Is Time travel possible?

Building your first time machine..

Time travel has featured regularly in science fiction, but is it really possible?

Many say that time travel is indeed impossible. Albert Einstein even stated that, although he believed that time travel into the past may be impossible, travelling into the future would not be. This may sound strange, yet it has already been proven by Einstein himself.

1. Two identical twin brothers are born together, and grow to become rocket scientists, and build a very fast spacecraft.
2. Once completed, brother #1 decides he should pilot the craft on a very fast, distant round trip through the cosmos.
3. Brother #2 stays on Earth, and happily waves him farewell, as he watches the rocket blast into outer space.
4. Brother #1 travels very fast, very far, in his new spaceship. For him, the time on his watch ticks steadily by for several years. After five years, he decides to turn round and head back to Earth.
5. When brother #1 arrives back on Earth ten years after he first left, he finds all sorts of new innovations and fashion shocks. For although he has only been away for a short time, for planet Earth, it has been longer - this is because "time is relative to the observer". Time is relative !
6. When brother #2 arrives to welcome him home, they are both in for a shock, as brother #1 now appears to have aged only ten years, whereas his brother appears to have aged much faster - they are no longer identical !

This may sound like madness, yet it has been proven both mathematically, and in practice - using a couple of synchronised atomic clocks and a very fast jet aircraft.

What does this mean?

Well it means that you may be able to travel into the future by travelling very fast. That by doing so, you are travelling into the future, with reference to all other observers watching you. For you, time passing is no faster than normal. Yet this round trip back to Earth should take you well into the future, depending on your speed, and distance travelled.

There is a much easier way to do this however?

Simply freeze yourself in time, and thus, as the observer, watch the world pass you by. Suspended in time, you may age very little, or very slowly, compared to the outside world. This has also been tried, but not tested thoroughly. Cryogenic suspension has placed many in deep freeze, hoping for a bright future, and a new start. The down side to this however, is that no one as yet has been revived from this frozen state, and many believe it is impossible to do so.

So what about travelling into the past, is this possible?

This is where things get more difficult. On first inspection, you may first come to the conclusions that travelling into the past would involve the reverse actions to travelling into the future as explained above. That, to travel into the past, you would attempt the complete opposite to going very far, very fast, by going very slowly. But this is not the case, and this will certainly not take you back in time.

This is because, despite your actions, the time line is still going in the same direction - we may call this the forward direction of time. By going very slowly, you merely get nowhere at all, even by going more slowly that the slowest thing ever, coming to a complete stop, and attempting to go even more slowly; you are prevented from time travel because of this time line.

Some believe that it may be possible mathematically, to go back in time, primarily because equations permit negative values, or permit values to be reversed to produce a complete reversal of polarity - yet this still does not help us in our physical world when it comes to our time line. For us, it would appear that we cannot reverse this time line in the dimension that we all exist.

This is an over simplified explanation of the problem, as both the writer and this short piece are neither qualified nor clever enough to give you the full picture. Yet, this is the basic outline of the problem at hand. The popular physicist Stephen Hawking has also claimed that it would be impossible to travel back in time, and he proposes a very interesting slant on the case; he states that if someone in the future had already constructed a time machine to travel back, then we should be able to bear witness to this now, and actually meet these visitors from our future?

Yet would we really know if they actually do, or have visited us from the future?

If they were smart, then really, any visitor from the future would not advertise the fact, and do their very best to conceal precisely this?

There is also another case that disputes the possibility of travelling back in time, or at least limits the possibilities of such a machine.

1. Man invents a time machine to travel into the future and into the past.
2. He freely jumps aboard, and travels into the future and back again to his house and time.
3. He attempts to go farther back into time, but is prevented, why?

Many say, it would be impossible for the machine to do this, because, it may only be permitted to travel back to the time of it’s first construction. If the machine could travel farther back in time, then there would be no case, or possibility, for the machine to be built at a later time, (in the future), as it would already exist, and therefore cannot be invented at all, (or re-invented).

