Nasa has been forced to confirm that there almost certainly isn’t a long-lost civilisation on Mars.

During a hearing in the US congress, high-ranking staff of the space agency were asked whether there might once have been people living on the red planet.

California Republican Dana Rohrabacher asked whether the fact that Mars once had a vastly different atmosphere meant that it could also have supported an entire civilisation that was now lost.

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“You have indicated that Mars was totally different thousands of years ago,” he said. “Is it possible that there was a civilization on Mars thousands of years ago?”

His question was answered by Kenneth Farley, who is a project scientist on the Mars 2020 rover mission and a professor of geochemistry at California Institute of Technology and was one of the scientists answering politicians’ questions.

He pointed out that the “evidence is that Mars was different billions of years ago. Not thousands of years ago”.

He also said that there is “no evidence that I’m aware of”, that the planet was once inhabited.

That wasn’t enough for Mr Rohrabacher, who asked: “Would you rule that out? See, there’s some people… Well, anyway.”

Professor Farley said that such a possibility was “extremely unlikely”.

It isn’t clear who Mr Rohrabacher was referring to when he suggested that “some people” think there was a civilisation on the planet. But there are a limited number of people who have proposed what they believe to be proof not only of ancient civilisations but existing ones – including .

Otherwise, hearing was mostly focused on Nasa’s plans for exploring Mars, which will include the search for life on the planet. Some tests have already indicated that Mars could be host to some life – though not a civilisation.

The mission will be launched in 2019 and arrive at Mars the following February. It will stay there – looking for life as well as conducting other work – for a Martian year, or roughly two Earth years.