ON AN INTER-GALACTIC HIGHWAY

Claustrophobic in the cosmos? Speed of light slowing you down? Sick of being stuck in the solar system? Mike Ross journeys to the fringes of science in search of some very quick fixes.

In the first issue of MASSIVE, Mike Ross calculated that it is 442 million times more likely that you will win Lotto Powerball than it is that we occupy the only liveable planet in the universe. Though these odds may sound appealing, we’ll have to be quick to purchase our ticket. We’ll have to move faster than light.

The light from our sun takes around about eight minutes to reach Earth. Unfortunately, the light from Proxima Centauri, our nearest stellar neighbour, takes some four years to get here. This simple reality in itself makes the conclusion all but unavoidable – if man truly wishes to breach the confines of our solar system, let alone our galaxy, it is essential we have an ability to travel much faster than our current trajectory of spacecraft development will ever allow for.

Because even if we were to build a ship capable of travelling at the speed of light, an eight-year round trip to the nearest solar system would be a very big ask for even the most dedicated of astronauts, let alone for the first waves of inter-stellar migrants.

Something would need to be very wrong with Earth before such journeys would start to seem an even remotely practical proposition on a large scale. Never mind that we wouldn’t want to move to Proxima Centauri’s inhospitable system anyway.

No, if inter-stellar travel is ever to become an unexceptional component of the human experience, then clearly travel at speeds beyond that of light is a necessity. This reality becomes all the more apparent when one considers that even travelling at the speed of light, it would take the crew  of a spaceship roughly 4000 generations just to get from one end of our galaxy to the other. There is therefore very little point in man pursuing travel at the speed of light – we need to be setting our sights on going much, much faster!

Super-luminal velocity (or faster than light travel) is considered a major no-no in traditional conceptions of physics. Then again, some people once believed that if cars travelled faster than 80 miles per hour (128km/h) the occupants would be unable to breathe. Science fiction has regularly used faster-than-light travel as a vehicle, and accordingly it is science fiction that has offered society its popular conceptions of how such travel might come about.

Two of the most widely popularised pathways to super-luminal travel are ‘warp  drives’, of the types depicted in Star Trek and Star Wars, and wormholes, like those portrayed in Star Gate and somewhat more convincingly (and menacingly) in Event Horizon. Though neither of these methods is theoretically impossible, there are some significant physical issues that make it highly unlikely that we will ever achieve inter-stellar, let alone inter-galactic, travel with either

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WARP DRIVES
A warp-drive device creates a space-time bubble around the craft that contains it. The spaceship is stationary in relation to the space surrounding it in the bubble. However, to an observer it would appear to be travelling almost incomprehensibly fast. Using the counter-gravitational properties of negative energy, a warp drive condenses the space-time structure in front of the bubble, essentially bringing its contents closer to their destination. This condensing of space-time at the front of the bubble is matched to a proportionate expansion of space-time to its rear. As is depicted in science fiction, a craft powered by a warp drive would always have to programme-in its course before entering a warp bubble, because there could be no communication from the inner layer to the outer layer of the bubble without breaking the principle of cause and effect – the rule that prevents time travel to the past, and one of the very few ‘rules’ that appears to apply within both General Relativity and Quantum Mechanics.

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WORMHOLES
Like a warp drive, a wormhole utilises negative energy to abbreviate space-time.  Space-time as we experience it is based around all matter possessing positive energy. It is this positive energy that creates the gravity that gives space-time its curvature. If we were to create enough negative energy we could potentially develop a device that uses repulsive gravitation to ‘fold’ two points in space together. Though, in the strictest sense, travelling through the wormhole would not amount to achieving super-luminal velocity, the result would be the same for practical purposes, as it would allow us to get from point A to point B far more quickly than light travelling a curved path through space would make the same journey.

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THE BIG ‘NEGATIVE’
As both wormholes and warp drives are both theoretically possible, the same theories with which their possibility has been proven can also be applied to figuring out the amounts of energy required to achieve either. This is where the big problem with these ideas becomes very apparent.

Within the observable 4.6% of the universe, there is always slightly more positive energy than there is negative. This is down to phenomenon called quantum interest, in which any negative energy created must always be ‘repaid’ with slightly more positive energy. In practical terms, this means that vast amounts of energy would be required to produce enough of the negative energy upon which both warp drive and wormhole technologies rely.

How vast an amount of energy? To create a one-metre diameter wormhole between Earth and Proxima Centauri would require the total energy produced by 10 billion stars in a year. As for creating a wormhole large enough for The Enterprise to travel through – unfortunately, barring a dark matter surprise, this would require fractionally more energy than exists in the universe. It is therefore highly unlikely that humans or spaceships will ever travel using wormhole or warp-drive technologies.

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SO HOW MIGHT WE DO IT THEN?
Though two of science fiction’s favourite options might have been eliminated as practical means of inter-galactic transportation, more enthusiastic Star Trek followers may well have noted that teleportation has not yet been discussed.
One reason for this is simply that teleportation of the Star Trek variety is not a super-luminal technology because it breaks down matter into wave forms, the transmission of which cannot exceed the speed of light. This is why Scotty is only able to beam Kirk up while The Enterprise is in near orbit. It does, however, offer a partial principle for the formulation of a practical super-luminal travel plan.

