Last year we heard the exciting news that NASA intends to build a fully-operational warp drive in order to achieve faster-than-light (FTL) travel. At the time we saw some snazzy pieces of concept art and were told that theoretically warp drive is possible.
Of course, theoretically is very different from practically, and although NASA may be able to solve some equations on a whiteboard, it doesn't mean we can necessarily build a vehicle that can travel faster than light.
How Far Along Is the NASA Warp Drive?
Currently, NASA considers warp drives, hyperspace drives and any other potential forms of faster-than-light travel as in the 'speculation' stage of development. In NASA development cycles, this is extremely early. In fact, it is only the next stage on from the first stage of development, 'conjecture.'
NASA Development Stages
Basically, we're a long way away from this:
Unfortunately, NASA now knows enough about FTL travel to deduce that it is essentially impossible, at least for now. It simply does not seem compatible with Einstein's Special Theory of Relativity - although others have suggested there may be ways around this, including using tachyons, wormholes, inflationary universe technology, spacetime warping, quantum paradoxes and a whole host of other methods I will not pretend to understand. More on these later.
Indeed, one of the major issues with FTL travel is that in some theories it is synonymous with time travel, which most scientists believe is ultimately far more impossible. This also opens up other issues such as creating time paradoxes, and causality violations. Those things really suck.
But Don't We Just Need To Go Really, Really Fast?
Some see breaking the speed of light as the next logical step after breaking the speed of sound - which is something humanity does pretty regularly. However, the difference of scale between these two achievements is astronomical. The speed of sound is a measly 343.2 meters a second (768 mph) and can be broken by various jet powered vehicles. Indeed, the experimental X-15 plane achieved the record-breaking speed of 4,520 mph, which is over 6 times the speed of sound and it achieved that in the 1960s.
Breaking the speed of light is very different. The speed of light is 299,792,458 meters a second, and its not simply something you can power through with a big-ass engine - even in the vacuum of space.
Furthermore, the sound barrier was broken by an object made of matter, not one made of sound. Matter consists of atoms and molecules which are connected to each other via electromagnetic fields, which is the very same stuff that light is made of.
So, in reality, breaking the speed of light requires breaking a barrier with the very same things that the barrier is made of. The real question is, how can an object travel faster than that which links its atoms?
Breaking The Theory of Relativity
The much vaunted Theory of Relativity consists of three major elements:
- Measurements of various quantities are relative to the velocities of observers. In particular, space contracts and time dilates.
- Spacetime: space and time should be considered together and in relation to each other.
- The speed of light is nonetheless invariant, the same for all observers.
In laymen's terms, the theory of relativity simple explains what one traveler "sees" relative to another who is travelling a different speed. NASA explains it like this:
Imagine you are standing with your eyes closed by some train tracks. The only information you are receiving is based on sound. When a train passes by at speed tooting its horn, it sounds like the pitch and tone of the horn changes. In reality it doesn't. The horn merely sounds different due to the Doppler shift affect. To someone on board the train, the horn would have sounded different, as the tone would have been constant. This is similar to the theory of relativity.
However, the special theory of relativity also explains that the speed of light will always stay the same, regardless of the speed of the person observing it. Since we receive ALL of our information through light and electromagnetic forces, approaching and then breaking the constant speed of light would result in a major distortion of the information we receive which would affect our perception and how matter is held together.
Another consequence of Special Relativity is the amount of energy needed to break this barrier. Energy is needed to impart movement on an object, and to move faster you need more energy. When we start to approach the speed of light, the amount of energy we need explodes to levels essentially approaching infinity.
Ultimately, all this means we can't simply power through the speed of light.
But Is There Still A Way To Achieve Interstellar Travel?
Clearly, therefore, the way to travel the vast expanses of the universe is not to simply go faster. Instead, we need to figure out some way around the laws of Special Relativity.
Firstly, there is wormhole travel. Simply speaking, wormholes are short cuts in spacetime. Although the laws of physics prevent an object moving as fast as light within spacetime, theoretically we could distort and alter spacetime, bending it and connecting two points that used to be separated. In this sense, we don't take our ship out to a point in space, but bring that point in space to us by bending it.
However, the understanding of wormholes is still in its infancy and some scientists are not sure if its a viable option. Even if it was, we would need massive amounts of energy to bend space, while we also come up against those same old pesky time paradoxes. Furthermore, making a wormhole requires energy at both ends, meaning we'd still need to somehow previously reach the further point in space.
The other option involves Alcubierre's warp-drive, which is the theoretical warp drive NASA discussed last year. This works by wrapping a ship in two rings, which distort spacetime both in front and to the rear of the vessel. In theory this will create a "hotdog shaped warp bubble," with empty space in front and behind the ship. The space behind the ship is then expanded, which will push the vessel forward at phenomenal 'speed.'
NASA cite it is analogous with walking on a moving sidewalk that is moving faster than you are. The walkway has a definite start and end in spacetime, but you will travel between those two points quicker than if you merely walked on your own. The warp engine essentially makes a very fast moving sidewalk in space.
Unfortunately, to create this effect you will need negative energy, and it is still debated in physics if such a thing even exists. Most say 'no,' with some quantum physicists saying 'maybe.' Furthermore, they're not even sure if the warp would actually move faster than light, while there are still issues with time paradoxes.
Ultimately, NASA concludes by asking: "Is there any work being done to search for these breakthroughs?"
Their answer: "Yes, but not much."