I think Newton would be the greatest scientist who ever lived.

The energy necessary to create a wormhole or to wrap time into nuts is incredible. It's not for us. It's maybe for our descendants who have mastered the energy of this technology. So if one day, somebody knocks on your door and claims to be your great great great great granddaughter, don't slam the door.

It's humbling to realise that the developmental gulf between a miniscule ant colony and our modern human civilisation is only a tiny fraction of the distance between a Type 0 and a Type III civilisation - a factor of 100 billion billion, in fact. Yet we have such a highly regarded view of ourselves, we believe a Type III civilisation would find us irresistible and would rush to make contact with us. The truth is, however, they may be as interested in communicating with humans as we are keen to communicate with ants.

What differentiates human from lower-animal consciousness is time. You can't explain the concept of "tomorrow" to your dog. Our consciousness is dominated by time - We're constantly running simulations of the future. Our brain is a prediction machine. The hallmark of intelligence, indeed of genius, is the number and complexity of the feedback loops we use in predicting the future.

What we usually consider as impossible are simply engineering problems... there's no law of physics preventing them.

Until computers and robots make quantum advances, they basically remain adding machines: capable only of doing things in which all the variables are controlled and predictable. Robots are bad at pattern recognition and certainly at common sense. That's why computers can beat humans in chess but can't have even a basic conversation with a six-year-old.

So often, science fiction helps to get young people interested in science. That's why I don't mind talking about science fiction. It has a real role to play: to seize the imagination.