If you’ve always been fascinated with Space and Physics, you’ll have asked the question at some point… ‘Is time travel actually possible?’ Well if you have studied Einstein’s theory of General Relativity, you’d have to agree with Professor Brian Cox that at least in theory, it’s feasible.
It seems that if we wanted to go back and meet our forefathers then this is a total non-starter… General relativity doesn’t allow mass (that’s anything with atoms) to travel back in time, but it is, in theory, possible to travel forward and meet your great grandchildren if you can gather enough momentum relative to a point in space.
To do this we would have to travel fast… very fast! In fact, in order to get a suitable differential in speed relative to a starting point, you would have to be travelling at a substantial portion of the speed of light for several years, which currently is both infeasible and very dangerous.
How To Time Travel
So let’s conduct a thought experiment. We’re going to think what we need in order to travel into the future… In order to do this we’re going to have to move into Space, because landlocked on Planet Earth we’ll never be able to get up to the speeds necessary to move forward in time. So we build a space ship, powered by a REALLY powerful engine, one that can keep us accelerating until we reach, say, 95% of the speed of light.
If we were able to do this and kept up this speed for several years (not a problem because there isn’t anything to slow us down in space) then yes, if we returned to our starting point on Earth we would find that we’d aged a lot less than people stuck on the Planet. This, in relative terms, is time travel!
Exploding the Dream
That’s great then… we know, theoretically, that it may be actually possible to travel forward in time. Unfortunately there are a few other little practicalities we have to take care of before this theory becomes reality.
Ask any school child about Einstein and they’ll probably reel off E=MC². This famous equation describes how Mass and Energy are related. This little equation is the cornerstone of modern Physics and means that we can quantify how much energy can be harnessed through nuclear reactors and has allowed the progression of many other modern things we take for granted.
But E=MC² also tells us that as we move faster, we get heavier. A lot heavier! Gaining enough speed to take us near the speed of light means that we’re increasing our own mass by a factor of two and also squashing ourselves so that our bodies are half the size they were before. This would constitute an almost certainly terminal assault on our bodies! We would, in fact have to shield ourselves from the effects of mass gain and the relativistic effects of contraction associated with it, which isn’t going to be easy…
Cosmic Rays and Other Dangers
We look up into Space and imagine a cold, still expanse, full of wonder. The reality, in fact is far from this. We survive on Earth thanks to a protective barrier of magnetism and atmosphere, generated by the spinning core of the Earth and by billions of years of geological forces.
The constantly generated magnetic fields which circle the Earth protect us from high energy particles, high energy x-rays and micro meteorites which inhabit Space in all directions. For anyone who has seen the recent movie Gravity this will be very familiar.
In fact Space is a very, very dangerous place to inhabit for Humans without a complex range of protective devices, so our theoretical Time Travelling space ship would need some industrial strength protection against cosmic rays, micro meteorites, gamma radiation and of course bigger objects which float round in Space like Comets, meteors and dust. This is before we start to think how we’re going to build a ship which would be able to take the strain of relativistic speeds on the hull!
Shielding Against Disaster
You can see that to protect our time traveler in our theoretical space ship, he’s going to need some pretty special ‘Sci Fi’ like force fields to protect his body. What we really need is something which will repel any high energy objects from hitting the ship and which will counteract the effects of relativistic effects on the body… It turns out that creating a force field is not only possible, but has been in active development since 2012, so it may be that in the future a ‘Star Trek’ type force field could be created.
Getting to Speed
In order to get up to speed as mentioned previously, we’re going to need a very serious engine. Chemical rockets as used in the Apollo missions and nearly every spacecraft since are non-starters because the amount (and mass) of fuel needed is prohibitive for a mission of this type, so what are the alternatives? Well nuclear engines will, in theory, get us enough sustained thrust over a long enough amount of time to approach a small portion of the speed of light, but nuclear fission is only around 3% efficient and gives off a large amount of very nasty Gamma and x-ray radiation.
All that radiation wouldn’t be a problem as we would use our force fields to protect us, however, what we really need is an engine which has efficiency approaching 100%, that way we can carry less fuel and less mass. To achieve this, we need to again turn to ‘Sci Fi’… Any fans of ‘Star Trek’ will know that the USS Enterprise runs on Antimatter. This elusive, hard to create material is basically a mirror of normal matter and is very real, in fact Antimatter has been produced in several nuclear accelerators around the Planet.
The wonderful (and terrifying) thing about Antimatter is that when it comes into contact with regular matter, annihilation occurs where all of the mass turns into energy. This sounds great, but is it actually possible to create an antimatter engine? Well it seems that yes indeed, even here we’re on the road to making this a reality, with plans afoot by NASA to build a working Antimatter engine which will power future missions to Mars and other planets. This extreme efficiency engine should be able to give us a substantial portion of the speed of light we need to become time travelers.
Building The Dream
So is anyone ever going to build this theoretical time travel space ship? Possibly, but not for the purposes of time travel. It’s a fact that as we move towards proper interplanetary space travel we are eventually going to have to deal with relativistic time shift effects, but that will be a consequence, not a goal. While the rest of us check our wrists and wait patiently for the time when we can travel into the future, the fact is the technologies required to enable us to move forward in time are probably hundreds of years into the future, so I, for one, am not going to hold my breath!
David Fairhurst is an SEO professional and technology enthusiast who can’t wait to travle through time!