Does the greater threat to Earth come with climate change or from space?
Ultimately, we feel small when we watch films about the Solar System and beyond. I think there’s a sense in which we feel detached from nature, and that would be a mistake. Science is an attempt to understand nature, of which we’re a part, and that’s vital for our survival. There is a legitimate question we could ask: how do planetary atmospheres evolve? What we’ve found is that planetary atmospheres are rather fragile things in a sense, and they can evolve in response to quite small changes, and we’ve seen that not only by measuring the Earth’s atmosphere and modelling it, but also trying to model Venus’ atmosphere. In particular where we also deploy our climate models, and also Mars’ atmosphere and how it lost its atmosphere, which is also a target for our climate models. Investigating the Solar System allows us to test our understanding of the Earth. That’s the point, because we have different laboratories, so that’s number one.
But number two, the threat of an asteroid strike, for example, is very real. It does happen. Carl Sagan – this is one of my favourite quotes, I always quote it – he said, “If the dinosaurs had a space programme, they’d still be around.” But he was making a serious point that we do live in a challenging environment, and the more we understand about it, and the more we develop our technologies, it may allow us to mitigate some of these threats. This makes it more likely we are able to survive. I think that’s also important. That’s not science fiction, it’s a real issue.