The human race is unlikely to ever reach the stars. The technical challenges are too great, the political will too weak, and the economic need too small to contemplate such a venture. Reaching for the stars is for romantic not realists.
First take a hard look at the technology. The stars are too far away for journeys to be practical. At the speed of light, the journey to our nearest star, Alpha Centuri, would take 4.3 years. Based upon current conceivable technologies a spacecraft could only travel at a modest proportion of this speed. The timescales would require journeys in excess of a human lifetime. The journeys would need to either support family groups, coping with ethics of birth, marriage and death in space or provide some form of hibernation for the duration of the voyage.
Now take some blue sky research. Physicists think that it might be possible to travel faster than the speed of light by crashing through the fabric of space and time using a wormhole. A wormhole is a totally theoretical idea which would require an enormous energy field. There is no appreciation of whether a biological system, such as a human, could pass through intact. Nobody has considered the navigation and control aspects. Where would the wormhole lead and how could we communicate to someone on the other side of a wormhole? The idea is totally impractical.
The great problem with space travel is that it involves the transport of matter. This is a very inefficient way of moving over large distances in time and space. It will be seen to future physicists as the stone age does to us. Matter, not information is trapped by the constraint that nothing can travel faster than the speed of light. Scientists have already demonstrated quantum entanglement. This is a weird phenomenon in which two particles appear to interact instantaneously. Scale up would be hideously difficult but there is a possibility that we could communicate instantaneously over long distances. Why would mankind need to transmit matter?
An expedition to the stars would require considerable investment and political will.
Looking at history, voyages of discovery were often funded as commercial ventures, or occasionally on the whim of a great man. The Apollo missions were an exception driven by the Cold War and the military significance of large rockets. It is difficult to see how an extremely costly space mission could be justified in a democracy. The NASA manned mission to Mars is already controversial. The capital required is far beyond the scope of private enterprise. Moreover, there is little need to put man into space, exploration can be conducted far more cheaply and effectively using robotics. These do not need the expensive life support systems that are needed to support the fragile human body.
Economically, the investment in a mission to reach the stars would be enormous. Mankind will not turn to the stars for resources, but might consider a venture to relieve an overcrowded Earth, as an insurance policy, or for vanity.
The history of science shows a progressive movement away from a homocentric viewpoint. The Sun is not that special, nor is our planet. There ought to be innumerable civilisations like our own yet there is no evidence that any have reached for the stars. The task is too great.
Mankind has a love affair with the stars. It is interesting to see the blind optimism among those who believe in journeys to the stars. Their arguments do not include the fine details that turn theory into reality.
