Every generation has a few truly exceptional minds, and Stephen Hawking was one of the most brilliant we had to offer. When he passed away in 2018, the world lost one of the few people who probably could have thought of a way out of the mess that we've made of the world. But he may have left us one last gift, and that's a warning that the end is nigh. This is what he thought was going to happen. Just a few weeks before he died, he released a paper called "A Smooth Exit From Eternal Inflation?" and it's a strangely beautiful look at how he believed the universe began, grew, and will finally end. It's abstract and complicated stuff that even most scientists don't understand, and dissecting what it's all about isn't easy. At the heart of the matter is this: Stephen Hawking and paper co-author Thomas Hertog essentially speculate the end of the universe will be something of a relatively smooth transition into the after, and cosmologist Andrei Linde translated a bit of the heaviest stuff like this: "They argue that the end of eternal inflation (the expansion of the universe) may occur in a smooth way, and the variety of the possible outcomes is limited." That's vague, and a sort of anti-climactic end to the universe, but there's a good chance no one on Earth will be around to see it. When it comes to the end of our own world, however, Hawking made some incredibly dire predictions about it. Wired asked him about the relentless march toward developing artificial intelligence, and he warned it might mean the end of mankind in a way that we've long thought of as being science fiction. "The genie is out of the bottle. We […] need to be mindful of its very real dangers. I fear that AI may replace humans altogether. […] Someone will design AI that replicates itself. This will be a new form of life that will outperform humans." Speaking at a summit in Portugal in 2017, he warned that the rise of AI had the potential to be incredibly dangerous. He's spoken about it for years, and in 2014 told John Oliver: "Artificial intelligence could be a real danger in the not too distant future. It could design improvements to itself and outsmart us all" He foresaw not just autonomous robots but autonomous weapons, too, and when one of the most brilliant minds in the world warns that science fiction might become science fact, the rest of the species should probably listen. "Why should I not be excited about fighting a robot?" You would lose." He's also suggested we're in danger of destroying ourselves before we even get that far, and in 2017, he talked to the BBC about how we're doing it. A huge part of our mistakes involve climate change, and he cited US President Donald Trump's decision to withdraw America from the Paris Agreement as particularly worrying. He said: "We are close to the tipping point where global warming becomes irreversible. Trump's action could push Earth over the brink […] and [by] pulling out of the Paris climate agreement, Donald Trump will cause unavoidable environmental damage to our beautiful planet, endangering the natural world for us and our children." Hawking was absolutely not kidding around, and when he spoke at the Starmus IV Festival in 2017, he stressed how important it was that we find a way to colonize other planets if we want the human race to survive. Only the previous year, Hawking predicting that mankind had only about 1,000 years before the planet became incapable of supporting human life, and we needed to find a new place to live, pretty pronto. At the time, he was optimistic that mankind would get its act together, but by 2017, he revised his time frame to a mere 100 years. Some might be able to agree it was a rough year, but that rough? Hawking also made some other comments in 2017 that got almost just as much attention. At the Tencent WE Summit he predicted overpopulation and the subsequent energy consumption were going to get to an unsustainable point in just 600 years … give or take. Put it all together, and he paints a pretty dire picture of our world's future if things continue in the direction they're going. Overpopulation, climate change, energy consumption, artificial intelligence leading to a major war against machines … those are all things humans are doing to ruin the planet, but Hawking has also said there's the chance the end of the world is going to come from something well beyond the control of any human. During his talk at the BBC's 2016 Reith Lectures, he warned, "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 ten thousand years." "And pray that there's intelligent life somewhere out in space, cause there's bugger all down here on Earth"