Renowned astrophysicist Stephen Hawking once remarked that humankind would need to colonise space within the next century if it was to survive as a species.
"It will be difficult enough to avoid disaster in the next 100 years, let alone the next thousand or million," he said somewhat pessimistically last year. "Our only chance of long-term survival is not to remain inward-looking on planet Earth, but to spread out into space."
The prospect of long-term space travel has led scientists to consider, increasingly seriously, the following conundrum: if travelling to a new home might take thousands of years, would humans be able to successfully procreate along the way? The early indications from Nasa are not encouraging. Space, it seems, is simply not a good place to have sex.
This pessimistic outlook would change if humans were able to create an effective "force field" or "energy shield," that would protect a starship's human occupants from interaction with cosmic rays and any other energetic particles in interstellar space. Such a hypothetical energy shield would also be required to physically protect a starship from the enormous friction that would be generated by the ship moving through the interstellar medium at speeds close to the speed of light. To read the rest of the article, click here.