Ultimately, if you think about all the youth that everybody has mentioned here in Africa, if everybody is raising living standards to the point where everybody has got a car and everybody has got air conditioning, and everybody has got a big house, well, the planet will boil over - unless we find new ways of producing energy.

Jobs was brave enough to think differently, bold enough to believe he could change the world, and talented enough to do it.

Of course I have got concerns. Donald Trump and I differ on a whole bunch of issues.

As the world's largest economy and second-largest carbon emitter, as a country with unsurpassed ability to drive innovation and scientific breakthroughs, as the country that people around the world continue to look to in times of crisis, we've got a vital role to play. We can't stand on the sidelines. We've got a unique responsibility.

There are a lot of very religious scientists around. I think the problem here is that in our school systems, and to some degree - and this is where it is relevant - with school boards around the country that are mandating curriculums and textbooks, you start seeing this weird watering down of scientific fact so that our kids are growing up in an environment - and this connects to what I was saying earlier abou the media - where everything's contested. Where nothing is true.

I want every math teacher to know math. I want every science teacher to have expertise in science. I want them to know how to inspire and engage young people.

Sometimes we take somebody who's been in the trenches and fought the good fight and been steady for granted. Sometimes we act as if never having done something and not knowing what you're doing is a virtue.