The baby is nearly thirty months, not truly a baby any more. He can climb stairs, pedal his tricycle, put words together in groups, although only his mother is very good at understanding him. He pronounces words using only half of his mouth, making the sounds fluffy and intimate. Only if you spend a lot of time with him will you understand his way of speaking. His mother likes this. It’s nice for her that they have this almost secret communication. She’s the one who explains the world to him. She knows that soon he’ll get better at speaking, and soon enough he’ll be at pre-school, and he’ll have other people to explain, and he’ll need her less and he won’t want her so much and this soft time they’re sharing will change into something else.

His mother is in the box room where he sleeps. She’s going to pull the curtains across so that he can go to bed. The moon tonight is huge. The room is submerged in white light from the moon. Shadows are deeper. Silence is thicker. She pauses in the moonlight, her hand on the curtain.

‘What that?’ the baby says.

‘The moon?’ says his mother.

‘What that?’ the baby says.

His mother tries to explain the moon. She tells the baby the story of the rabbit who lives there. The baby sits on his bed in a ray of moonlight, not understanding.

His mother points out the pits of craters in the moon. She tries to explain where the moon is, how it pulls on the Earth’s water making tides. She swishes her hands to show tides rising and falling.

‘Waves,’ says the baby.

‘Not waves, tides,’ says the baby’s mother. She tells the baby that people used to think that there was a man on the moon. She points at his eyes and mouth in the shadows of the craters. She tells the baby that there is a side of the moon that is always in darkness, and that broken dreams fly there to rest.

The baby’s eyes are round and clear. His mother sees stars and the dark deep blue night reflected in them. She squeezes the baby with a hard un-nameable feeling.

‘Mummy what that?’ says the baby pointing at the moon.

‘It’s the moon, baby,’ says the mother, pulling the curtain across.

Thousands of years earlier a woman uses a lump of chalk to draw a round shape on a wall of her cave dwelling as her baby rolls on an animal skin, flickered with firelight.