[JurijD]

I don´t think we´re hundreds of years from having self-sustaining colonies on other planets. All the technology that we´d possibly need has long since been invented (say 30 years ago). If they could send a man to the moon in 69 we can most surely send several to mars and have them stay there indefinately... the ony problem is the will to do so. (if you have the will you find the money and the means)

We have the technology to construct self sustainable environments... there are about 200 of them floating uder the worlds oceans (called nuclear submarines) They surface once every 6 months only to resupply on food beause it would be too unpractical to have it produced on-board. Everything else... water, oxygen, heat etc. is produced by the nuclear reactors that turn CO2 to O2 and recycle urine and the vapour in the air to usable water.... In a hypothatical colony we´d only need to bring plants along to produce carbohydrates for us to eat (I admit, it would be a strange diet but one would be able to live off it indefinately) And if we could genetically change certain cells not to grow into animals but just to produce large quantities of proteins we´d have ourselves a meat substitute... we´re not there yet but its completely possible.

sailing off to distant stars is another matter... We simply don´t have the technology to do so in the desired time span (10 years there and back).

One proposal is to use say ion engines to propel enormous ships that carry hundrets of thousands of people in a self-sustaining enovironment with an fusion energy source that would Last for centuries to the nearest stars... they would require 50 years to get there and they would never return... but their offspring would construct a new civilisation on a planet orbiting that distant star and build new ships and send them off to yet other stars.... it has been calculated that it would take several million years but in the end we could colonize the enire galaxy using this principle...

Well I´m still hopefull that physics will save us and discover that travel over and beyond the speed of light is indeed possible... and I´m a firm believer in the saying that anyting is possible.