Clearly the easy thing to do is to produce a follow-on of some sort but for a successful series that becomes more and more difficult to do both in terms of the writing and indeed of the fees demanded by the actors to reappear. In the case of Star Trek this meant that the follow-on series were spin-offs with very little real connection with the original series. Certainly the Next Generation and Deep Space Nine made little attempt to truly place themselves within the confines of the original series. Funnily enough, although Voyager was effectively in an entirely different universe, it was the one that seemed to me to be closest to the concept of the original series in exploring new worlds, new civilisations and boldly going.

Once the sequels had largely been exhausted it was time to consider prequels. In a science-fiction series these can get away with being set so many years before the original that there’s no problem with actors needing to appear younger and so Enterprise got away with an entirely different cast. The problem with that series seemed to be that it’s quite difficult to develop a plausible set of technologies that whilst more advanced than what we have now, are less advanced than what’s to come. Unfortunately in the case of Enterprise this was rather difficult as a lot of the techologies from the original series are already available now eg the communicator, electonic notepad, etc. which meant that those remaining seemed to be confined to limitations of what was shown on the original series eg the less perfected transporter, the slower warp drive, and, of course, the much grimmer decor of the ship (I suspect that this last one is what felled the series ultimately: it didn’t look science fiction enough).

Which brings us to the prequel film. Clearly the studio had decided that it was time for another Star Trek film but apparently didn’t want to pay enough to drag the various actors out of retirement. Thus we have an entirely different set of actors with pretty much the only common link to what had gone before being the name of the film. But, then, what else could they do?

It’s all so much easier to do in books….

I don’t mean the time travel aspect of it: that’ll happen one day. No, it’s the business of getting to see the President right away that’s not going to happen. Unless it’s planned for in advance.

I think the only time travel series I’ve seen which even thinks about this is Seven Days that where they arrange the codeword in advance and, of course, that’s the only way that it’s going to work. In the early days of time travel it’s likely to be similar to the early days of air travel ie there will be limitations on the distance that you can go back.

Limit that distance and it doesn’t leave you a lot of time to get in touch with the authorities, convince them that you really are from the future and for them to do whatever is necessary to prevent the disaster. Without a codeword or similar quick way of proving that you are who you say you are then it’s going to severely limit the possibilities, at least in the early days of the technology.

One final thing is worth noting and that’s if there’s some really, really major disaster that spurs on the development of time travel in order to prevent it then it would actually be necessary to put the contact mechanism in place for time travellers well in advance of time travel being possible. Ridiculous as it may seem now when time travel is considered, at best, science fiction and indeed thought of as impossible by a large number of people, it seems only sensible to put in place those contact and proof mechanisms in place just in case that major disaster is going to happen soon and time travellers do turn up in time to prevent it.

Where (or when) would you look though? The problem in identifying them is that, as we’ve discussed here before, it would be far from easy to pick them out whilst they were in our time period. There’s all kinds of reasons for that but boiling down to the fact that they’d be unlikely to have as detailed a knowledge of events in our period as would be required for them to be able to prove that they were from the future. It would be small things that would identify them and they’d be quite hard to pick out: a different way of phrasing things (but then that could just be because they were from another country), a different way of dressing (if you’ve looked in the highstreet lately you might come to the conclusion that everyone was from the future!) or different expectations (like not understanding why you had to dial a phone number instead of just asking for the person perhaps?).

However, we should be able to pick them out from the past if we narrow down the time period and look very carefully.

In that respect, perhaps the best event to consider is the sinking of the Titanic. It’s something that’s become very well known in our own time and because it sets so many precedents (eg lifeboats for everyone, manning the radio 24/7, etc.) it may remain sufficiently attractive right through to the time when someone builds a time machine. The other attraction for a potential time traveller is that it’s been very well researched so they’d know pretty much exactly where to go to see the various events and even where they needed to be to be amongst those rescued.

That last point is quite critical. If we assume that the time machine itself would need to go into the past then they would need to be amongst the survivors. Naturally, if the time machine didn’t need to go into the past then this wouldn’t apply but let’s be optimistic and assume that it needed to for now.

Think about it: this means that there’s a good chance that at least one of those survivors was from the future.

