Another way aliens could discover evidence of human activity is through the artifacts we’ve sent into space. The Voyager and Pioneer probes are equipped with messages for any beings who might encounter them long after they leave the Solar System. Although the chances are slim that they’d be found in the vast emptiness of space, it’s still possible. Some intelligent, space-exploring aliens could someday find these artifacts and learn about Earth, its creatures, and human cultures.
The Lucy spacecraft is a different kind of artifact. Right now, Lucy is on its way to study the Jupiter trojans, groups of asteroids that share Jupiter’s orbit around the Sun. After it completes its study of its targets, Lucy will continue to orbit the Sun for millions of years. It carries a sort of time capsule from Earth just in case it’s someday discovered by an alien species that comes to our Solar System in search of us, only to find that humans have long since gone extinct.
This possibility may sound bleak, but it’s another avenue for something deeply meaningful. Somehow, someday, our species and its capabilities might come to be known by others who share our most fundamental characteristic: life.