Lost alien civilisation may have lived on Earth: Space scientist

A scientist has raised the theory that Earth was once inhabited by aliens billions of years ago. Photo/Getty

Our solar system may have once inhabited a now extinct species of extraterrestrial life according to a top scientist.

The space scientist said he believes an ancient alien species could have lived on Mars, Venus or even Earth before vanishing.

Professor James T Wright from Pennsylvania wrote an academic paper, titled Prior Indigenous Technological Species, raising the possibility that evidence of extraterrestrial life may lie in our solar system.

"A prior indigenous technological species might have arisen on ancient Earth or another body, such as a pre-greenhouse Venus or a wet Mars," he wrote in his paper.

However, Professor Wright said Earth's plate tectonics would have erased many traces of a civilisation from billions of years ago, leaving archaeologists just a handful of places where evidence may be found.

"Remaining indigenous technosignatures might be expected to be extremely old, limiting the places they might still be found to beneath the surfaces of Mars and the Moon, or in the outer Solar System," he added.

Professor Wright still remains optimistic alien evidence was likely to have been buried beneath the ground.

"Structures buried beneath surfaces might survive and be discoverable as long as they do not suffer a collision so severe that their artificial nature is obliterated."

"Merely destroying them would render them non-functional, but they might still be recognisably technological.

"We might conjecture that settlements or bases on these objects would have been built beneath the surface for a variety of reasons, and so still be discoverable today."

The astronomer suggested evidence of spaceships or ancient probes may still be floating in the Asteroid Belt covered in ice.