if still far-fetched technology. Another approach – familiar to “Star Trek” fans – is warp drive technology. ![]() Some characters – like the astronauts in the movies “Interstellar” and “Thor” – use wormholes to travel between solar systems in seconds. I am now a theoretical physicist and study nanotechnology, but I am still fascinated by the ways humanity could one day travel in space. As a kid, I read as many of those stories as I could get my hands on. In Issac Asimov’s Foundation series, humanity can travel from planet to planet, star to star or across the universe using jump drives. But so far, faster-than-light travel is possible only in science fiction. If humanity ever wants to travel easily between stars, people will need to go faster than light. It would take just 20 seconds to go from Los Angeles to New York City at that speed, but it would take the solar probe about 6,633 years to reach Earth’s nearest neighboring solar system. The fastest ever spacecraft, the now- in-space Parker Solar Probe will reach a top speed of 450,000 mph. It is about 4.25 light-years away, or about 25 trillion miles (40 trillion km). We show that a class of subluminal, spherically symmetric warp drive spacetimes, can be constructed based on the physical principles known to humanity today.The closest star to Earth is Proxima Centauri. Therefore, any warp drive requires propulsion. Conceptually, we demonstrate that any warp drive, including the Alcubierre drive, is a shell of regular or exotic material moving inertially with a certain velocity. We present the first general model for subluminal positive-energy, spherically symmetric warp drives offer superluminal warp-drive solutions that satisfy quantum inequalities provide optimizations for the Alcubierre metric that decrease the negative energy requirements by two orders of magnitude, and introduce a warp drive spacetime in which space capacity and the rate of time can be chosen in a controlled manner. ![]() In this study, we have developed a model of a general warp drive spacetime in classical relativity that encloses all existing warp drive definitions and allows for new metrics without the most serious issues present in the Alcubierre solution. For this reason, the Alcubierre warp drive has been widely considered unphysical (not possible per physics). It allows for superluminal travel at the cost of enormous amounts of matter with negative mass density. The Alcubierre warp drive is a novel solution in general relativity. ![]()
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