Is Faster Than Light Travel Possible? Alcubierre Warp Drive & Wormholes
Traveling Faster Than the Speed of Light: Possible?
OK, I'll admit it: I've watched a lot of Star Trek in my time. And, like most kids my age, I was captivated by the fantasy world of Star Wars as well. Both series featured a futuristic era where the stars were easily within reach. The dream of reaching other worlds has never really left me, but humanity is still 'imprisoned' on planet Earth. Is faster than light travel possible for humans, or are we stuck here for good?
We live in a universe that's governed by an infinitely complex set of rules and constraints. Light speed is one of those. The speed of light, also known as c, is a physical constant, and it doesn't just represent light. C is the maximum speed at which any particle can potentially travel, including both light particles (photons) or particles with mass. You might even recognize c as part of the famous E = mc2 equation.
If that's true, how can a warp drive be possible? Traveling faster than light should technically be impossible, but there may be ways to 'bend' the rules under which the universe operates, and travel more quickly that way.
This article will go over a few of the theoretical ways that we might travel faster than the speed of light. That includes the Alcubierre warp drive theory, and the use of wormholes such as the Krasnikov tube.
By the way, I'm going to steer clear of super technical jargon and stay pretty 'general'. If you're interested in the equations and stuff that I'm referring to, just ask and I'll point you in the right direction.
Let's get started!
How Fast Can We Go with Current Technology?
The current technology allows for what's known as 'sub-luminal' travel. In other words, it's pretty slow. Speed is a relative thing. Voyager 1, which has recently exited the Solar System, has traveled farther than any other man-made creation. It travels at a speed of around 62,000 km/h, fast enough to encircle the globe once and then some, but in space terms that's really quite slow.
For example, it will be some 40,000 years before Voyager 1 comes anywhere close to another star. That's quite a bit longer than our recorded human history!
There are some theories on how we can reach and explore other solar systems and stars using conventional technology, such as constant acceleration. If a spacecraft were to be propelled at a constant rate of 1g, you could theoretically reach nearby stars in a few years.
The Daedalus Project: This was a theoretical process to analyze ways we could reach other stars in a single lifetime using conventional technology.
The concept was simple: you create a massive starship that's mostly fuel tanks. It would make use of fusion rockets to propel itself to over 10% of the speed of light. With Barnard's Star as a target, the Daedalus spacecraft would reach the star system in around 50 years.
There are a few drawbacks, however: first, the fuel source would be mostly Helium-3, which would have to be mined from Jupiter. Secondly, it would be around the same size as the Empire State Building, so it would be a huge undertaking.
Lastly, the spacecraft would have no way of slowing down! It would literally be a 'fly-by' of Barnard's Star, so we'd only have a few days to gather whatever information we could. Then we'd have a 5.9 year wait for the data to arrive.
Solar Sail Spacecraft: You might have heard of solar sails before. They make use of either the pressure of solar wind, or the pressure of light particles to accelerate.
How can light propel a spacecraft? Give that there is no (or very little) friction in space, a very small amount of pressure can propel an object. So, by using a huge sail and a laser or particle source in the home system, a sail spaceship can reach incredible speeds.
Of course, that means that the sail must be absolutely massive, probably in excess of 100 km at the very least, and it requires a laser with an unprecedented amount of power, probably beyond what humanity can muster at this point.
It does have the capability to travel to over 10% of the speed of light, and any sail spacecraft will be unburdened by fuel storage.
What is the Alcubierre Warp Drive? Superluminal Travel at our Fingertips?
In the mid 1990s, Miguel Alcubierre developed a theoretical way in which a spacecraft might conceivably travel faster than the speed of light without breaking any of the fundamental laws of physics.
The concept is a solution that falls within the constraints of Albert Einstein's field equations. The basic idea is that you'd use negative mass, or antimatter, to 'warp' space around the spacecraft.
The idea would be to contract the space in front of the craft, and to expand it behind, effectively placing the spaceship inside a 'bubble'. By this method, the spaceship would never be travelling faster than the speed of light within the bubble, but it would be moving far faster relative to the outside world and observers.
Alcubierre theorized that this craft could achieve a relative speed of up to 10 times the speed of light using this method.
Drawbacks and Downsides:
There are considerable criticisms to this method of travel. While it's theoretically quite possible, it's fairly out of reach in practical terms. It requires a form of energy that we aren't sure how to harness, and it requires it in vast quantities. Initially, Alcubierre theorized that mass-energy equivalent to the planet Jupiter would be necessary!
There are also concerns that Hawking radiation would be present at any point the spaceship started traveling faster than the speed of light, which would fry the occupants and destroy the ship.
In fact, they're not even sure that the ship operator would be able to communicate with the front of the ship to slow it down.
In 2012, NASA decided to pursue the concept of warping space to achieve faster than light speeds. This is headed by Harold White, and they will be focusing on warping space at the smallest scale to see if the theory holds.
White and his team have also theorized that by changing the bubble into a 'doughnut shape', a great deal of energy requirement can be shaved off, meaning that far less exotic matter is needed to achieve a workable Alcubierre warp drive.
In any event, the current experiments are aimed at determining feasibility, and it's unlikely that a working 'human sized' prototype will be ready any time soon.
What is the Krasnikov Tube? Using Wormholes
Another theoretical possibility to travel faster than the speed of light without using a warp drive is making use of wormholes. Einstein theorized that space-time is curved, and because of that there could be 'shortcuts' from one area to another.
Also known as an Einstein-Rosen bridge, a wormhole is a place where space is folded in upon itself to create a link between two points.
It's tough to visualize (impossible, actually), but imagine a piece of paper with two dots on it. You can travel from dot A to dot B, but if you fold the piece of paper properly, the two dots are virtually in the same place.
The kind of wormhole needed for our purposes would be called 'transversable wormholes', because we'd need to travel through them in both directions. Current theory is pretty shaky, but it's possible wormholes existed naturally in the early universe.
Again, general relativity is preserved because at no point would anything be traveling faster than the speed of light. Instead, space itself would be folded to shorten the travel by a significant amount.
In order to hold open and maintain a wormhole, a shell of exotic matter would probably be required. Technologically, this shell would be extremely difficult to create and maintain, and it's probably some distance off in practical terms, if it's possible at all.
The Krasnikov Tube:
Developed by Serguei Krasnikov, the tube is theoretically possible but uses technology that we haven't yet achieved.
Essentially, a 'wake' must be created by traveling close to the speed of light. After traveling to a destination at close to superluminal speeds, a space-time distortion can be created, and you can travel back to the moment just after you departed.
This is a highly theoretical concept, and it's pretty unlikely to be turned into a reality anytime soon.
Warp Drive Poll:
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So When Can I Buy a Warp Drive Spaceship?
Now that you've learned that a warp drive is theoretically possible, you're probably wondering the same thing as I am: when will it be practical?
I'd estimate that we're still a long way from any sort of usable warp drive system in a starship. Consider that we're still not even sure what antimatter is, let alone how to contain it without blowing ourselves up.
I expect that the next century will see a huge explosion in space travel, and we'll start populating and mining nearby asteroids and planets. We might even see a few generational ships head for the stars, especially since our telescopes are getting better and we might start detecting a few Earth-like exoplanets any day now.
I'm sure that if you told a man living in the year 1913 that we'd walk on the moon in 56 years, he'd scoff. I'm hoping to be similarly surprised!
Thanks for reading!
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