Thanks to the sheer volume of information available, it might even be possible to identify them too. What you’re looking for is someone on their own (ie exclude anyone with family on the ship or who subsequently returned to family in Europe), who wasn’t famous and who disappeared after they were rescued. An impossible task? I don’t think so: the Encyclopedia Titanica contains biographic details on all of the survivors so, in principle, it’s just a matter of working through the 712 survivors to identify the time traveller.

Yet, we’re well into the 21st century now and none of that flashy stuff is available yet. OK, so we’ve got a space station up there but we’ve not even set foot on Mars yet never mind taken flight to the stars. Robots are pretty boring pieces of equipment too and certainly don’t walk around like they did in the films.

Actually, we have quite a lot of the 23rd century technology knocking around: the mobile phone was a communicator in Star Trek, the talking computers appeared in the early 1980s and disappeared soon after, the memory chips that Mr Spock always seemed to be shuffling are our SD RAM cards. It’s just that we don’t have the really interesting stuff.

If you’ve not come across him before, have a read of the summary here or perhaps the analysis here.

One thing to note is that, whether or not he was a genuine time-traveller, it seemed to be impossible to prove one way or the other at the time. After all, you can’t really expect a real-life time traveller to know the result of the lottery next week, can you? Neither can you realistically expect them to have intimate knowledge of small events such as happen day to day but whilst you could expect them to know about significant events. However, aside from World War 3 breaking out next Tuesday you can’t really rely on what’s significant for us now to be equally significant for them in, say, 100 years and vice versa.

For example, if our time traveller were to go back to 1908 who would believe him when he said a civil servant would make the first theoretical breakthrough that proved that time travel was possible? And, yet, that’s exactly what Albert Einstein went on to do.

Likewise, whilst we consider 9/11 very significant, who can say if that will still be the case 100 years from now?

Even inconsistencies in the John Titor dialogues mean little. For example, say you went back to 1938. You could say that people still sat around the modern radio (ie TV) listening to it as people did in 1938 but equally you could also say that people didn’t listen to the radio much anymore. Seemingly inconsistent in 1938 terms but entirely consistent from our viewpoint in 2008.

Finally, there’s the problem that a time traveller could affect future events. What if you went back to 1999 and started talking about the events of 9/11? Would the events of 9/11 still happen? Certainly if the authorities believed the predictions, but perhaps also if those predictions were widely enough distributed and nobody fully believed them it might be enough to simply suspect that they could be true.

It turns out that the time from it being in science fiction and the genuine article being available in the shops is under 20 years. The computer tablet that Captain Kirk used in 1969 was available in the shops by 1991 and the communicators (ie mobile phones) were around even sooner than that as indeed were talking computers (which ironically were launched by the early 1980s and considered obselete less than 10 years later!).

In fact, aside from the warp drive (theoretically possible, if somewhat beyond our current capabilities) and the transporter (sadly, probably not possible), every single piece of technology on the original Star Trek series is available in the shops today in some form.

So, when you’re next watching some piece of science fiction set in the far distant future don’t be too surprised if you find all that technology that they used in the shops a decade or two later.

One of the features of Einstein’s theory of Special Relativity is that time is allowed for by the equations. So, although you might think that time travel is the work of science fiction it is scientifically possible.

That’s not to say that you will be able to nip out and buy a time machine anytime soon. At present, we’re pretty much in the equivalent time to that some decades before the Wright brothers took to the air. That’s to say, it’s a time when the only potentially possible technologies which would enable time travel involve black holes and naked singularities and various things that, at the moment, appear to lie well beyond our capabilities for the forseeable future.

However, the “forseeable future” can be very near-sighted sometimes. Already experiments are going on in CERN which deal with things closer and closer to naked singularities.

But surely all the paradoxes (killing your own grandfather before you were born etc.) mean that time travel is impossible? No, just as it was often “proved” that it would be impossible for a lump of a metal to fly through the air in the decades pre the Wright brothers, just because some armchair philosopher “proves” that it’s impossible doesn’t mean anything. The fact is that it IS allowed for within Einstein’s theory which, so far, has been proven at every juncture.

Ah, but, if time travel were possible then how come we aren’t knee deep in time travellers? Good question. Perhaps we are but they’re very good at concealing themselves or perhaps our era just isn’t very interesting. Or maybe it’s just something trivial like they just don’t have enough power to get back as far as us. None of those mean that time travel isn’t possible though.