The idea that matter may be broken down, ‘transmitted’, and reassembled somewhere else, could potentially be a key principle in the construction of a technology that could facilitate our species’ expansion outwards into the universe. One possibility as to how such a technology might move into the realm of the super-luminal may lie in a coupling Gunter Nimtz’s contentious conception of quantum tunnelling to Ray Kurzweil’s assessments of the capacities of ‘intelligent’ nanotechnology.

Quantum tunnelling in this context can most easily be described as a phenomenon in which a particle jumps from point A to point B without spending any detectable time in the gap (the quantum tunnel) between the points. The particle still passes through the gap (as in the analogy, the ‘ball’ eventually goes through the ‘wall’), but rather than being a normal, positively charged particle with mass, while in the tunnel it becomes a virtual particle (or the ball disappears). A virtual particle has been named such on account of it being unobservable while in the tunnel, although we know it was in the tunnel on account of it emerging on the other side.

Within the gap, the virtual particle exists both nowhere and everywhere simultaneously. Nimtz claims that because no time is expended in the gap, a particle that passes through the tunnel will get from point A to point B faster than light would cover the same distance. This form of quantum tunnelling exists naturally, and is what, thankfully for life on Earth, allows particles to escape from the gravitation of the sun. At present, the longest man-made quantum tunnels at are only about a metre long, but there is no reason to believe we shouldn’t be able to tunnel further in the future.

In order for quantum tunnels to be of any use to us, we need to be able to make more intelligent use of the matter small enough to pass through them. This is one of the many ways in which the trajectory of our advances in nanotechnologies is very exciting. If, true to Kurzweil’s predictions, we gain the ability to encode ever more data on a sub-atomic level, then the possibility of a form of super-luminal teleportation becomes tantalisingly real.

Star Trek-style teleportation essentially sends the ‘code’ of the traveller in a waveform and then reassembles the person out of matter available at their destination. As long as carbon is available then we have the initial building blocks required to assemble a human. We just need to master the code. Were we to be able to encode a human into a data package small enough to be transmitted through a quantum tunnel, we would be well on our way to travelling the universe.

The issue that would remain relates to where our quantum data packets would tunnel to. To jump from point A there needs to be a point B. Here the answer could lie in a Kurzweilian assessment of the potential of nanotechnology.

Imagine the relationship between a highway and service stations. To travel the length of a long highway you will need to stop to refuel. Now imagine that the highway leads to Proxima Centauri and that the service stations are the nano-engineered relay points that the data packet could jump between. The difference between this inter-stellar highway and the roads of today is that a traveller on the inter-stellar highway would only spend time at the ‘service stations’ with no time elapsing on the road between them. Once such a highway was built, data travelling along it could cover distances much faster than light, even if it does have to make rest stops.

This still leaves a couple of big questions: how do we put the relay stations in place? And how could we get them into position faster than light? If we couldn’t answer the second of these we would be looking at least at a 4000-generation build time just to get our highway across our galaxy.

Thankfully, here there are two solutions that spring to mind. The first is a randomised process, in which we encourage groups of ‘intelligent’ particles to jump to wherever they want. When they arrive ‘somewhere’ they assume the form of the relay station they are programmed to be, and transmit their position to us. When we have established a sufficiently large network of relay stations, we can then begin plotting tunnelling paths between them.

The second approach is far less ‘random’ and allows for the re-admission of wormholes into the discussion. While the energy requirements of wormholes rule them out for human-sized travel, achieving the energy requirements of a one-atom-diameter tunnel would be far more plausible. Were we to use microscopic wormholes to deliver the components of the relay stations into predetermined positions, we could conceivably build our inter-stellar highway very quickly. With this type of approach, wormholes may well prove to be the ‘boring machines’ that allow for the establishment of an inter-galactic quantum tunnel system through which our coded human forms could travel the universe.

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MILITARY SPENDING VERSUS SPACE SPENDING
Many who oppose investment in space technologies do so out of a well-intentioned belief that it is irresponsible to be spending money on flights of fancy while appalling poverty still exists in many parts of the globe. I certainly wouldn’t suggest that we should cut aid budgets to fund our travel to other worlds. In fact, I’d suggest investment in space can have quite the opposite effect.

Success in space will encourage us to solve the problems on Earth more globally and more equitably. It is not mere coincidence that the decade America went to the moon was also the decade that the civil rights movement demanded that their society’s morality keep pace with its technology. The first trip to the moon might have been ‘a giant leap for mankind’, but in the context of the Cold War, it was an achievement that belonged to America first and humanity second.
Expense should ensure our coming trips to other worlds will ‘belong’ to a broader swathe of humanity, and hopefully all humanity’s sense of fraternity will be as lifted by them as America’s once was.

Where the money could come from is clearly demonstrated below. Today, man’s often amazing achievements in space come against the backdrop of a sad set of priorities. Based on the current rate of space travel technology development at existing levels of investment, if each of the major economic powers were to allocate but 25% of their annual military budgets to space exploration, mankind could very realistically develop the technology required to leave this solar system by the end of this century. Surely this is a more inspirational use of money than blowing one another up. An inter-galactic nano-highway might well be many centuries of development down the line, but then again, surely the universe is a lottery worth entering!