Just how fast is?: GF Willmetts. The speed is light is finite. About 186,000 mp/sec or 300,000 km/sec depending which measuring system you use. This velocity might vary a little, depending on how close a beam of light gets to a singularity or black hole but it slows down, never goes faster. Light also does the same thing to a varying degree with liquids and transparent materials like diamond, showing how its movement is capable of being distorted but never faster. It is also one of the most dependable numbers in any measuring system in the universe. I doubt if anyone ever uses it as the basis for their measuring system itself, mostly because they would only have found out light’s speed after that was established and would be too huge to break into smaller fractions but it would be used to gauge the size of the universe. Like Pi, it’s one of the constants of the universe. If you had to describe two numbers to an alien, the speed of light would be easier to start with as it is also the means to measure celestial distances. Pi would come second because it’s a fraction properties.
If you are going to visit another star system within your lifetime, then you need to go faster than the speed of light, to achieve the necessary velocity. Of course, you wouldn’t be making a direct flight. Your navigation equipment will have to account for your velocity and that of the expanding universe to where it is supposed to be but that’s minor side issues for the present. You still have got to find a way to travel that fast.
There’s been a lot of discussion as to how faster-than-light speeds can be achieved, together with other implications. I discussed the impossibility of singularity wormholes last month. Assuming something like warp drive was possible, how would it affect the speed of light? I mean, would you be going faster than the light so how would you see anything? It would be a bit crazy that you approached such speeds and the lights went out. Then you would have to remember the rules of relativity.
Do you remember ‘Exposed’, the second episode of the ITV SF series ‘UFO’, where in an aeroplane, Dr. Doug Jackson (actor Valdek Sheybal) gave an object lesson to test pilot Paul Foster (actor Michael Billington). Throwing a pen up in the air, Jackson illustrated the point that the pen hadn’t just gone up in the air but was also moving forward at the same speed as the plane. The same applies to everything else on the plane, including light. If we do the same on a starship, then light would still move at its constant speed plus that of the vessel’s velocity as well. The speed of light hasn’t been corrupted, just seen in a different relative perspective. The same would apply to any faster than light travel…if it can be discovered. Light wouldn’t be left behind, it would still move at the same speed within any starship no matter how much faster you were travelling.
Having got that out of the way, this doesn’t explain how you can get a spaceship to travel faster than the speed of light but it does explain why light’s own velocity isn’t corrupted by doing so. Gradually building up acceleration to such speeds could be achieved and providing you keep going in one direction, wouldn’t do damage to the human body because, as the example above showed, everything involved would be moving at the same speed. It only becomes dangerous if you change direction suddenly or come to a rapid halt. The problems centre on not only accelerating but decelerating on arrival, both of which would take a long time. Combined with this is that the most energy thrust can achieve is up to the speed of light as its limit.
If you are planning to beat the speed of light then you’re going to have to look to see if Mother Nature has been there first because with all science, we have always copied from it. Therein lies the problem as last year, it was proven that even neutrinos don’t go faster than the speed of light and that’s the only acknowledged atomic-size energy-charged particle that isn’t locked into an elemental pattern of a nucleus of protons and neutrons surrounded by an electron field. It isn’t just light but energy that shares the same problem.
This brings up a secondary problem even if faster-than-light travel were possible, namely what do you use for a power source? You would need a large power source to feed off of and to move the total mass of it and the starship. What is really required is a means of a sustained power source. An explosion between real and anti-matter isn’t that practical, let alone having enough of the latter to do anything with. Carrying an energy source like a small star, as used in Larry Niven’s ‘Known Space’ stories with the Puppeteers escaping the galaxy still brings the problem of how do you contain a star, let alone move it and they aren’t exceeding the speed of light. Something even the Puppeteers haven’t done. Even unlimited conventional power isn’t going to be enough. If we can’t be that ambitious, then selecting a small moon might be sensible. There would be enough rock to protect against cosmic radiation damage and even a small gravity field. If it contains methane or other gaseous solids then you would have a ready power supply, assuming that increased velocity doesn’t raise the temperature and evaporate it all.
