This Rare Meteorite Found on Earth Could Be Traced to Mercury’s Origins

Geologists have discovered that Mercury's composition a few billion years ago was that of an extremely rare meteorite found on Earth.

More than four billion years ago, the Solar System was in pure chaos. Little gas and dust particles collided and formed giant meteoroids that eventually crashed into each other to form planets. According to scientists, shortly after the formation, these planets were molten balls of fire that took millions of years to cool.

Recently, geologists from the Massachusetts Institute of Technology (MIT) were able to trace a bit of Mercury's cooling history and discovered that over 4 billion years ago, immediately after the planet formed, its core temperatures dropped by 240 degrees Celsius.

Also, by examining the composition of lava deposits found on the planet's surface and the rapid cooling rate that occurred, Mercury most likely had the composition of an enstatite chondrite, a very rare meteorite that was found on Earth.

This discovery, according to Timothy Grove of the MIT's Earth, Atmospheric and Planetary Sciences department, could be vital for tracing our own planet's early formation. Since Mercury has a less dymanic interior than that of the Earth (water played a major part in the difficulty of uncovering the past), it is clearer and more definite on how fast the planets must have cooled off in the early parts of the Solar System's history.

The analysis, published in the Earth and Planetary Science Letters, was put together by Grove and his team of colleagues from prime universities in Germany and Belgium using data collected from NASA's MESSENGER spacecraft's orbit of Mercury from 2011 to 2015. The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) probe collected measurements of the chemical composition of the planet with every flyby and produced images that showed lava deposits of over a kilometer thick that covered Mercury's surface.

Since then the team did multiple observations and studies on the data, and were able to conjure an initial understanding of Mercury's beginnings. The results, however, are not final and continue to be a work in progress, which the team think could take a long time, even years.