Professor Hawking was a theoretical physicist, cosmologist, and author who was the director of research at the Centre for Theoretical Cosmology at the University of Cambridge before his death in 2018. His incredible scientific work included a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity and the theoretical prediction that black holes emit radiation, often called Hawking radiation. But he was also evidently intrigued as to how Earth’s final days might play out.
For decades he called for humans to begin the process of colonising other planets on the basis that we would eventually fall victim to an extinction-level catastrophe, such as an asteroid impact.
In 2016, he told the BBC: “Although the chance of a disaster to planet Earth in a given year may be quite low, it adds up over time, and becomes a near certainty in the next thousand or 10,000 years.
“We will not establish self-sustaining colonies in space for at least the next hundred years, so we have to be very careful in this period.”
The Cambridge physicist also regarded global warming as one of the biggest threats to life on the blue planet.
He feared human-created climate change would have severe consequences.
He said in 2017: “We are close to the tipping point where global warming becomes irreversible.
“Trump’s action could push the Earth over the brink, to become like Venus, with a temperature of 250 degrees, and raining sulphuric acid.”
But Prof Hawking was also concerned about the dangers that could arise from advances in artificial intelligence (AI).
In 2014, he said: “The development of full artificial intelligence could spell the end of the human race.”
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“If they’re interested in resources, they have ways of finding rocky planets that don’t depend on whether we broadcast or not.
“They could have found us a billion years ago.”
But others saw the logic in Prof Hawking’s comments.
Ian Stewart, a mathematician at Warwick University, commented: “Lots of people think that because they would be so wise and knowledgeable, they would be peaceful.
“I don’t think you can assume that.”
Professor Sir Martin Rees, the Astronomer Royal, believed Prof Hawking’s comments were taken too seriously over the years.
He said: “He had robust common sense, and was ready to express forceful political opinions.