There May be Water on the Moon – or More Accurately, in it
New findings show that there may be water on the moon underneath the desolate exterior, and no one is sure how it got there.
Researchers studying the Moon have uncovered evidence that hints at a huge amount of water lying just under the surface. And if there is indeed water on the Moon, that potentially makes colonization all the more possible, and it shows that water may be more prevalent in the solar system than we used to believe.
It has generally been assumed that the Moon was a barren, lifeless rock. The lack of any substantial atmosphere, temperature extremes, and lack of low gravity meant that retaining water molecules was extremely unlikely. There was thought to be a small amount of water in the form of ice on its polar caps, a hypothesis proven in 2009 when NASA crashed the LCROSS probe into the Moon’s south pole, but only trace amounts. The discovery was considered significant, but it was also thought to further prove a long held theory that trace amounts of water located all over the lunar surface were there due to external forces, namely solar winds that initiated a chemical reaction that created the water.
A new study by planetary researchers from Brown University, however, suggests that the water may have been there all along. And not just trace amounts, but vast reservoirs hidden under the surface.
The evidence comes from lunar rocks known as pyroclastics, which are found throughout the Moon’s surface and originated from the Moon’s mantle. Not only does that change how we think of the Moon, it changes our theory of how the Moon may have formed.
NASA has had possession of several pyroclastic rocks since the Apollo missions brought them back. Researchers discovered trace amounts of water, and some even contained as much H2O as most rocks on Earth do. That didn’t necessarily mean much though, at least not in small numbers. It did, however, give researcher Shaui Li – a planetary scientist and the study’s lead author – an idea.
Li used the special equipment on India’s Chandrayaan-1 spacecraft, known as the Moon Mineralogy Mapper (M3), which is designed to capture near-infrared light bouncing off the lunar surface. Different reflections signify different chemical characteristics. The M3 was able to identify the traces of water on the poles, but it wasn’t able to do the same on the rest of the Moon due to the heat; daytime temperatures reach 260 Fahrenheit, which can distort the results. Li and his team found a way to counteract that heat, which led to the discovery that the Apollo findings were not unique. The pyroclastic rocks were not nearly as rare as initially thought. Instead, they are scattered throughout the Moon, which meant that rather than just a few tiny, ancient traces of water, under the surface – where the rocks initially came from – there must be water.
“Almost all examined pyroclastics show enhanced water features, supporting that the lunar mantle is ‘wet’ at a global scale,” said Li.
Roughly 4.5 billion years ago, a Mars-sized asteroid struck the Earth, leading to the creation of the Moon. For billions of year after, the Moon was racked with lunar eruptions that ended roughly 1 billion years ago and spewed forth pyroclastic rocks. Li’s new study suggests that either at some point a significant amount of water became trapped in the Moon’s molten mantle, where it remains.
“The distribution of these water-rich deposits is the key thing,” Ralph Milliken, a planetary scientist and co-author of the study said in a statement. “They’re spread across the surface, which tells us that the water found in the Apollo samples isn’t a one-off. Lunar pyroclastics seem to be universally water-rich, which suggests the same may be true of the mantle.”
The discovery raises some interesting questions as well – namely, where did it come from. The two most likely theories at the moment are that an asteroid or comet carrying the water impacted with the Moon back when it was still solidifying. The other theory is that the water was present back when the initial object hit Earth, and somehow it survived over billions of years, even as the Moon was still hot and volcanic.
More research will be needed, including work that will require people to actually go to the Moon.
The real potential of this discovery, however, may be for future colonization. If the water can be accessed and used in one form or another, it would make settlement on the inhospitable surface much easier (relatively). With luck, humans will return to the Moon within the next decade. When they do arrive, we should find out more.