Are their aliens out there?

One common thread with most Sci-Fi films and television shows is that the universe is full of alien life (and they all speak English), so just how realistic is this? There is an unimaginably huge number of planets in our galaxy, and there are billions of galaxies in the Universe. The probability that there is life on other planets must be high, although the probability of them speaking English has got to be pretty low :-)

Seriously, the question should not be whether there is life on other planets, but whether there is intelligent life on other planets. I believe if the conditions are right, then life will spontaneously appear. That life will continue to evolve and develop in complexity over time until life matches the needs of the environment. For example dinosaurs were the dominant species on Earth for millions of years, compared with hardly any time at all for humans. However, they never evolved any significant levels of intelligence. They didn't need to. Man learnt to walk upright, freeing his hands to use tools. He had the need to think, to plan, to develop strategies for survival. Man evolved and became intelligent.

Now don't get confused between intelligence and technology; a cave man, a Roman soldier and a "modern" man are all just as intelligent (although there is an argument that man is dumber now - the reason is that you had to be clever to survive long enough to breed, whereas nowadays it's much easier to live long enough to have children no matter how dumb you are). The difference between why it appears we are more intelligent than a Roman soldier is time - the time needed to develop technology, to record progress for future generations and the desire to discover. We are older as a civilisation and we learn the lessons from our forefathers.

What about aliens? The same applies. If the conditions are right on a planet then I believe life will emerge. Whether the life will become intelligent will depend on the environment and the needs of the life form. How intelligent they become will depend on the time they have - just imagine a civilisation that was technologically as advanced as we are now, but a million years ago. We could not even begin to imagined what they could be like now (I believe that at that level of technology their biological processes will be blended with technological innovations, so that the two are merged together, but that is just my opinion). Their technology would appear like magic to us, just as ours would to a Roman soldier.

Civilisations have a life span, some could swing between technological brilliance and the stone age. The reasons could be natural disasters (the probability of a large meteor hitting the Earth is small but over 1,000,000 years the chances don't look so good), wars, diseases, or even self destruction. Even so, the universe is sufficiently large that we believe there are alien worlds out there right now which have a wide range of technological abilities, from planets where the highest form of life is bacteria to planets with such advanced technology we could not even begin to imagine.

Assuming there are civilisations out there sufficiently technologically advanced to travel here (no mean feat), and they know we are here (the galaxy is a big place and we are a very small planet), then it is possible they could have visited Earth. I do not think it is at all likely for the following reasons:

• Even with our current level of technology we are watching the sky very closely. Indeed, we have just photographed planets from Earth (nothing the size of Earth yet, but in time). We could soon be approaching the stage where we will be able to see evidence of extraterrestrial activity - so far we're seen nothing in our neighbourhood. Don't forget though, when looking out into space we're also looking back into time !

• It's our opinion that if an alien race did come here then they would let themselves be known. I have heard arguments, mainly drawn from Sci-Fi, that they would merely watch and observe us, but I don't think so. I think it will be a global event, if it ever happened.

In The Day the Earth stood Still an alien visited Earth with technology so far in advance of ours that we didn't have a clue how it even worked. The same could probably be said for War of the Worlds. In both cases, the arrival of the aliens turned into death and destruction. In comparison, UFO watchers state that UFO spacecraft have been watching us for years. I think that the reality is probably somewhere in between. As I said above, I don't believe aliens have been here but if they did why would they bother attacking us? I've seen Sci-Fi where aliens come here for water but that's nonsense, there's plenty of water in the universe. The same argument applies for minerals and other resources. We do have something that I believe is very rare that they could be interested in, we have bio-mass - in other words, food. They can eat us!

We don't know for sure, but if life is rare and if they go to all the effort of coming here, it must be for an end purpose. My view is that their arrival would be very obvious and we will quickly know their intentions, one way or another.

What makes the best Sci-Fi aliens? This is very much a personal opinion. We believe that any alien that looks remotely human is not that convincing. We think that if you really want a good alien baddie it's got to look alien. In my opinion there are two that are particularly good: the Daleks from Dr Who and the Replicators from Stargate. The reason is that they have incredibly highly advanced technology and they want to use that technology to destroy all life apart from their own. Think about it, you can't reason with them - they just want you dead. Of the two we think the Daleks are better (I went off the replicators when they took human form!)

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