John Brandenburg, a plasma physicist at Orbital Technologies in Madison, Wisc. believes the Martian race was wiped out by nuclear explosion. In 2011, Brandenburg introduced the theory that the red color on Mars is due to a naturally occurring thermonuclear explosion, according to Daily Mail.

"The Martian surface is covered with a thin layer of radioactive substances including uranium, thorium and radioactive potassium - and this pattern radiates from a hot spot on Mars," Brandenburg previously said. "A nuclear explosion could have sent debris all around the planet."

However, the scientist with a PhD in Theoretical Plasma Physics from the University of California at Davis now believes ancient Martians - known as Cydonians and Utopians - were victims of genocide.

"Given the large amount of nuclear isotopes in Mars atmosphere resembling those from hydrogen bomb tests on Earth, Mars may present an example of civilization wiped out by a nuclear attack from space," Brandenburg wrote in a paper he shared with Vice.

"It is possible the Fermi Paradox means that our interstellar neighborhood contains forces hostile to young, noisy, civilizations such as ourselves," the paper continued. "Such hostile forces could range from things as alien as AI (Artificial Intelligence) 'with a grudge' against flesh and blood, as in the movie Terminator, all the way to things as sadly familiar to us as a mindless humanoid bureaucrat like Governor Tarkin in Star Wars, eager to destroy planet Alderann as an example to other worlds."

A video posted by a French YouTube channel depicts the "cloud of smoke" on Valles Marineris, a 2,500-mile (4,000km) long canyon on Mars. "The image shows a huge mushroom cloud and we may wonder whether it is an enormous rare dust wind cloud, or caused due to a nuclear or methane explosion," the video said.

An astronomer at the University of Southern Queensland, Australia, Jonti Horner, told the Express, "Fun as it would be to imagine that this is evidence of nuclear weapons on Mars, or even the impact of a chunk of Comet Siding Spring smashing into the planet, that's sadly just not the case."

According to Horner, the "cloud" is merely an optical illusion.

Brandenburg, whose next paper is set to be published in the Journal of Cosmology and Astroparticle Physics, claims that Mars was once Earth-like with advanced civilizations like the ancient Egyptians. Brandenburg claims his theory is supported by the 'high concentration' of Xenon-129 in the Martian atmosphere, plus surface uranium and thorium, as seen by Nasa's Mars Odyssey spacecraft, according to Daily Mail.

Brandenburg also used data from his studies of two sections of the Red Planet to support his theories, including Cydonia, where the now-discredited "face on Mars" was discovered. Brandenburg claims the face is an ancient artifact from the Martians that previously inhabited the planet.

One of the alleged nuclear explosions occurred at Cydonia Mensa and a smaller explosion destroyed a civilization at a region called Galaxias Chaos, according to Daily Mail.

"Analysis of new images from Odyssey, MRO and Mars Express orbiters now show strong evidence of eroded archeological objects at these sites," Brandenburg wrote in an abstract, according to Daily Mail. "Taken together, the data requires that the hypothesis of Mars as the site of an ancient planetary nuclear massacre must now be considered."

Brandenburg asserts the Fermi Paradox - why, if there is life out there, have we not run into any alien life forms - could be explained by his theory. Or, as Eric M. Jones wrote in "An Account of Fermi's Question," "Where is Everybody?"