Most people have a real problem with the idea of time travel, and the so-called ‘grandfather paradox’ encapsulates why the idea appears to assault common sense so strongly. The idea is that if a young man was able to travel back from the present time to, say, 1950, he might kill, or cause his grandfather to be killed before his own father was born. If this were to happen, it would mean that he could not exist and therefore could not have killed his grandfather. The problem just goes around in apparently impossible circles. The only solution appears, at first view, to be to consider all such journeys as utterly impossible – if for no other reason than to save us from terminal confusion!
However, Deutsch and Lockwood are not so easily fazed and they remain unconvinced about the need to protect our sensibilities from issues of reality just because laypeople tend to become confused. In an article published in Scientific American they discuss another apparent time paradox that deals with the possibility that even knowledge does not seem to require a beginning.
They refer to the grandfather-killing scenario as being an ‘inconsistency paradox’ and then they discuss another type of apparent time-traveller violation of logic that they call a ‘knowledge paradox’. This is an apparent violation of the principle that knowledge can only come into existence as a result of problem-solving processes, such as biological evolution or human thought. In the example, they talk about a hypothetical art critic who goes back in time to visit a famous artist from the previous century who, the critic realizes, is only producing very mediocre work. The time traveller shows the painter a book containing reproductions of his later and greater works, which he then proceeds to carefully copy in every detail with oil paints onto canvas. This means that the reproductions in the book exist because they are copied from the paintings and the paintings exist because they were copied from the reproductions. So, where did the inspiration come from?
‘This kind of puzzling paradox,’ say Deutsch and Lockwood, ‘once caused physicists to invoke a chronology principle that, by fiat alone, ruled out travel into the past.’ But they believe that travelling into the past does not violate any principle of physics, however much it seems counterintuitive to the average person. Furthermore, the Oxford duo state that quantum-mechanical effects actually facilitate time travel rather than prevent it, as some scientists once argued.
They explain the basics of the concept of time by pointing to Einstein’s special and general theories of relativity where three-dimensional space is combined with time to form four-dimensional space-time. Within this, everyone’s life forms a kind of four-dimensional ‘worm’ in space-time, with the tip of the worm’s tail corresponding to their birth and the top of the head to the person’s death. The line along which the ‘worm’ lies is called the person’s (or object’s) ‘worldline’ and each moment of time is a cross section of that worldline.
Einstein’s general theory of relativity predicts that massive bodies, such as stars and black holes, distort space-time and bend worldlines. This is believed to be the origin of gravity – and, for example, the Earth’s worldline spirals around that of the Sun, which in turn spirals around that of the centre of our galaxy. Deutsch and Lockwood propose that if space-time becomes really distorted by gravity some worldlines would become closed loops where they would continue to conform to all the familiar properties of space and time in their own locality, yet they would become corridors to the past. They state:
‘If we tried to follow such a Closed Timelike Curve (or CTC) exactly, all the way around, we would bump into our former selves and get pushed aside. But by following part of a CTC, we could return to the past and participate in events there. We could shake hands with our younger selves or, if the loop were large enough, visit our ancestors. To do this, we should either have to harness naturally occurring CTCs or create CTCs by distorting and tearing the fabric of space-time. So a time machine, rather than being a special kind of vehicle, would provide a route to the past, along which an ordinary vehicle, such as a spacecraft, could travel.’42
So, world-class physicists like Professor Deutsch can conceive of potentially giant spacecraft voyaging backwards in time. Perhaps such craft could be filled with chronobots that could even self-replicate to take on a task that might take hundreds of thousands, or even millions, of years. Building an object the size of the Moon with pre-programmed orbital requirements is unlikely to be a quick exercise. But time would literally be on their side.
There are various ideas about how these time-travel enabling CTCs might be formed. The mathematician Kurt Gödel found a solution to Einstein’s equations that describes CTCs within a rotating Universe and they also appear in solutions of Einstein’s equations describing rotating black holes. But there are many practical problems including the evidence that naturally occurring black holes are not spinning fast enough. Maybe a technique will one day be found to increase their rotation rate until safe CTCs appear.
The physicist John A Wheeler from Princeton University has famously suggested shortcuts through space-time that he calls ‘wormholes’, and other scientists have shown how two ends of a wormhole could be moved, so as to form a CTC.
Professor Deutsch has become a champion of the many-Universes theory, first put forward by Hugh Everett III in 1957, where everything that can happen does happen. For this reason, the supposed paradoxes of time travel simply do not exist. In the scenario where the man kills his grandfather, he does not exist in the one single Universe where the murder is committed, but he does in the ones where he fails to assassinate his forebear.
Deutsch and Lockwood conclude that there is no scientific objection to time travel, saying in their article:
‘The idea that time travel paradoxes could be resolved by “parallel Universes” has been anticipated in science fiction and by some philosophers. What we have presented here is not so much a new resolution as a new way of arriving at it, by deducing it from existing physical theory… These calculations definitively dispose of the inconsistency paradoxes, which turn out to be merely artifacts of an obsolete, classical worldview.’
