by londons_explore 12 hours ago
It is quite remarkable that the question of life on mars (or not) hasn't been answered conclusively despite a lot of human effort to get an answer.
NASA intentionally completely gave up on trying to answer the Mars life question for multiple decades and only very recently has come back around to the idea of doing life finding missions.
there probably never was any there for a meaningful amount of time, but it's incredibly hard to prove a negative.