Learning about the universe can be life changing. When you realise that our galaxy is at least 100,000 light years in diameter, that it contains several hundred billion stars, most with planets, and when you learn that the observable universe may contain anything up to one to two trillion1 such galaxies you cannot pretend that you do not know this and retreat to some earlier period of knowledge to recover a state of innocence when you thought Earth was all that mattered. True, it is where our lives are based, but there are no words to describe how utterly insignificant the Earth is to the universe which contains it.