Theoretical physicist Stephen Hawking says space travel provides "life insurance" for mankind. Reuters

Stephen Hawking has said space travel is essential for mankind's future as it helps drive scientific advances and provides a form of "life insurance" for the survival of the human race.

The world-renowned physicist was speaking exclusively to the Spanish newspaper El Mundo when he was asked if he believes investment in space exploration is worth it.

Many other scientists have said spending billions on space missions is wasteful, due to recent funding cuts. However, Hawking disagrees.

"Space exploration has driven and continues to drive major scientific and technological advances," he said, adding that it can represent a "life insurance" for our future survival as "it could prevent the disappearance of humanity by colonising other planets".

Hawking also spoke about his religious beliefs, confirming he is an atheist. Previously, he had talked about knowing the "mind of God", but also said the universe could have been created "out of nothing".

"In the past, before we understood the science, it was logical to believe that God created the universe. But now science offers a more convincing explanation," he said.

"What I meant when I said that we would know 'the mind of God' was that we would understand all that God would be able to understand if He existed. But there is no God. I am an atheist. Religion believes in miracles, but they are not compatible with science. "

The 72-year-old said he believes that one day, mankind will achieve a "theory of everything":

"I think we will get to understand the origin and structure of the Universe. In fact, right now we're close to achieving this goal. In my opinion, there is no aspect of reality beyond the reach of the human mind."