New research published earlier this week in the journal Nature has revealed that the Earth and other planetary objects formed during the early years of the solar system share similar chemical origins – a discovery that is in stark contrast to what scientists have believed for decades.
Using data collected through thermal ionization mass spectrometry, Audrey Bouvier, a professor and cosmochemist from Western University in Ontario, Canada, and Maud Boyet of the Magmas and Volcanoes Laboratory at Blaise Pascal University in Clermont-Ferrand, France, reported that Earth and several other extraterrestrial objects share identical initial Neodymium-142 levels.
Neodymium-142 (142Nd) is one of seven isotopes found in the chemical element neodymium, a metal that is widely distributed in the Earth’s crust and commonly used to create magnets for use in commercial products such as microphones and earbuds, the authors explained in a statement.
“How the Earth was formed and what type of planetary materials were part of that formation are issues that have puzzled generations of scientists,” said Bouvier, who is also the Curator of the Western Meteorite Collection as well as Canada Research Chair (CRC) in Planetary Materials at the university. “And these new isotopic measurements of meteorites provide exciting answers to these questions about our origins and what made the Earth so special.”
Explaining differences between Earth’s interior and chondrites
Research conducted 11 years ago revealed a slight variation in 142Nd between terrestrial rocks and chondrites, stone meteors believed to have been vital building blocks of our homeworld, the researchers explained. These findings were interpreted as a differentiation of the Earth’s interior and chondrites during the planet’s first 30 million years of existence.
“The isotopes of Nd were measured precisely in 2005 but in different materials,” Bouvier said in an interview with the Daily Mail Thursday. “The interpretation back then was that the difference between Earth and chondrites had to be the consequence of Earth’s differentiation into different internal layers (mantle, crust, core) very early in its history.”
However, in their newly-published study, she and Boyet demonstrated that the differences in these neodymium isotopes were actually present during the initial growth phase of the Earth, and were not introduced at a later time as initially believed. In fact, using new and improved methods of data collection, they learned that not all meteoritical objects in the solar system were exactly alike.
Specifically, their measurements revealed that while different objects found in the solar system contained both the elements neodymium (Nd) and samarium (Sm), there were slight variations in the isotopic compositions of those elements, suggesting that the solar system was not chemically uniform even during its earliest phases and that materials formed from earlier stellar generations were incorporated in different amounts when planets first formed.
“The Earth evolved from materials that were different or in different proportions than the ones that built other planets such as Mars,” Bouvier told the Daily Mail. “It took longer than we thought for the Earth to form and evolve but we find that both Earth and the moon share more and stronger similarities with their building blocks and chemical evolution.”
Image credit: Thinkstock