They appear to be suggesting a loop in time that has a twist in it so that contact is made with a near identical parallel existence, through which the time traveller can arrive at a time and place that always has them present.
Their thought-provoking article concludes with the authors pointing out that science says time travel is theoretically possible. As a result, the onus is on those who wish to argue otherwise to prove their case:
‘We conclude that if time travel is impossible, then the reason has yet to be discovered. We may or may not one day locate or create navigable CTCs. But if anything like the many-Universes picture is true – and in quantum cosmology and the quantum theory of computation no viable alternative is known – then all the standard objections to time travel depend on false models of physical reality. So it is incumbent on anyone who still wants to reject the idea of time travel to come up with some new scientific or philosophical argument.’
And many experts agree. Physicist, Matt Visser of Victoria University of Wellington, has compiled a short list of the time travel opportunities that have turned up since Einstein showed us how to warp space-time. He has said that Einstein’s general theory of relativity not only allows time machines to exist, it is ‘completely infested with them’.
Others fear the concept of time travel, even though they have not been able to demonstrate that it cannot be done. ‘I think most of us would like to get rid of time machines if we possibly could,’ says Amanda Peet of the University of Toronto. ‘They offend our fundamental sensibilities.’
The only argument that has been made against time travel comes from the famous Cambridge phycisist, Stephen Hawking, in the form of his ‘chronology protection conjecture’. This suggestion boils down to the notion that the Universe might have a built-in time cop, so whenever anyone is on the verge of constructing a working time machine the time cop turns up and shuts the operation down before it has a chance to damag
e the past. However, there are no time cops evident in the laws of physics, so, at the moment, the chronology protection conjecture is simply wishful thinking.
As far as our scenario is concerned, humans exist because, at some future point, we will return to the time when our planet was a young lump of unstratified matter and then we shall make the Moon.
Once complete, our Moon worked its magic and life began, evolving eventually into an intelligent, ten-fingered species that uses Megalithic and metric units. The message had to be built into the very nature of the structure or else we would miss the cue to understand what we need to do.
But how can we do it and when will we do it?
Ronald Mallett, a Professor of Theoretical Physics at Connecticut University, already believes he has found a way to create a CTC or time machine using light. He has identified that a circulating beam of light, slowed right down to a snail’s pace, may well be the key to the door of time travel because, although light has no mass it does bend space. The realization that time, as well as space, might be twisted by circulating light beams caused Mallett to team up with other scientists at Connecticut University in 2001, with the intention of building a prototype, saying, ‘With this device time travel may become a practical possibility.’
Mallett decided that if he added a second light beam, circulating in the opposite direction to the first, it would increase the intensity of the light enough to cause space and time to swap roles. Inside the circulating light beam, time runs round and round, and, what to an outsider appears to be time becomes like an ordinary dimension of space. A person walking along in the right direction could actually be walking backwards in time – as measured outside the circle. So after walking for a while, you could leave the circle and meet yourself before you have entered it.
However, it turns out that the energy needed to twist time into a loop is enormous, and when Mallett reviewed his progress he realized that the effect of circulating light depends on its velocity: the slower the light, the stronger the distortion in space-time.
By strange good fortune, Lene Hau, a phycisist at Harvard University, has slowed light from the usual 300,000km per second to just a few metres per second, and almost frozen its progress completely. Mallett was ecstatic saying, ‘The slow light opens up a domain we just haven’t had before. All you need is to have the light circulate in one of these media.’
Maybe current scientists will crack the problem of time travel but it seems logical to expect the necessary instructions to be contained in the deeper layer of the Moon’s message. However, it seems likely that black holes may be at the root of the technology required.
The black holes of deep space are the gravitational remains of dead stars. They are super-dense, bottomless pits in both space and time that are capable of sucking in almost infinite amounts of material, including light. Everything a black hole swallows gets compressed into an unimaginably tiny central region called a ‘singularity’ in which the atoms are crushed into an unmoving whole. If the Earth were to become as dense as a black hole, it would be smaller than a golf ball. (And they say you can’t compress water!)
There seems to be no way to get any information about what is happening inside a black hole, as even light is trapped inside. However, Cambridge physicist Stephen Hawking proposed a way in which black holes do radiate matter and slowly dissipate until they eventually disappear in a final mega-burst of radiation.
Amazingly, scientists are becoming increasingly confident that they will be able to create black holes on demand using the new atom-smashers due to come on line in 2007. It is believed that the new Large Hadron Collider (LHC) being built astride the Franco-Swiss border west of Geneva by the European Centre for Nuclear Research (CERN) will be able to create black holes at the rate of one per second. The LHC is an accelerator which will bombard protons and antiprotons together, with such a force that the collision will create temperatures and energy densities not seen since the first trillionth of a second after the big bang. This should be enough to pop off numerous tiny black holes, with masses of just a few hundred protons. Black holes of this size will evaporate almost instantly, their existence detectable only by dying bursts of Hawking radiation.
