Voyagers

Voyager I and II are the two space-crafts launched by NASA to extend the exploration of beyond the neighborhood planets to the outer limits of Solar system. The twins space-crafts are the only human made objects that have left Solar system breaking the gravitation field of Sun to wander into the Interstellar space for next 20000 years. The space-crafts will lose contact with us in a few years as their radio transmission long dead, they will roam alone in cold cosmic dark far from home for billions of years. So, what's the point of travelling for billions years without contact? The answer is the Golden Record.
Both the twin consists of a golden record, a disk containing greetings in 59 human languages and one whale language, 116 images on our science, civilization, ourselves and 90 minutes of earth's greatest hits and sounds of waves and winds selected by Carl Sagan. Voyagers are traveling with memories just like its name. We do not know there is any other intelligent life in the universe but at least there is some chances. So in hope of being found by those species and let them know of us and our home, voyagers will roam for eternity; a greeting to the aliens from our home.
But in billion years, our earth may not be in existence. So, think about this way;
"The voyagers will be travelling bearing the memories of a world that is no more".
Or
We might get extinct as our home planet might be hit by similar kind of asteroid that made the extinction of the dinosaurs and life will emerge from basic level. And if someday it evolves to the intelligent level, it will venture to the outer earth and later to the outer solar system, and there they will find a lonely strange object carrying our memories. They will know about the Earth, about us, about our culture, how we lived, what we achieved, how are we similar or dissimilar to them and they will forever thank us even if we won't exist.