What if we left the solar system?

Nothing that human hands ever touched has gone as far as Voyager I.

As of August 2010, Voyager 1 was at a distance of 17.1 Billion Kilometers (114.3 AU) from the sun and Voyager 2 at a distance of 13.9 Billion kilometers (92.9 AU).

A few new space missions out there are brewing. These missions involve a solar sail technology. Such ideas date back to Konstantin Eduardovich Tsiolkovsky! A Russian scientist (1857 – 1935). (Google him and you'll see his amazing progressive thoughts of that era, it's mind-boggling!)
But anyways, since Einstein's E=mc^2, it's a fact that photons carry a bit of momentum with them and therefore this momentum could be harbored and used in spacecraft propulsion! Currently, the idea of a 15 Astronomical Units/year speed is entertained to achieve a feat of getting hundreds of AUs away from solar system to explore. Thomas Zurbuchen of University of Michigan at Ann Arbor and Ralph McNutt of the John Hopkins University Applied Physics Laboratory are working on Large and Medium sized Solar sail crafts (36 ton and 1 ton respectively). Or another 500 kg spacecraft with a solar sail of 200 meters across will swoop towards the Sun to get flung out into space by the intense sunlight. Just before passing Jupiter's orbit, it would cast off the sail and continue on gliding outward. But at first the solar sails would have to get realworld testing done and be able to fold, since it'd be impossible to get those sails out in space unfolded.