However, if you think about it, chances are that if/when someone does build a time travel machine then it almost certainly would have limitations along those lines. More than likely the first experimental use will involve travel back/forward just a matter of seconds or minutes rather than centuries. My guess is that it will have limitations for quite a while as the technology is worked on. After all, the first plane didn’t go terribly far and the top speed of the first car was a fairly sedate 10 miles per hour.

Chances are too that, regardless of who develops the technology, that it will be grabbed by some government organisation because, let’s face it, time travel would be a pretty serious weapon in the hands of the “wrong people” (whichever way you define that).

Anyway, let’s suppose that we do have such a technology and that we can’t go back more than seven days (in the absence of any logical way of deciding what the real limit might be initially). Would it be any use?

Perhaps the best example of how you might use it would be to prevent 9/11. After all, that was an event that could have been stopped had the relevant information been available as little as a day ahead of time. Or could it? Were the planes used the only ones with terrorists onboard? How do we know that there weren’t more people who would have boarded other planes for a similar attack later the same day but couldn’t as everything was grounded? We could go on for ages with such assumptions, but let’s assume that those were the only planes that would ever have been involved.

Had the technology been available then, would it have been used? Your first reaction is probably “yes, of course”. Think about the implications if it had been used though. Yes, thousands of people would have been saved that day, but that single event changed a number of significant events afterwards. Wars were started based on the premise that they had to be to prevent further 9/11s, security in airports around the world was tightened up presumably preventing various attacks, more significantly perhaps the public attitude towards terrorism in America changed dramatically making it quite dangerous to be labelled a terrorist (hence the likes of the IRA downing tools for example).

In fact, what you’d really need would be the capability to analyse the full impact of removing 9/11 from history before you said “let’s erase that event”.

If you were a conspiracy theorist, you might wonder how come there don’t appear to be any events in the recent past where a Seven Days style time travel device could have been used (for that matter, how come the series was cancelled just as it seemed to be getting closer to reality). All we’ve had of late have been ongoing events that look rather difficult to resolve and certainly going back seven days wouldn’t fix any of them. Interesting, eh?

Anyway, forget about jumbo jet time travel capability and think more Wright brothers and you’ll get closer to what the very first time travel machine will be able to do.

Well, no, chances are that you are carrying around just such a tag right now. You probably call it a cell phone or mobile phone but it tracks your movements all the same.

They have to do that because of the way the technology used to implement the cells works. Essentially they need to know where every phone is so that they can pass phone calls aimed at it. A side-effect is that your mobile phone works as a reasonable accurate tracker of your movements whilst it is switched on. OK, not down to a few feet or anything like that but certainly the phone company knows which areas you pass through and if you’re in a car then it could almost certainly work out which roads you travelled along, roughly where you stopped, and so on.

And, yes, this information is available to the police. So even though you’re not a criminal they could still be tracking you.

Worrying, isn’t it?

Most people come up with the old favourites like stopping the First World War. OK, why not? Well, let’s say you’ve fully researched the history of the period and know which key event needs to be changed. Let’s ignore any complications and assume that the war wasn’t inevitable and that you would actually be able to change the relevant key event so that the war didn’t start.

So you’d do it, wouldn’t you? Well, roll time forward to the present and you’d find yourself in quite a different world. Some key changes that happened as a result of that war wouldn’t have happened. Business leaders would still be upper class, women wouldn’t be going out to work, chemical weapons would still be legitimate weapons of war, the tank might not have been invented yet (and therefore soldiers would remain “cannon fodder”)Â and we’d not have the United Nations because we’d not have formed its predecessor.

OK, we could do without those to save the lives lost needlessly. On the other hand, we’d still have the Kaiser in Germany. In that Germany wouldn’t have been beaten down, chances are that Hitler wouldn’t get to be Chancellor but would the Kaiser’s descendants be any better? I suspect that they wouldn’t, and could be a whole lot worse. After all, Germany would be going into the equivalent of our second World War but with their economy in reasonable shape and with another 10 to 20 years of time to play with.

So, in effect we could end up with somewhat more advanced technology being used to deliver not bombs but chemical weapon payloads. “We” would almost certainly lose that kind of war.

Would you still stop the First World War happening?

If not, what else would you change?