Huge Secret Hidden in Mercury Possible Diamond Layer Discovered
TapTechNews August 3rd news, there may be a huge secret hidden in the smallest planet in the solar system. Scientists inferred from the data obtained by NASA's Messenger (MESSENGER) probe that there may be a diamond/diamond layer with a thickness of up to 10 miles (TapTechNews note: about 16.09 kilometers) hidden under Mercury's crust, and the relevant research results have been published in the journal Nature: Communications.
In fact, many features of Mercury have always puzzled scientists because it has many characteristics different from other solar system planets, such as the dark surface, the abnormally dense core, and the strangely prematurely ended Mercury volcanic activity period.
In order to better detect Mercury, NASA launched the first probe orbiting Mercury in August 2004 - Messenger. This mission ended in 2015. It successfully mapped the entire miniature world of Mercury and discovered a large amount of water ice in the polar shadow of Mercury, and also collected important data on Mercury's geology and magnetism.
Of course, there are also a lot of mysteries in Mercury, one of which is the graphite patch (a carbon allotrope) existing on Mercury's surface. Scientists speculate that there was once a carbon-rich magma ocean in Mercury's early history, and these magmas may have floated to the surface, thus forming this patch and giving Mercury a dark tone.
The same process may also lead to the formation of a carbon-rich mantle below Mercury's surface. They found that the planet's mantle is thicker than previously thought. The team behind this study believes that this mantle is not the previously speculated graphene, but another more precious carbon allotrope - diamond.
Olivier Namur, an associate professor at the University of Leuven and one of the team members, said: Based on the new pressure estimate at the mantle-core boundary and the knowledge that Mercury is a carbon-rich planet, we calculated that the carbon-containing minerals formed at the mantle-core interface should be diamonds, not graphite. Our research used the geophysical data collected by NASA's Messenger probe.
We think diamonds may form through two processes. The first is the crystallization of the magma ocean, but this process may only form a very thin diamond layer at the core/mantle interface, Namur explained. Secondly, and most importantly, it is the crystallization of Mercury's metal core.
Namur said that when Mercury was just formed (about 4.5 billion years ago), the planet's core was completely liquid and gradually crystallized over time. The exact nature of the solid phase formed in the inner core is not yet clear, but the research team believes that these phases should be low-carbon or carbon-poor.
He also mentioned: The liquid core before crystallization contains some carbon, so crystallization will lead to carbon enrichment in the residual melt. At a certain point, the solubility threshold is reached, which means the liquid cannot dissolve more carbon, and then diamonds are formed.
According to his idea, diamond is not as dense as metal. This means that in this process, it will float to the top of the core and stay at the boundary between Mercury's core and mantle. This will lead to the formation of a diamond layer about 1 kilometer thick, and then continue to grow over time.
The research team believes that this finding may help uncover other mysteries of this smallest planet in the solar system, including why its volcanic activity period ended so suddenly about 3.5 billion years ago.
One of my main questions about Mercury's evolution is why the main volcanic activity period only lasted for a few hundred million years, much shorter than that of other rocky planets. This means that this planet cools very quickly, Namur said. This is partly related to the small size of the planet, but we are now working with physicists to try to understand whether the diamond layer may help dissipate heat very quickly, thus leading to a very early end of volcanic activity.
Namur said that the next step of the team will be to study the thermal effect of the diamond layer at the mantle/core interface. This research can be supported by the data of the successor of Messenger.
We can't wait to wait for the first batch of data collected by BepiColombo in 2026 to improve our understanding of Mercury's internal structure and evolution, Namur concluded.