Life on Earth is a newcomer in comparison to the age of the Universe. The first signs of life on our planet appeared around 3.5 billion years ago, but the Universe has been around more than 10 billion years longer. If life is not unique to Earth, it is extremely feasible that something came before us and would be much more advanced, assuming these aliens followed the same trajectory as life on Earth. And judging by humanity's past, a more technologically advanced species often has no regard for civilisations not as advanced on the technological timescale, such as when Europeans encountered native Americans, and almost killed them off in order to conquer the New World.