Even so, there would not be unlimited time. Einstein pointed out that that as objects approaching light speed have a slower time dilation than standard reality. That would prolong your life but any contact with your home civilisation is out the window, let alone keeping in contact. Messages sent at light speed would never catch up until you start decelerating. Depending on how long it would take to slow down, you would still lose a few years. Better to hibernate the entire trip but if anything went wrong, you aren’t likely to be in a position to do anything about it. Sending any relevant information back to the original ground crew would be an impossibility as the message would not exceed the speed of light returning.
Are there any alternatives? Drawing energy from an extra-dimensional source is a frequent trope in Science Fiction but you would have to have a natural rift to draw it from before you could make use of it. Even so, it’s still energy and we’re back to square one. If any energy was that fast, we’d just face a massive incineration in its blast.
Isaac Asimov always considered bypassing our reality altogether and using hyperspace where reality was the inverse of our own ie long distances became shorter. Examples in the visual media of this were in the ‘Star Wars’ and ‘Babylon 5’ franchises that paid homage to this. In some respects, hyperspace as an extra-dimensional space is comparable to the extra dimensions as put forward regarding String Theory. For all the associated maths, there is still yet to be any physical proof to go with it. If these dimensions can be accessed then no doubt Asimov will one day have his name associated with the means to jump space. Quite what would happen to organic life going through such dimensions is anyone’s guess.
Of course, if you just stopped inertia, you could just stop moving with the flow of the expanding universe and fly in the opposite direction to the expanding universe. One thing for sure, you’d never get home again. It would also be a lot harder to anticipate arriving where some star system would be behind you, let alone hope it would be inhabitable. Also consider that the distance would be widening not decreasing, it would be doubtful if any contact with Earth could be achieved again neither.
Does that mean that we are stuck with limited space flight? Well, is it so limited? I mean, generation ships are still possible. It doesn’t necessarily mean you and your crew would reach a distant star, but certainly your children’s children would. Probably a better option than relying on sending genetic material and hoping that it can be successfully resurrected on arrival. Both of these are long term plans and short of the world ending, probably wouldn’t be considered anyway.
Of course, the reverse can still happen and aliens arrive in their own generation starships. Let’s examine that scenario. Their starship would have targeted our star system long before we existed, maybe even as far back as the dinosaur era. All they would know is that our star system has a watery world and an oxygen-based atmosphere. I doubt if they would be methane-breathers, but they might even consider Jupiter or Saturn as fuelling stations. Even so, it would be unlikely that it would be a flying visit. They might want to leave colonists and we would have to hope that they didn’t want to, intentionally or not, depose the dominate species. That’s us, by the way.
Many Science Fiction scenarios have dealt with this. Short of immortality, I doubt if they would be here for a flying visit before going anywhere else. We would both have to hope that both species were adult enough to be gracious to colonisers and inhabitants. Even this paragraph alone, has been enough for many Science Fiction stories. If there is an exchange of technology knowledge, then it would be a good exchange.
One last thing to consider is nuclear entanglement. We know that this is the possible means for teleportation, even if it hasn’t been achieved with anything larger than atomic level so far. If it was discovered that such a link could move people automatically to another inhabited world, space no distance, then it is also a possible option. However, the first volunteers would also have to have the know-how and, hopefully, the precious machinery to allow a return trip or we would never know it worked. Even so, other than materialising on a habitable world, there would be little choice where you could go, although one would hope that we would all end up at the same place. One would only hope that such simultaneous transportation wouldn’t have a time lag or be susceptible to momentum forces which would destroy the subjects on arrival.
The importance of space travel should not be neglected. We have no proof that there are sentient species elsewhere in the universe but confining the only species we know to one planet that could be wiped out by natural disaster or of its own making is hardly self-serving. To colonise at least one or more other worlds would prevent extinction. Although this might not seem so important any more to many people, this is not a goal that should not be neglected if for no other reason than prove that sentience isn’t an evolutionary mistake. If we are to prove ourselves better than that, then we must see this as a goal to our existence.
© GF Willmetts 2012
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My thanks to Rod MacDonald for suggestions in the making of this article.