Thoughts on science and cosmology have been scarce on this blog, and I suspect things will not change, but did you know the Earth once had two moons? It seems somewhat far fetched, but perhaps no less so than our own existence.
Most scientists now believe the moon was formed as a result of a spectacular collision between Earth and smaller planet, called Theia. The theory even has a true Hollywood sounding name: Giant Impact Theory. Theia, it is supposed, was roughly the size of Mars and lingering in an unstable orbit between Mars and the Earth. Gradually, it was pulled towards us resulting in a terrific crash. I used to have a teacher whose peculiar threat to enforce discipline was ‘I’ll bang your two heads together.’ The idea was similar.
Parts of the Earth and parts of Theia shot into space, and the matter was then captured in Earth orbit. Within a week or so, the bulk of this matter had coalesced into what we now call the moon. However there was still significant debris hurtling around the Earth, rather like the rocks that circle around Saturn. Eventually this debris joined together like the left over dough when you’re making scones, and ever so gently, caught up with the half formed moon, attaching itself to create the whole moon. Study of moon rocks has proved that the far side of the moon is indeed different in composition to the near side.
But can you imagine what all of this intergalactic turmoil looked like standing in a field in Suffolk four and a half billion years ago? Rather disconcerting, I’d say. However until this week, I had not given any thought to how the moon was formed and I suspect you hadn’t either, which is why I thought it was worth sharing.
The moon has never ceased to full us with wonder and aspiration. And what better cue for Ted Hughes’ marvelous poem: Full Moon and Little Frieda. The night and it’s silence is evoked in the most skilful way, and it has things to say about creation, how language forms and the simple miracle of existence.