Not so—and this is one of the many shattering conclusions I take away on closing this book. Give or take a few billion years, ours is a very propitious time to be a cosmologist. Two trillion years hence, the universe will have expanded so far that all galaxies but the cosmologist’s own (whichever one it happens to be) will have receded behind an Einsteinian horizon so absolute, so inviolable, that they are not only invisible but beyond all possibility of leaving a trace, however indirect.

A marvellous afterword, but I'm cautious about such conclusions. 15 years ago we would come to quite a different conclusion. It may be that in another 15 years we will come to yet another conclusion.

The universe is possibly very, very young indeed compared to its possibly unlimited future. Far, far younger still is the science of cosmology! Until we have sorted out what the dark components of our universe really are, we don't know what the future might be on a scale of tens of billions of years, let alone trillions. And, there is always the discovery of X. What is X? I have no idea, but the history of cosmology shows that Xs turn up pretty often, and change everything.

Long-term forecasts for the universe remind me of long-term weather forecasts in the UK. It is a difficult business, such that the forecast for even a few days in the future can change on a daily basis. The forecasts can change so often that I long for a forecast-forecast that gives the chances of future predictions - what is the likelihood that tomorrow there will be a forecast for snow at the weekend?

Prediction is hard, especially when it comes to the future. It's probably far, far too soon to predict what the universe will be like in trillennia. It's probably too soon to predict what will be predicted in a decade.

But I can't wait for the book anyway.