Physicist Stephen Hawking died yesterday at the age of 76. In the latter stages of his illustrious career, Hawking devoted a considerable amount of time and effort to issuing warnings of future threats - from the perils of climate change and nuclear war through to artificial superintelligence and alien invasions. And for this he was often ridiculed. But here's the thing: Hawking was right - and it would be incumbent upon all of us to heed his advice.