John Brandenburg’s proposal that a civilisation on Mars was destroyed by nuclear detonations in the deep past, argued from the isotopic composition of the Martian atmosphere.
The argument
The Martian atmosphere carries an excess of Xenon-129 relative to the other xenon isotopes, and Brandenburg reads that ratio as the fission-product signature of two airburst detonations, which he locates over Cydonia and Utopia Planitia. He set the case out in conference papers from 2011 and in Death on Mars (2015), and connects it to the alleged artificial features at Cydonia.
Where it stands
Planetary science attributes the xenon ratio to the planet’s atmospheric history: early outgassing and preferential loss of the lighter isotopes to space over billions of years, a process that is modelled and that also accounts for the argon and nitrogen ratios. Detonations of the scale required would leave craters, melt glass and a distributed fallout layer, none of which has been found by any of the orbiters or rovers. The Cydonia features were resolved as ordinary landforms by Mars Global Surveyor in 1998. The site’s Mars xenon bench prices the isotope claim directly.
Connections
John Brandenburg · Cydonia · Closer Encounters · Jason Reza Jorjani · Jorjani - Danny Jones Podcast 2025 · Mars Cydonia RV 1984 · Hollow Moon Hypothesis · Ancient Astronaut Hypothesis