Water is From the Moon,
Diamonds are From Mercury:
This Week in Space

Water from the Moon

In recent years, the search for water on the Moon has primarily focused on its south pole, where both indirect evidence and direct measurements suggest the likely presence of ice beneath the surface, especially within permanently shadowed craters. However, new findings from China's Chang’e-5 probe, which collected soil samples from the Moon in 2020, raise the possibility that water may also be present on the Moon not just in the form of ice, but also in sunlit areas. 

The Chinese spacecraft landed in the "Ocean of Storms," located in the northwest of the Moon's near side, and brought 1,731 grams of lunar soil samples back to Earth. This mission made China the third country to successfully return samples from the Moon, after the United States and the Soviet Union. It was the second successful uncrewed lunar sample return and the first since 1976.

The samples were analyzed by researchers from the Chinese Academy of Sciences, who discovered a previously unknown mineral, naming it Changesite-(Y), as well as two new forms of titanium dioxide (Ti2O). In a recent paper published in Nature Astronomy, the researchers reported the discovery of another mineral, with a water-containing crystal structure, temporarily naming it ULM-1, which stands for "Unknown Lunar Mineral 1. Each particle of this mineral is surrounded by six water molecules trapped within the crystal structure, accounting for 41 percent of the crystals' mass. The other components of the crystal include magnesium, chlorine, and ammonia (NH4). The research team ruled out the possibility that the crystals were a byproduct of the heat and gases emitted by the lander's engines, partly by analyzing the isotopic composition of the elements.

Minerals previously unknown to science, including one that contains water. Illustration of the Chang’e-5 lander on the Moon | Source: NASA

The samples collected by astronauts during the six manned landings on the Moon as part of the American Apollo, as well as samples collected during the Soviet Union’s uncrewed Luna missions in the 1970s, suggested that the Moon’s soil was dry and lacked water. However, advancements in material composition analysis over the past two decades have enabled the detection of water in some lunar samples, such as water molecules or hydroxide ions (OH-) within volcanic glass crystals formed during the Moon’s early history. The novelty of the current discovery is the identification of water within a different type of crystals—hydrated salts, which are crystals that contain water. Moreover, this is the first time water has been detected in this specific region, north of lunar latitude 43°, which is roughly halfway between the equator and the pole, and further north than any other region from which lunar samples have been collected.

According to the researchers, the findings corroborate previous infrared radiation measurements suggesting water content in the lunar soil. They also challenge the hypothesis that water molecules or hydroxide ions found in certain lunar crystals were formed as a result of impacts from charged solar wind particles.  The mineral's composition, particularly the chlorine isotopes it contains, suggests these crystals formed through volcanic activity on the young Moon, trapping water present at that time and preserving it for billions of years.

Will the discovery impact manned missions? Not immediately. Even if it is confirmed that there is a significant amount of hydrated salts on the Moon, extracting water from these crystals would require complex, expensive equipment and considerable energy. In contrast, extracting water from ice—which is likely relatively abundant near the surface at the poles—is expected to be much simpler and more practical. Nonetheless, the discovery of water- and ammonia-containing crystals adds another piece of the complex puzzle of understanding the Moon’s formation and the events that have shaped it throughout its subsequent geological history.

Confirmation of previous findings: A short video from the WION channel about the research and the Chang’e-5 mission:

Mercury's Hidden Diamonds

Mercury, the smallest planet in the solar system and the closest to the Sun, exhibits several unique characteristics compared to other rocky planets. It lacks an atmosphere, has a very dark surface, and measurements indicate that it has an exceptionally dense core. Additionally, it appears to have cooled more rapidly after its formation. Another notable feature is the presence of graphite patches on its surface, which are believed to be remnants of a carbon-rich magma ocean that existed during the planet’s early history.

Now, researchers from China and Belgium analyzing data from the American MESSENGER spacecraft (which studied Mercury until 2015), have reached the conclusion that Mercury might hold significant value due to a diamond layer about 15 kilometers thick beneath its surface. This conclusion emerged from a study that reassessed the planet’s mass distribution, revealing that its mantle is much thicker than previously assumed.

