Cosmologist Stephen Hawking and Tesla CEO Elon Musk endorsed a set of principles that have been established to ensure that self-thinking machines remain safe and act in humanity's best interests. Machines are getting more intelligent every year and researchers believe they could possess human levels of intelligence in the coming decades. Once they reach this point they could then start to improve themselves and create even more powerful software, according to Oxford philosopher Nick Bostrom and several others in the field. In 2014, Musk warned that artificial intelligence has the potential to be "more dangerous than nukes" while Hawking said in December 2014 that AI could end humanity. AI could also help to cure cancer and slow down global warming.