An insect is more complex than a star..and is a far greater challenge to understand.

The carbon dioxide concentration in the atmosphere is measured. It's uncontroversial. It's going up. We know that has a tendency to warm the atmosphere and we should be worried about that.

In the beginning there were only probabilities. The universe could only come into existence if someone observed it. It does not matter that the observers turned up several billion years later. The universe exists because we are aware of it.

If we ever establish contact with intelligent aliens living on a planet around a distant star ... They would be made of similar atoms to us. They could trace their origins back to the big bang 13.7 billion years ago, and they would share with us the universe's future. However, the surest common culture would be mathematics.

The extreme sophistication of modern technology - wonderful though its benefits are - is, ironically, an impediment to engaging young people with basics: with learning how things work.

One of the computer models for a four degree temperature rise would give rise to a 10 degree temperature rise in Africa. And bear in mind also that in the depth of an ice age the mean temperature drop compared to the present was five degrees.

Science isn't just for scientists - it's not just a training for careers.