The universe is a huge place. Three objects in the night sky, visible to the naked eye, can give us some impression of the dizzying depths of space. These three objects, the Moon, the Pole Star and the Andromeda galaxy belong respectively to the planetary, stellar and extragalactic domains. Light, travelling at 300,000 kilometres (186,000 miles) per second, takes one and a quarter seconds to reach us from the Moon, six hundred years from the Pole Star, and two million years to journey from the Andromeda Galaxy.

The universe is also ancient. Its past history is a series of overlapping epochs. Just a few thousand years encompass the historic past, and a few million take us back to the dawn of prehistory. Geologic history extends a few billion years into the past, whereas the cosmological history of the universe, takes us back fifteen billion years to the Big Bang itself.

The universe is full of delights. There are spiral galaxies and gaseous nebulas, faintly glowing mists set against the backdrop of deep space, multiple stars spewing out fantastic arcs of matter, and the fabulous landscapes of planets and their satellites. Humans have walked on the nearest object, the Moon. It always fills me with amazement when I see it in the early evening, between the first quarter and Full Moon, dominating the clear sky, as dusk begins.