Yet this is rather like one of those paradoxes that we commonly hear about time travel; for example, the one where the guy goes back and shoots his grandfather, and then disappears in a flash of light, and leaves us with the problem of how he was born to go back in time in the first place?

The answer to this paradox may be, wait for it... parallel time lines and multiple Universes. In other words, if travelling back in time is possible, then by changing even the slightest thing, (like shooting your grandpa), you would create an alternative time line, which must entail creating a completely parallel Universe to the one you originally came from?

This sounds like nonsense, but is, in fact, the only reasonable way you could possibly travel back in time and resolve any change, or problem you may encounter. Experiments in quantum mechanics and physics imply, that on an atomic, and sub-atomic level, particles may actually be doing exactly this - splitting our Universe. That every time a quantum decision is made at a sub-atomic level, another Universe may be created?

Again this is too deep and complex for this short piece to accommodate here, but a quick search on the web will usually find a more complex and detailed presentation for this argument.

So, to surmise, we cannot go back in time - correct?
... The answer is, we still may be able to do this !

---

Wormholes..

According to the experts and the big equations, (out there!), it is possible that such a thing as a wormhole may exist. This may provide a short cut through time and space, and would permit travel back in time, as well as into the future.

What is a wormhole?

Well imagine the Universe as a very large balloon. I know it’s difficult, but you can do it if you try. Analogies are cute, and can be misleading, but this is a popular one, so we can be somewhat comfortable with it at this stage.

The reason for this analogy, is that space-time, (space and time combined as a single phenomenon), can be affected by gravity. Or more to the point, any thing that resides in our Universe, in our dimension, should be affected by gravitational attraction - including, and not exclusive to: stars, planets, galaxies, gases, particles, and even light. All these can be affected by gravity, and travelling objects, (matter), can be attracted, and trajectories "bent" by gravitational pull from stars and planets.

So far so good. You may be quizzing here why we should use the balloon analogy?

Two reasons really:

1. Because the Universe may be a closed model, as Einstein originally proposed - that if you keep going long enough, you may end up back where you started? Rather like travelling on the outside of an expanding balloon.

2. That the balloon analogy fits this explanation nicely to explain extreme gravity.

If you imagine the balloon as the Universe ever expanding, the surface of the balloon expands, and stars and galaxies move away from each other in all directions. You may travel on the outside of the balloon. Any heavy objects, such as stars, galaxies, and even "black holes", have large gravity that will affect you travelling past in a straight line, rather like a heavy object that bends and depresses the surface of our balloon; the depression draws you in, like gravitational pull.

Now if we take this idea to the extreme. How about gravitational pull that is so heavy, that it actually depresses the surface of our balloon Universe so much, that the surface sinks through to the other side. And yet still further, it actually punctures the outside of the balloon on the other side? Now you have a short cut from one side of the balloon Universe to the other!

This sounds extreme, and it is. Yet this idea is apparently mathematically possible. That it may be possible for wormholes like these to exist - but only on a very brief, and particle size level. That is, that particles may possess the ability to do this?

If this is the case, and the theory is sound, then this may be the first step to constructing a very large, very heavy machine that could puncture the space-time continuum in exactly this manner. A machine that could produce a wormhole long enough, and large enough, for a spacecraft to travel through, and take a short cut from one place to another?

How does this help us with time travel?

Well, if you imagine you have already overcome the physical impossibilities and constructed such a machine. Then all you really need to do next, is to calculate exactly where, say, the Earth was in space-time exactly ten years ago, and then puncture the space-time continuum to produce a wormhole that can provide a short cut to exactly this place. Et voila! you have just travelled back in time ten years to where Earth was, and still should be - you have travelled back in time!

Easy or wot?

Yet all this does raise another very important question,
....why would anyone want to travel back in time in the first place?

For more about wormholes see here...

Introduction to Wormholes

Back to contents..