This work is at an early stage but it may well prove to be the beginnings of a platform that could drive the search for the technology to enable time travel.
If humans from our future did travel to the distant past to create the incubator that would produce our own species, it does make complete sense of the message left to us. We have to imagine that our ability to complete such an awesome task must be hundreds or even thousands of years ahead of our current level of capabilities. However, what if the instructions of how to proceed were contained inside the message itself? If this was the case, the development time might be cut to a minimum.
Maybe a question we should be asking ourselves is why the message was so carefully timed to reveal itself at this particular time. Could it be that we have so far only seen what is little more than a ‘waving flag’ to alert us to a greater message that tells us exactly what must be done in order to fulfill our own destiny? Maybe the central pattern revealed by the mutual orbits of the Earth and its Moon and, quite separately, by the relative sizes of 366.3 x 27.3 = 10,000 is the most fundamental key of all.
At this stage there are two entirely separate questions that need to be answered:
To what are we to apply the cipher?
If humans created the Moon as an incubator for life, where did the seeds for germination come from?
The answer to both final elements of this ultimate riddle may well rest in the same place: DNA.
The secrets of the Genome
The Human Genome Project, completed in 2003, was a thirteen-year mission to unravel the secrets of the minute data store that carries all the information needed to make a human being, what we call DNA. The key goals of the project were to:
Identify all the genes in human DNA, of which there are believed to be approximately 20,000–25,000
Determine the sequences of the three billion chemical base pairs that make up human DNA
Professor Paul Davies has published an idea that strikes a real chord with the findings laid out in this book. He does not criticize the people from SETI for constantly sweeping the skies with radio telescopes, in the hope of stumbling across a signal from deep space, but he is realistic about the chances of success. He points out that it is inconceivable that aliens would beam signals at our planet continuously for untold aeons, merely in the hope that one day intelligent beings might evolve and decide to turn a radio telescope in their direction. And if the aliens only transmit messages sporadically, the chances of us tuning in at just the right time are infinitesimal.
However, he does not write off the idea of contact: ‘But what if the truth isn’t out there at all? What if it lies somewhere else? Now may be the time to try a radically different approach.’43
Davies uses the idea we have already reported of a ‘set-and-forget’ technique of communication, whereby the information content of the message may have to survive for hundreds of millions of years. He acknowledges that a conventional artefact placed on the Earth’s surface would be almost certainly overlooked, even if it did somehow survive. He then suggests that an altogether better solution would be: ‘…a legion of small, cheap, self-repairing and self-replicating machines that can keep editing and copying information and perpetuate themselves over immense durations in the face of unforeseen environmental hazards.’
This sounds like pure science fiction but he continues by saying: ‘…Fortunately, such machines already exist. They are called living cells.’
What a brilliantly simple idea. We have already established that large sections of the scientific community are openly saying that DNA absolutely could not have spontaneously arrived – it must have been designed. So, why would the manufacturer not use it to contain a message?
Is it possible? Is there spare space in there for a message?
&n
bsp; As Paul Davies confirms, the cells in our bodies, and anything else that lives for that matter, contain messages set out billions of years ago. He also says that the idea that aliens have deliberately hidden messages inside DNA has been ‘swirling around’ for a few years, and has been championed in recent times by the Apollo astronaut Rusty Schweickart. But, says Davies, on the face of it, there is a serious problem.
Living cells are not completely immune to change, and mutations introduce random errors that become stored as information, and, over a long enough time span, they would turn the original message into ‘molecular gobbledygook’. Davies then reminds us that there is so-called ‘junk’ DNA: sections of the genome that seem to serve no useful purpose. These areas could be loaded with messages without affecting the performance of the cells and some parts of that junk DNA are in highly conserved regions that are therefore relatively safe from degradation.
When a team of genomic researchers at the Lawrence Berkeley National Laboratory in California presented their own findings in June 2004, the audience gasped in unison. Those listening, simply could not believe what they were hearing from Edward Rubin and team who were reporting that they had deleted huge sections of the genome of mice without it making any discernable difference to the animals. The result was truly amazing because the deleted sequences included what is known as ‘conserved regions’, which were previously assumed to have been protected because they contained vital information about functions.
To find out the function of some of these highly conserved non-protein-coding regions in mammals, Rubin’s team deleted two huge regions of DNA from mice, containing nearly 1,000 highly conserved sequences shared between humans and mice. One of the removed chunks was 1.6 million DNA-bases long and the other was over 800,000 bases long – which should have caused the mice to have serious problems.
Who Built the Moon? Page 19
