A light year is a unit of distance it is the distance that light travels in one year for example the distance from the north star to Earth is about 434 light-years because it takes light about 434 years to travel from the north star to Earth the table is five stars in the constellation Cassiopeia and their approximate distances in light years from Earth light travels at the speed of 3 * 10 ^ 8 meters per second highlight each star in the table that is 7 * 10 ^ 17 meters and 3 * 10 ^ meters from Earth click the name of the start of highlight it.​