Humans on Earth risk being wiped out by aliens in a huge nuclear explosion

Illinois, USA: That's according to plasma physicist Dr John Brandenburg, who believes rowdy inhabitants of Mars were blasted to smithereens by an intelligent alien race.

He says it is possible the Mars attack came from a force "hostile to young, noisy, civilizations such as ourselves".

The theory, which was heard at the Meeting of the American Physical Society in Illinois on Saturday, is based on the high concentration of Xenon-129 in its atmosphere.

Dr Brandenburg also points to uranium and thorium on the surface, spotted by Nasa's Mars Odyssey spacecraft.

Although these are natural materials found everywhere, he is adamant their presence is the result of a thermonuclear explosion that destroyed the Martians.

He says Mars once had a climate similar to the one on Earth, and was home to plant and animal life - intelligent life would have been about as advanced as the ancient Egyptians.

Writing in the abstract, Brandenburg warned of the chances of a similar attack on our own planet - and suggested we travel to Mars for research purposes.

He said: "Providentially, we are forewarned of this possible aspect of the cosmos.

"The author therefore advocates that a human mission to Mars is mounted immediately to maximise knowledge of what occurred."

The theories are complied in a talk entitled Evidence of Massive Thermonuclear Explosions in Mars Past, The Cydonian Hypothesis, and Fermi's Paradox.

“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," Dr Brandenburg told the Motherboard website.

“It is possible the Fermi Paradox means that our interstellar neighborhood contains forces hostile to young, noisy, civilizations such as ourselves,"

"Such hostile forces could range from things as alien as AI ‘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.”