These watery gems provide strong evidence that the inside of the moon was once gushing with liquid water. That’s in stark contrast to how most of us think about our dear old piece of cheese, as dusty and dry. So how much is a part per million? Parts per million ( or billion or trillion) are measures of concentration. They allow scientists to determine how much of a substance is in another substance, using a limited sample.
If the glass pebble were cut into a million pieces, only about 46 of them would be made of water. While this may seem mind-bogglingly small, the finding is tantalizing proof of water that must have once existed on the moon in ample supply.
Scientists detected the water by using a technique called secondary ion mass spectrometry (SIMS), and then confirmed then presence of hydrogen in the samples through rigorous testing.
The discovered water sheds new light on a widely accepted theory of moon formation, that a giant object slammed into the earth some 4.5 billion years ago, breaking off a molten chunk that cooled and created the moon. The impact of this collision would have quickly vaporized any water. Moreover, the findings indicate that water must have been present on earth before the collision.