Mars's Ancient-Civilization Hypothesis: Brandenburg's Nuclear-War Claim and the Isotopic Debate

To the point

Mars once hosted an advanced civilization that was wiped out by a nuclear war, a claim made by John Brandenburg based on xenon-129 and other isotopic signals, but it remains controversial because there is no crater evidence or radioactive fallout proof and NASA data are inconclusive, with supporters like Jason Reza Jorjani and references to a declassified CIA project, and the timeframe is debated from about 200,000 to 100 million years ago.