"We calculate that, given the new estimate of the pressure at the mantle-core boundary, and knowing that Mercury is a carbon-rich planet, the carbon-bearing mineral that would form at the interface between mantle and core is diamond and not graphite," said Olivier Namur, associate professor at KU Leuven, Belgium.

To examine these processes, the researchers conducted laboratory experiments using a large-volume press to mimic the high-temperature and high-pressure conditions in Mercury's mantle. They subjected silicate compounds to extreme pressures and temperatures—over 2,000 degrees Celsius—to study how these conditions influence material formation in the mantle. Their computer simulations also supported the idea that diamonds could form under such conditions.

The researchers hypothesize that the diamonds formed under the extreme heat and pressure conditions of Mercury's core. However, being less dense than the core's metals, they floated upwards until reaching the mantle boundary, where a diamond layer gradually developed, reaching about 15 kilometers in thickness. For those dreaming of mining these diamonds, an immense challenge awaits: this layer lies more than 400 kilometers beneath the surface, requiring passage through the planet's rocky crust and the mantle layer located beneath it.

Despite the unlikely prospect of mining these diamonds,  the researchers hope their findings as well as future follow-up research will enhance our understanding of this intriguing planet. "A major question that I have about Mercury's evolution is why the major phase of volcanism lasted only a few hundred million years, much shorter than other rocky planets," said Namur. "This must mean that the planet cooled down very fast. This is partly related to the small size of the planet, but we are now working with physicists to try to understand if a diamond layer could have contributed to very fast heat removal, therefore terminating major volcanism very early." Some answers, the researchers hope, might be provided by the European-Japanese BepiColombo spacecraft, launched in 2018 which is expected to enter orbit around Mercury late next year to help study its internal composition.

 To reach the diamonds, one would have to travel more than 400 kilometers deep. Illustration of the diamond layer (below) against the backdrop of Mercury's surface | Illustration: Robert Lea (created with Canva)/NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Budget Cuts Threaten The Future of Veteran Observatory

NASA scientists warn that the agency may not be able to continue operating the Chandra X-ray Observatory if proposed budget cuts of approximately 40 percent are implemented in 2025. The Chandra telescope, which has been capturing X-ray images of the cosmos since its launch in 1999, is marking 25 years of operation with the release of a series of stunning images based on its observations.

The agency has formed a committee to review budget cuts across its programs due to an anticipated billion-dollar reduction in its scientific activities budget for the coming year.  The committee has recommended reducing the operational budget of the Chandra telescope by 40 percent, along with a 10 percent reduction in the budget for the operation of the veteran Hubble Space Telescope.

Astronomers have warned that the practical implication of such a significant budget cut would be the cessation of Chandra's operations, a concern shared by Patrick Slane, director of the Chandra X-ray Center. In an open letter, Slane wrote, “...These reductions compromise the ability to continue the Chandra mission.” He explained that as the telescope ages, its cooling systems are no longer as effective, but thanks to the team's innovative maneuvers and ideas, they have kept it operational with minimal efficiency loss. However, maintaining this with a drastic budget reduction would be unfeasible.

The proposed budget cut would reduce Chandra's annual operating budget from approximately 69 million dollars by about $20 million next year. The committee noted that while this would significantly reduce observing time with the telescope and lead to the shutdown of some of its instruments, partial use of the telescope would still be possible. Nevertheless, NASA is currently exploring alternative solutions to mitigate these cuts and has not yet abandoned efforts to reduce the anticipated budget reductions. In preparation for the potential impact, both the Chandra X-ray Center, which operates the Chandra X-ray Observatory, and the Space Telescope Science Institute (STScl) which operates the Hubble and James Webb Space Telescopes, are preparing for possible layoffs in the next fiscal year.

25 years of scientific discovery could come to an end due to budget cuts. The Chandra X-ray Observatory in space | Illustration: NASA/CXC & J. Vaughan