As humans we have gazed at the stars from our earliest times and wondered at what could possibly be out there. In the last century our journeys into space have progressed substantially with the Apollo missions and the construction of the International Space Station, humanity has taken its first step to the stars and in becoming a galactic species.
However modern technology faces great limitations to traverse the great interstellar distances. The nearest star, Proxima Centauri, is 4.3 light years away from our sun that means that travelling at the speed of light it would take about 4.3 years to get there. With the speed of today's spacecraft it could take 162,652 years an incredibly long time for a one way trip and by the time of arrival the star would have long moved away. So at present interstellar travel is highly impractical.
The speed of light is the speed limit of the universe and exceeding it is impossible according to Einstein’s theory of Special relativity but constructing spacecraft to travel at that speed may be impossible as well. Through his theory it suggests that as one approaches the speed of light their mass increases as well hence the energy needed to continue accelerating will increase as well. This could lead to an almost infinite amount of energy being required.
The possibilities of interstellar travel may seem hopeless but technology always finds a way of breaking barriers and theories are constantly proved wrong or a loophole is found. Einstein's theory leaves room for the existence of wormholes, a shortcut through space-time that could transport a body from one point to another instantaneously. If they exist and if they could be safely traversed this would be the greatest solution to mankind's problems with the limitations of normal travel.
In the immediate future technology is rapidly advancing to make travel more practical and at faster speeds. The Bussard ramjet is a proposed craft with a scoop at the front that would intake hydrogen and use it to propel at about 16% the speed of light which would certainly decrease travel times.Various other craft utilising new technologies such as solar sails could make space travel a reality.
Humans will no doubt one day reach the stars either through 50 year journeys or shortcuts through space-time. Will it happen anytime soon? Unlikely but the rate at which technology advances continues to increase daily and who knows maybe one day soon we could be the ones traversing the stars.