No universo ficcional de Star Trek, a dobra espacial (ouwarp drive em inglês) é uma forma de propulsão mais rápida que a luz (FTL). Geralmente, ela é representada como sendo capaz de impulsionar uma espaçonave ou outros objetos a muitos múltiplos da velocidade da luz, ao mesmo tempo que evita os problemas associados adilatação do tempo. Ela também é apresentada no jogo de computador Stars! e no filme Starship Troopers, bem como nos jogos de computador StarCraft e Eve Online. Não é capaz, via de regra, de criar uma viagem instantânea entre dois pontos a velocidade infinita, como tem sido sugerido em outras obras de ficção científicausando tecnologias teóricas tais como hiperdrive, salto hiperespacial e Motor de Improbabilidade Infinita. Ela é denominada FTL (Faster Than Light) nos romancesTitan. Uma diferença entre a dobra espacial (ou warp drive) e o hiperespaço é que, diferentemente do hiperespaço, a nave não entra num universo ou dimensão diferente, ela meramente cria uma pequena "bolha" de tempo-espaço normal ao seu redor. Naves em dobra podem interagir com objetos no espaço normal. (In case you need another reason to love science in 2013) Warp Speed, Scotty? Star Trek's FTL Drive May Actually Work There's a loophole in Einstein's general theory of relativity that could allow a ship to traverse vast distances in less time than it would take light. The trick? It's not the starship that's moving — it's the space around it. In fact, scientists at NASA are right now working on the first practical field test toward proving the possibility of warp drives and faster-than-light travel. Maybe the warp drive in "Star Trek Into Darkness," the franchise's latest film opening this week, is possible after all. According to Einstein's theory, an object with mass cannot go as fast or faster than the speed of light. The original "Star Trek" series ignored this "universal speed limit" in favor of a ship that could zip around the galaxy in a matter of days instead of decades. They tried to explain the ship's faster-than-light capabilities by powering the warp engine with a "matter-antimatter" engine. Antimatter was a popular field of study in the 1960s, when creator Gene Roddenberry was first writing the series. When matter and antimatter collide, their mass is converted to kinetic energy in keeping with Einstein's mass-energy equivalence formula, E=mc2. In other words, matter-antimatter collision is a potentially powerful source of energy and fuel, but even that wouldn't be enough to propel a starship to faster-than-light speeds. Things with mass can't move faster than the speed of light. But what if, instead of the ship moving through space, the space was moving around the ship? Space doesn't have mass. And we know that it's flexible: space has been expanding at a measurable rate ever since the Big Bang. We know this from observing the light of distant stars — over time, the wavelength of the stars' light as it reaches Earth is lengthened in a process called "redshifting." According to the Doppler effect, this means that the source of the wavelength is moving further away from the observer — i.e. Earth. So we know from observing redshifted light that the fabric of space is movable. Alcubierre used this knowledge to exploit a loophole in the "universal speed limit." In his theory, the ship never goes faster than the speed of light — instead, space in front of the ship is contracted while space behind it is expanded, allowing the ship to travel distances in less time than light would take. The ship itself remains in what Alcubierre termed a "warp bubble" and, within that bubble, never goes faster than the speed of light. Since Alcubierre published his paper "The Warp Drive: Hyper-fast travel within general relativity" in 1994, many physicists and science fiction writers have played with his theory —including "Star Trek" itself. Alcubierre's warp drive theory was retroactively incorporated into the "Star Trek" mythos by the 1990s TV series "Star Trek: The Next Generation." In a way, then, "Star Trek" created its own little grandfather paradox: Though ultimately its theory of faster-than-light travel was heavily flawed, the series established a vocabulary of light-speed travel that Alcubierre eventually formalized in his own warp drive theories. The Alcubierre warp drive is still theoretical for now. "The truth is that the best ideas sound crazy at first. And then there comes a time when we can't imagine a world without them." That's a statement from the 100 Year Starship organization, a think tank devoted to making Earth what "Star Trek" would call a "warp-capable civilization" within a century. The first step toward a functional warp drive is to prove that a "warp bubble" is even possible, and that it can be artificially created. That's exactly what physicist Harold "Sonny" White and a team of researchers at NASA's Johnson Space Center in Texas are doing right now. http://www.space.com/21140-star-trek-warp-drive-possible.html