For anyone living in the twilight world of the Earth, there must be something very reassuring about the discovery of a planet which could hold life in a zone between dark and light, hot and cold. It is in this intermediate part, say the scientists, that conditions could be right to provide the water and atmosphere necessary for life. Not necessarily a nice place to live or with beings to inhabit it, add the astronomers. But life nonetheless.

And why not? Down here on Earth, we know that it is in the time between day and night and the moments between hot and cold that man is most measured and calm. Like the potential inhabitants of this new planet, one of half-a-dozen round the red dwarf star Gliese in the constellation Libra only 20 light years away from Earth, we Brits know to reject extremes of any kind. Moderation in all things, including habitability.

"Terminator" is what the line between light and shade on Gliese 581g is known as, which may accurately describe the limits of the uninhabitable on either side but not the region in the middle. But then again it might at least suggest a name for the new planet – "Arnie" is the obvious one – as well as the right kind of dress to approach the place.