We now know why the moon has so much less bling than Earth.
Gold, platinum and other metals known as strongly siderophilic ("iron-loving") elements are far more abundant in the Earth's crust than in its natural satellite.
It may seem weird considering the shared (and violent) history of the two worlds. About 4.5 billion years ago, a Mars planet struck Theia into the proto-earth which burst huge amounts of material from both bodies into space. Some of these liberated things were incorporated into the shattered and battered land, and some confused to form the moon.
Related: How the Moon evolved: A photograph Timeline
But scientists do not believe that the very siderophilic elements (HSE & # 39; s) really were part of the mixture. These metals were probably delivered later by asteroid strikes; It has been unclear why the Earth has a larger share. Eg. Did the earth just get clobbered by some big HSE-rich rocks, while the moon managed to escape these catastrophic effects? Or has a relatively stable stream of smaller HSE bearing slogans preferably hit the Earth long ago, drawn by our planet's stronger gravity?
"This has been a major problem with how we understand the moon's accretion history," Qingzhu yin, professor of earth and planetary science at the University of California, Davis, said in a statement.
yin is a member of a research team that looked at this issue. The researchers ̵
The results suggest that the moon with its much weaker gravity compared to Earth's features has just not been very good at hanging on battered material, HSE included; many things are lost in space. In fact, the lunar "stroke condition" is approx. three times lower than previously assumed, the team found.
The researchers also estimated that HMS retention in the lunar crust and mantle probably started later than previously estimated – 4.35 billion years ago, around the time when the magma sea covered the moon cooled and solidified. HSE's been arriving before that time, probably sank and was incorporated into the lunar core, the researchers said.
These two factors can explain HSE's relative lethargy in the lobe and the mantle according to the team describing the results in a study released online today (July 10) in journal Nature .
"The beauty of this work is such that all these things come together nicely," said Yin. "We may have solved this problem, at least until someone finds new disagreements!"
Mike Wall's book about the search for alien life, " Out There " (Grand Central Publishing, 2018; illustrated by Karl Tate ) is out now. Follow him on Twitter @michaeldwall . Follow us on Twitter @Spacedotcom or Facebook .