You cannot study other planets without referring to Earth and without applying the techniques and the insights of Earth science. And you cannot really do a good job understanding the Earth without the insights from planetary exploration.

When you think about alien intelligences making art, you then have to think about what art is and how bound up it is in the nature of consciousness. Why do we make art? And what can we expect to have in common with other creatures in universe?

Among the radio astronomers of SETI - the Search for Extraterrestrial Intelligence - it's only sort-of a joke that the true hallmark of intelligent life is the creation of radio astronomy.

Why should we consider defining intelligence as something global and as something that hasn't actually yet appeared on Earth? It may be useful for envisioning the future of our own civilization and any others that may be out there among the stars. It might give us something to strive for.

We always hear from newspapers that while people understand the environmental challenge, they are unwilling to stomach the solutions. The trouble is, we only ever hear about the solutions from the media, and for whatever reason, they are almost always caricatured beyond recognition. If there's no appetite for green, it's not surprising.

The main message of Climate Revolution is that climate change is caused by the rotten financial system we've got, designed to create poverty and rip off any profits for a small amount of rich people. Meanwhile, it destroys the earth.

It is personal - deep in my bones and my flesh - the knowledge that we squandered our chance to avoid the climate emergency; to act when it would have been so much easier, as we did to stop acid rain, to save the ozone layer.

There are environmental threats to health; there are internal threats to health - genetic conditions, viral threats, diseases like cancer and Parkinson's. And then there are societal and global ones, like poverty and lack of nutrition. And unknown viral threats - everything from a new kind of influenza to hemorrhagic fever.