An expert has warned that aliens could crush humans if a war erupted.
Nick Pope, who probed UFOs for the Ministry of Defence, issued a dire prediction for the human race in the event of war with extra-terrestrials and claimed that aliens could "crack the planet open like a nut".
Pope is quoted by the Daily Star newspaper as saying: "They will be millions, maybe a couple of billion years ahead of us and their technology will be indistinguishable from magic."
He continued: "Our fastest space probes that we have ever built, if we had pointed them at the star aside from our own Sun, they would take 75,000 years to get there.
"So if we are being visited, a civilisation that has figured out viable interstellar travel is going to be able to crack this planet open like a nut if they wanted to."