The Universe may perhaps be infinite, but even to distinguish this from a very large finite Universe would seem to be scientifically impossible. Yet objects such as comet Encke, used to illustrate Peter Coles' book review (“From here to eternity” Nature 441, 285; 2006), hardly encourage us to consider an infinite universe to be reasonable. Encke is a body in the Solar System, a few light-hours away. In fact, it is one of the closest comets to the Sun.

You might have pictured a distant galactic cluster, such as the Great Wall — perhaps 200–300 million light years away. But even that would be a finite distance, no closer to infinity than a walk across the road.