Despite evidence to the contrary from lunar rock samples gathered on an Apollo mission, the common belief among researchers is that the moon is dry.
However, data from recent images of a crater on the moon indicate a high level of hydroxyl molecules which point to the existence of magmatic water.
First things first, what is magmatic water? Magmatic water is exactly what you think it would be: water that comes from magma. But we’re Hopkins students and that definition will not satisfy. Magmatic water is the water that exists in equilibrium with magma that is released to the atmosphere during a volcanic eruption. It may also be released by hydrothermal fluids during the late stages of solidification of a planet’s crust.
This finding is of particular interest because it gives important insight into the internal composition of the moon. With this information in hand, a better understanding of where the moon came from may be within reach.
The commonly accepted idea is that the moon originated from a huge collision between two planetary bodies (one of which was a proto-earth) in the early formation of the solar system. As a result of this collision, pieces of proto-earth flew off and coalesced into a new body, which became the moon we all know and love.
This theory implies that the moon and the Earth were of one original body. Analysis of moon rocks collected from an Apollo mission show that the earth and the moon have the same isotopic signature thus indicating that moon and the Earth have similar composition. Furthermore, a study released from Caltech in 2007 indicates that the probability of the earth colliding with another planetary object of similar composition to be less than one percent.
The eerily similar compositions and isotopic makeup of our home planet and our satellite cannot be ignored. A new theory was proposed in 2012 in a paper called “Forming a moon with an earth-like composition via a giant impact” by R.M. Canup. This theory, much like the previous theory, involves the collision of two bodies. However, unlike the first theory, this theory proposes that the two bodies collided not once but twice.
The magmatic water was found on a type of rock called “norite,” which forms when magma ascends from within a planet and crystallizes before it gets to the surface. What is more exciting is that the existence of norite is not limited to the one crater, named Bullialdus in which it was originally located. In fact, this norite rock can be found in many other craters on the moon.
Researchers knew about the existence of water on the moon before this discovery though. But the moon is not the only other body our solar system that has water. A prime example of another body with water is Europa. Europa, the largest moon of Jupiter, has a thick shell of ice believed to be many kilometers deep. In addition to this, the constant tugging and forces between Europa, Jupiter and the other moons of Jupiter are believed to create a tremendous amount of heat within Europa. This leads to the possible existence of vast oceans under Europa’s icy surface.
In addition to Europa, researchers know of the existence of water on another moon in the solar system; Enceladus. Enceladus is a moon of Saturn and, much like Europa, has a sheet of ice, albeit much thinner, under which there is a huge body of water. One of the more beautiful aspects of Enceladus are the geysers made of ice. These geysers are the result of internal energy that is applied to the thin ice layer.
Water also exists on other planets in our solar system. For example, researchers know it to be present in the polar regions of Mercury which are permanently in shadow. This is particularly interesting because Mercury is in fact the closest planet to the Sun. Water also exists as ice on Uranus, Neptune, and our now estranged planetary brother Pluto.
All of this being said, the implications of magmatic water on the moon cannot be overlooked as it gives a deeper understanding into its origins and implications for life elsewhere in our universe.