Explorations in time and space

Is this the best year ever for the exploration of the Solar System? The first detailed pictures and data of Pluto and its moons; The first landing on a comet; And yesterday's, not entirely unexpected, announcement by NASA that there is water on Mars in sufficient quantities to form streams and interact with the landscape in a similar manner to Earth. Any one of these would be jaw-dropping enough. We are becoming confident that we can understand - and see - processes going on 4 billion miles away.

And how ironic that if we look back a tiny amount in time - say four thousand years - we have almost no idea about what our ancestors were up to. Mrs C. and I spent the weekend on a fascinating tour of the prehistoric landscape of Wiltshire led by an experienced archaeologist. We looked at henges and barrows, marvelled at the intricate gold and bronze artefacts in the museums and pondered the meaning of such enigmatic shapes as the Stonehenge Cursus and Durrington Walls. And you can make up almost any story you like because nobody knows anything, they can only infer from the evidence, most of which relates to the dead. We don't know why they built Stonehenge or Avebury. We don't know why they buried people in long barrows, then switched to round. We don't know why they moved stones around inside the henges and what those stones meant to them, and why they ceased to use the sites hundreds of years before the Romans brought these islands into the modern historical era.

We do know that they aligned their buildings with the solstices and can infer, from the dating of the huge animal remains at Durrington, that they gathered in great numbers at the time of the winter solstice for feasting. What did they think as the sun rose on the shortest day of the year? Would it fail to return unless they implored it?  Did their ancestors live on up there, or on the Moon?

We know what the Moon is made of, and comets, and even that tiny remote Pluto has its own atmosphere, mountains and smooth plains. But why Wiltshire is covered with enigmatic monuments to a skilled people who, alas, left us not a word to tell their story - we are unlikely to discover.