There is a moment, presumably, just before the engines ignite, when even the most committed astronaut thinks: what on earth am I doing? But then, if they take a moment to look out of the portal at what is happening on the surface of this ball of rock and water we call home – well, who can fault them for wanting to get as far away as possible?

Four astronauts left Earth yesterday, climbing aboard what is, in engineering terms, a controlled explosion and trusting it to hurl them away from the planet at speeds no living thing was designed to tolerate. You could call it brave or foolish. But consider the alternative. They could have stayed. They could have watched the climate data worsen quarter by quarter while the machinery of international response grinds and stalls. They could have followed the wars – the missiles falling on Ukrainian cities, the devastation in Gaza, death and destruction in Iran, chaos in the Straits of Hormuz and more – and felt that familiar mixture of horror and helplessness. They could have watched democracy, that fragile and still-young experiment, being stress-tested by autocrats in countries big and small.

Strapped to a rocket for a journey further from Earth than any human has ever gone before, suddenly, looks sensible.

I imagine that what they will find up there is not escape. Not safety. Something closer to its opposite.

From orbit, Earth looks like a thought someone had and then left out in the dark. A thin blue film stretched over rock and water, suspended in a universe that is almost entirely lethal. No atmosphere. No liquid water. No margin for error. The cosmos does not negotiate, does not hold summits, does not issue statements of concern. It simply is – vast, indifferent, and hostile to everything we are made of.

Astronauts who have seen this tend to describe the same thing. Not relief at the distance, but a kind of vertigo at the stakes. The overview effect, as it has come to be known, is the sudden, visceral understanding that borders are invisible from up there, that conflicts look like nothing against the curvature of a planet, and that the arguments consuming us – which party, which nation, which version of the future – are being conducted on a single, fragile, irreplaceable rock.

You cannot see a war from orbit. You cannot see a pipeline or a ballot box or a rising sea. You can only see how thin the blue line is. How little separates the world from the void.

It is, by all accounts, the most clarifying thing a human being can experience. The planet is worth the panic we feel about it. Democracy is worth defending because there is nowhere else to put it. The climate is worth every difficult, expensive, politically inconvenient decision, because that thin blue line is not decorative. That is the entire point.

They have ten days up there. I hope the view helps.

* Tom Reeve is a Liberal Democrat councillor in Kingston upon Thames