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Go to CuriosityStream.com/SciShowSpace to start streaming thousands of documentaries and nonfiction TV shows. [♪ INTRO]. According to the laws of physics, nothing can travel faster than the speed of light, which is a bummer because that means there’s stuff in space we will never get to visit.

So scientists have always looked for loopholes to that rule. A proposed one is a theoretical Star Trek-like warp drive that lets you go faster than light without actually moving faster than light. This is a weird exception that’s always been mathematically possible, but physically impossible. … But we could now be one small step closer.

You see, the rule about not going faster than light only applies to things with mass, which is most things that we know of! But that rule does not apply to space that is surrounding an object, since space does not have mass. Einstein’s theory of general relativity tells us that space can be stretched, distorted, or warped.

A way to warp space is with extreme gravity caused by things like planets, stars, and black holes. And gravity can hugely distort and warp space like stretched rubber. But this is a problem for building, like, a spaceship that runs on warped space.

Warping something with the gravity of a black hole would just, ya know, tear the ship to shreds! So in 1994, physicist Miguel Alcubierre hypothesized a way to ‘cheat’ this system. The trick in his model was to use huge masses to make a bubble of warped space surrounding a patch of normal un-warped space.

So you could put a spaceship inside, and it would reach a faraway location faster than light would, without getting all warped and shredded to pieces. And theoretically, this shouldn’t break any physical laws, because the spaceship itself would not move faster than light. It’s the space around it doing the heavy lifting, all of which should be allowed.

But designing the warp bubble was only the first step. The next step was to work out how much and what kind of masses you would need to warp the spacetime fabric to make the bubble. Turns out, you would need more mass than currently exists in the visible universe.

Which is, you know, a lot, but it gets worse than that. The whole bucket of mass also needs to be negative mass. And if these negatives masses were to exist, which is all speculative, they would, you know, violate physics law, like Newton's second law of motion, which says that something will accelerate in the same direction as the net force applied.

If you push something with negative mass it won't move away from you, it will move towards you! That’s what we mean when we say that it breaks physics law. So warp drives were sort of stuck because as far as we know, negative masses do not exist in the natural world.

But another important step came in 2021, when researcher Erik Lentz published a study claiming to have solved the negative mass problem. He proposed a theoretical model using only normal, positive mass to get the same effect as Alcubierre’s original idea, inspired by a kind of self-sustaining wave in nature called a soliton, which moves while maintaining its shape and velocity. He tested multiple configurations using positive masses and found that by arranging masses into the shape of a polygon, it warped the space into a moving bubble.

Which could be around an un-warped patch of space, just like in Alcubierre’s version. This polygon shape also placed the gigantic masses around the ship to avoid crushing the interior. So the negative mass problem seems to have been solved.

In theory, mathematically anyway. But we are still left with the problem of using more mass available than in the visible universe to make the warp drive work. Thankfully, Lentz’s new idea needs ‘only’ a couple hundred times the mass of Jupiter to make this hypothetical warp drive work.

So, y’know, not the mass of the whole universe, but we will still need to keep bringing that amount down to avoid a pretty hefty gas bill on the spaceship. Other scientists, though, have argued that there is another big problem with warp drives. Researchers have only shown how to theoretically construct the warp bubble.

They didn’t actually say how to accelerate it to faster-than-light speeds. Because if something like a spaceship is moving slower than light speed, then according to Einstein’s theory of relativity, it’s impossible to accelerate it to faster-than-light speeds. The whole point of the warp drive is that it’s meant to avoid this problem, but some researchers have argued that the rule still applies to the warped space around the spaceship, putting us back at square one.

For an idea that’s always been thought impossible, that’s not bad progress. Just… don’t go looking for a weekend getaway to Alpha Centauri just yet. But an idea that is possible is learning about different science topics from home using programs handpicked by experts available with today’s sponsor: CuriosityStream.

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If you want to learn more, head over to CuriosityStream.com/SciShowSpace to find out what else you might be able to warp to. [ OUTRO ].