Context

• In a new milestone in lunar exploration, NASA said that it’s Lunar Reconnaissance Orbiter (LRO) spacecraft had found evidence that the Moon’s subsurface might have greater quantities of metals such as iron and titanium than thought before.
• The metallic distribution was observed by the Miniature Radio Frequency (Mini-RF) instrument aboard the

What NASA has found

• In order to understand the origins of the Moon, scientists have for years explored the presence of metal deposits on the satellite comparative to Earth.
• As more data has become available over time, researchers have been able to further refine their hypotheses.

Mini-RF instrument

• Out on a mission to look for ice in polar lunar craters, the LRO’s Mini-RF instrument was measuring an electrical property within lunar soil in crater floors in the Moon’s northern hemisphere. The property, known as the dielectric constant, is the ratio of the electric permeability of a material to the electric permeability of a vacuum.

What the discovery means

• According to the NASA press release, the findings raise the possibility that the dielectric constant increased in larger craters because the meteors that created them dug up dust containing iron and titanium oxides from beneath the Moon’s surface. Dielectric properties are directly linked to the concentration of these metal minerals.
• If true, this logic would imply that beyond a few meters of the Moon’s upper surface– which relatively has lower metal deposits– lie large unknown quantities of iron and titanium oxides.
• The Mini-RF findings were backed by metal oxide maps from the LRO Wide-Angle Camera, Japan’s Kaguya mission and NASA’s Lunar Prospector spacecraft, which showed that larger craters with their increased dielectric material were also richer in metals.
• The maps suggested that more quantities of iron and titanium oxides were dug up from 0.5 to 2 km below the Moon’s surface as compared from the first 0.2 to 0.5 km.

The Moon formation hypothesis

• The most popular theory about the Moon’s creation is that a Mars-sized protoplanet collided with newly formed Earth around 4.5 billion years ago, breaking off a piece of our planet that went on to become its satellite.
• The hypothesis is also backed by substantial evidence, such as the close resemblance between the Moon’s bulk chemical composition with that of Earth.
• However, it is also known that Earth’s crust has lesser amounts of iron oxide than the Moon– a finding that scientists have been trying to explain.
• Now, the new discovery of even greater quantities of metal on the Moon makes their job even more difficult. “It really raises the question of what this means for our previous formation hypotheses,”