December 5, 2013
Interstellar travel will depend on the development of new physics. Rocket-based technology will never do it. Voyager 1 will take 25000 years to pass out of the oort cloud, let alone arrive at another system! There is a finite possibility of subatomic particles being anywhere in the universe, but this will have to be translated to a macroscopic scale, in a fully controllable way. This is still probably centuries away! Therefore any discussion of visiting other systems is purely academic at present.
An asteroid or comet headed for Earth is the only large-scale natural disaster we can prevent. Working together to fund our Shoemaker NEO Grants for astronomers, we can help save the world.