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• A comment on Conversation: Space 2050: Are we prepared for meeting 'Alien' life?

  Sep 5 2011: Hi Astra,
  
  I'm sorry, poor choice of words in the first instance. What I meant is that technologies that aim at maximising speed will limit deviations from any given bearing. Going faster essentially commits us to going in one direction.
  
  Of course, this direction will be carefully chosen, but at the expense of all others.
  
  As for the wormhole machine, it would require a mastery over the force of gravity. If we assume this mastery, there is nothing in current theory that precludes the possibility. So the question becomes 'is it in principle possible to harness gravitational forces without collapsing the surrounding spacetime?'. I don't know the answer to that one. But either way, we are seriously far from that degree of advancement.
  
  And as you say, it's all too easy to become bogged down in interpretation of temporal reference frames, but I think it's an aspect inherent to any discussion about space travel. Time and space are related. One cannot change one without affecting the other.

• A comment on Conversation: Space 2050: Are we prepared for meeting 'Alien' life?

  Sep 5 2011: Hi Stephen,
  All it means is that current theory allows for it, but this theory has not begun to translate into practice. At this point the only entities with enough mass to form a gravity well with walls more than 90 degrees are black holes. Unfortunately, their power requirements involve more than three times all the mass in our solar system, and in their natural state they will crush your body into subatomic particles at the speed of light.
  
  So, we have a long way to go before we can start talking about "possible" in any meaningful sense.
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  A comment on Conversation: Space 2050: Are we prepared for meeting 'Alien' life?

  Sep 4 2011: Dear Astra,
  
  I believe higher speed is almost certainly not the answer, especially when we would be forced to pick an arbitrary direction in which to travel. And even if we do manage to perfect local interstellar drives to a point where we could reach Proxima Centauri in as little as 6 to 10 years, relativistic effects would make it a one way trip for the explorers.
  
  Currently, the fastest human-made object - the Helios probe - travelling at 250,000 km/h, would take about 144 million years to reach the centre of the Milky Way. So, quite a wait! Ion and photon drive systems could knock some time off the figure, but they would take some years to get up to speed and are quite power hungry.
  
  I would much rather back your second research option. At this point, the ability to punch a hole through space-time is still 100% theoretical. We are nowhere near even harnessing the energies required to accomplish this.
  
  But consider this thought experiment: Fast forward a thousand years. Cold fusion powered ion drives allow us to travel at close to the speed of light, so we launch an unmanned probe to a star on the opposite edge of the Milky Way. But shortly thereafter, we make a breakthrough: a working, programmable Einstein-Rosen bridge device, which we use to travel to the same star instantaneously. By the time our unmanned ion drive probe reaches the star 84,000 years later, the descendants of the Einstein-Rosen bridge travellers are unlikely even to recognise it, and may well regard it as a primitive alien artifact!
  
  This illustrates which avenue deserves the research.
  
  In any event, a wormhole device would open the doors not only to distant corners of the universe, but also distant times past and future. In view of my earlier argument, this makes the probability of finding life much higher, because we could meet our little green men millions of years before their star burns out. This would not be possible with conventional space travel.
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  A comment on Conversation: Space 2050: Are we prepared for meeting 'Alien' life?

  Sep 1 2011: Dear Astra,
  
  Don't get me wrong. Our presence here is in itself proof that the universe can nurture life. But the birth and development of self-replicating molecules and eventually complex organisms is measured in astronomical time - that is, in billions of years - even on an ideal planet such as ours.
  
  Under ideal conditions, life could take 1.5-2.5 billion years to develop, as it did here. The universe itself is less than ten times older than that. When dealing with such vast time scales - and adding to this environmental factors that may stand in the way of evolutionary processes - we have to consider the possibility that the window of opportunity for sentient life may be rather small. Either way, it is limited to the lifetime of any given star. In another billion years, our own sun will be too hot for water to exist in liquid form. Once a star burns through its main sequence and balloons into a red giant, it's game over for life in its solar system.
  
  Of course it is possible for life to have developed elsewhere. But there is no telling how long that would take. We have no way of telling whether Earth was simply an early developer. In addition to the odds of finding life elsewhere, there are also the odds of finding it at a specific time. Our little green men's star may have burnt out millennia ago - or still be coalescing from gas. We simply don't know.
  
  Seen from this perspective, I believe that we should follow an Ockham's Razor approach. In the absence of evidence to the contrary, we should proceed from the assumption that we are alone. The vast responsibility this entails is that we are the first best hope: the keepers of life in the universe. It may indeed be up to us, and us alone, to seed and populate the Milky Way and eventually other galaxies.
  
  We as a species cannot do this while bickering amongst ourselves, warring or otherwise showing a general disregard for how precious life is.
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  A comment on Conversation: Space 2050: Are we prepared for meeting 'Alien' life?

  Aug 31 2011: In the absence of evidence to the contrary, I like to approach it from the other side. The pervasiveness of life on earth is such that it is easy for us to assume life must exist elsewhere. But life on earth, for all its diversity, started with a single proto-cell. Which may have been a fluke.
  
  The odds against life - and especially sentient life - are literally astronomical. So, I would like to answer your question with another question:
  
  What if we find nothing?
  
  What if ours is the only (or at least the first) world where an insignificant little flame of life is kindled? What a vast responsibility that thought should instill in us!