Associate professor at Australian Catholic University, Sam Baron
The warp drive, a futuristic way to sneak around the universe’s absolute speed limit by twisting the structure of space, was suggested by physicist Miguel Alcubierre in 1994 as a radical invention that enables faster than light travel.
It was an exciting concept — NASA’s Eagleworks laboratory has been exploring it — but Alcubierre’s suggestion was riddled with issues that appeared insurmountable. Many of these problems have now been overcome, thanks to a new paper by US-based physicists Alexey Bobrick and Gianni Martire, which has sparked a lot of interest.
However, while Bobrick and Martire have de-mystified warp technology successfully, their findings indicate that, for the time being, the faster-than-light flight will remain out of control for humans.
However, there is a bright lining: warp technology can have far-reaching implications beyond space travel.
Is it possible to travel around the universe?
General relativity, Einstein’s crowning accomplishment, is where the origin of warp drives begins. The equations of general relativity describe how spacetime, the very structure of life, twists in response to the presence of matter and energy, explaining how matter and energy travel.
Two laws of general relativity constrain interstellar transport. To begin with, nothing can go faster than the speed of light (around 300,000 km per second). Even at this incredible pace, it will take us four years to reach Proxima Centauri, the closest star to our own.
Second, a clock on a spacecraft traveling at near-light speed will slow down compared to a clock on Earth (this is known as time dilation). You are assuming a steady rate of acceleration, which allows for interstellar flight. Within one’s lifespan, one will travel 150 light-years to a distant star. By the time you return, the catch is that more than 300 years will have passed on Earth.
Hope for the future
Alcubierre was brought in to help. He claimed that general relativity’s mechanics allowed for “warp bubbles,” or regions in which matter and energy were structured in such a way that spacetime was bent in front of the bubble and expanded in the back, allowing a “flat” field within the drop to move faster than light.
Consider how spacetime is similar to a rubber mat to get a feel of what “flat” means in this case. In the matter and electricity, the mat curves (think of putting a bowling ball on the mat). Gravity is the ability for objects to roll onto dents made by celestial bodies such as stars and planets. A flat area is a section of the mat that has nothing on it.
A trip like this will also stop the annoyances of time dilation. One could make a round trip into deep space and be met by family and friends back on Earth.
A strange occurrence in spacetime
What is the mechanism behind Alcubierre’s device? Since math is too complicated, analogies are often used in the debate.
Consider a rug with a cup affixed to it. You’re sitting on the carpet, trying to get to the cup. You could walk over the carpet or pull it closer to you. The warp drive works by tugging on spacetime to get you closer to your destination.
However, analogies have their limitations: a warp drive does not pull you toward your destination. It compresses spacetime to shorten the journey. When you turn on the move, there’s only less rug between you and the cup.
Although Alcubierre’s suggestion is mathematically sound, it is difficult to grasp intuitively. All of that is about to change thanks to Bobrick and Martire’s job.
Bloopers from the Starship Enterprise
According to Bobrick and Martire, any warp drive must be a shell of material in a steady state of motion that encloses a flat area of spacetime. The shell’s energy changes the properties of the spacetime field beyond it.
This may not seem like much of a breakthrough, but no one knew what warp drives were mechanical before now. Their research suggests that a warp drive is, oddly, similar to a car. A car is also a shell of energy (in the form of matter) surrounding a flat spacetime field. The only difference is that getting into a vehicle does not accelerate your aging process. That, on the other hand, is what a warp drive might do.
Bobrick and Martire show a mechanism for using Einstein’s general relativity equations to find spacetimes that allow for configurations of matter and energy that behave as warp bubbles using their basic definition. This is a numerical key for locating and categorizing warp technologies.
Their thesis addresses one of the significant issues with warp drives. Alcubierre’s computer uses “negative energy” to stabilize the calculations, but we have yet to find any suitable sources of negative energy in the physical world.
Worse, Alcubierre’s system has massive adverse energy requirements. According to specific calculations, the entire known universe’s energy will be needed(Though later work reduces the number slightly).
According to Bobrick and Martire, a warp drive can be made from either positive energy (i.e., “normal”) or a combination of negative and positive energy. Nonetheless, the electricity needs will be enormous.
If Bobrick and Martire are right, a warp drive is no different from any other moving object. After all, it would be subject to the universal speed limit imposed by general relativity, and it would need to accelerate using a traditional propulsion system.
The news continues to deteriorate. Many types of warp drives will only change the spacetime inside in one direction: speeding down the passenger’s clock in the same way that makes a journey into deep space difficult.
According to Bobrick and Martire, any warp drives could fly faster than light, but only if they are produced already traveling at that pace, which is no good to any average person looking for a bit of interstellar tourism.
The big picture
Keep in mind that a warp drive can change the area of the flat spacetime it encloses. It will, for example, accelerate or decelerate a clock within the campaign.
Consider what it would be like to have such an object. If you want to put someone who is dying on ice? Please put them in a warp drive to slow down their time. A few years will pass from their viewpoint, while a hundred years will pass on Earth — enough time to discover a solution.
If you want to grow your crops in a matter of hours? Please put them in a warp drive and accelerate the clock. You’ll be gone in a couple of days, and your seedlings will be gone in a few weeks.
Many more exotic possibilities exist: by spinning spacetime within a drive, one would create a battery capable of storing massive quantities of energy.
Travelling faster than the speed of light is only a pipe dream. Warp technology, on the other hand, will be groundbreaking in and of itself.
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