A light year is a unit of length that equals to just under 10 trillion kilometers. This is the distance that light travels in a vacuum in one Julian year. For more information, go to http://en.wikipedia.org/wiki/Light-year.
One light year is 6213711922373.34 miles. Top recorded manned space flight to date is approximately 25,000 mph. At that speed it would take APPROXIMATELY 28,000 of our years to travel one light year distance. Hence the need for suspended animation or hibernation on deep space journeys. Or a ship capable of faster than light travel like warp or hyper drive. Or a handy worm hole