Seeing red

Ten astronauts train for mission to Mars after microbial life signs

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isn't science fiction, but ancient memory. Mythologists point out that extraterrestrial creatures have been depicted in ancient texts often described as "fallen angels".

In the Biblical book of Enoch, they are called the Watchers, and similar stories appear in ancient Jewish texts, the Book of Jubilees and the Damascus Document.

The idea that there was once an advanced civilisation on Mars has caused many to speculate on objects shown on photos of the planet's surface, taken by the Nasa rovers.

Some believe they have seen half-buried statues or other artificial structures, including what some people say looks like a Buddha figure and the ruins of an Inca-like city.

Author Mike Bara is among those who hold the belief dismissed as fantastical by most cosmologists - that Martians, escaping a catastrophe on their planet, brought life to Earth.