Leaving Planet Earth

Planet Earth is now approximately 4.5 billion years old. It was formed as part of our Solar System consisting of the Sun and 9 planets (some say only 8 planets, as Pluto was demoted). As our planet needs the Sun which supplies all it’s energy in one form or another, when the Sun begins to die, then it’s curtains for Earth. Of course this is not expected to happen for at least another 4.5 billion years. So why worry?

Well, no need to at the moment, but with man’s hunger for exploration (and I really believe that this hunger is one of the driving forces behind the animal called Homo Sapiens and if it couldn’t be satisfied we would atrophy) we will explore the Solar System and beyond. Then we will colonise and live on new planets orbiting strange new stars (of course it is to be hoped that we will have been able to bring our intelligent and emotional aspects into line so we won’t butcher other peoples or races in order to do this).

But the real interesting question is how are we going to get there? Distances in space are so vast they are practically incomprehensible. Four and a half light years to our nearest star Alpha Centauri. That means it takes light four and a half years to reach us from that star, our nearest stellar neighbour. Light travels at approximately 186,000 miles per second. That places Alpha Centauri about 26 million million miles away. That number is simply not graspable to the human mind; it’s just enormous. But travelling at the speed of our Voyager spacecraft (38,000 miles/hour) it would take about 80,000 years to get there. Even if we were able to build spacecraft which could go faster than this it would take many human lifetimes to reach our nearest star. And once we got there, it is almost certain that we would find no suitable planets for us to colonise. In fact we would have to go much further into space to find suitable habitats.

So conventional spacecraft don’t seem to be a viable option. What else then? What about a matter/antimatter engine? Antimatter is in very short supply and it’s not easy to make (besides it costs about $25 billion per gram). It is mainly used in big physics experiments using machines which collide particles at nearly the speed of light in order to study them. The property of antimatter which interests us is the fact that if you collide a particle of matter with a similar particle of antimatter they convert their total mass into energy with close to 100% efficiency. Such a matter/antimatter engine could bring us to more than 90% of the speed of light which is a considerable improvement. It means we could probably arrive at the Alpha Centauri star system (three stars, in fact) in less than 5 years. But we don’t want to go there! We need to find a solar system with an earth like planet. Current estimates say such a system may be as close as 20 light years away. So that means a trip of about 22 years. That’s a long time travelling in space in close proximity with your travelling companions. Would the human psyche be up to such a journey?

So we need something faster and now we go into the realms of Star Trek. What about a warp engine? Now that would be some invention, but in theory possible. As Einstein’s relativity theory says nothing can travel faster than the speed of light, then there is no way a spacecraft made of matter can break the light barrier. So we have to somehow reduce the distances. Warping space is one way to do this. Don’t ask me how this can be done as nobody knows (even if it’s actually possible), but let’s assume for a moment that it is feasible. In fact if it’s not possible, it doesn’t hold out much hope for interstellar exploration in the short term. We’re just going to have to go the long way round: hibernation techniques, or building huge craft capable of carrying thousands of people and taking many human generations to reach the stars. But let’s not get into that now.

According to general relativity (Einstein’s gravity theory) two points incredibly far away in real space can be brought very close together by warping the space between them. Actually by warping the spacetime between them, but let’s not complicate matters. If we can warp the space by creating what is termed a wormhole between the two distant points, we can travel practically instantly between them. Such technology, while nowhere within our grasp today, may not be so far off. I would estimate less than a thousand years. Which is quite annoying really, as I expect to be long dead by then. Ah well, you can’t have it every which way.