The Solar System formed from the collision of a molecular cloud of hydrogen gas and dust under its own gravity. Thus, it started forming the early Sun, Earth, and other planets. As a subject of fascination, scientists are still discovering how planets are actually built. Scientists continue to study planets to better understand our solar system.
Now, scientists at the Australian National University have studied Earth and generated the best estimate of its elemental composition. Through this study, they believe they can better understand how the Earth formed 4.6 billion years ago.
Dr. Lineweaver from the Research School of Earth Sciences said, “The four most abundant elements – iron, oxygen, silicon, and magnesium- make up more than 90 percent of the Earth’s mass, but working out exactly what the Earth is made of is tricky.”
“Seismological studies of earthquakes inform us about the Earth’s core, mantle, and crust, but it’s hard to convert this information into an Earth’s Elemental Composition.”
“Our deepest drilling has only scratched the surface down to 10 kilometers of our 6,400-kilometre radius planet. Rocks at the surface only come from as deep as the upper mantle.”
Scientists derived the data from a meta-analysis of previous estimates of the mantle and core, and a new estimate of the core’s mass. They mainly focused on getting realistic uncertainties so that their model can be used in future comparisons of the Earth with the Sun.
At first, scientists compiled, combined, and renormalized a large set of heterogeneous literature values of the primitive mantle (PM) and of the core. They then integrated standard radial density profiles of the Earth and renormalized them to the current best estimate for the mass of the Earth.
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Here, scientists mainly evaluated the following uncertainties: 1. the density profiles, 2. the core-mantle boundary, and 3. the inner core boundary. Later on, they used standard error propagation to obtain a core mass. They found that uncertainties in elemental abundances helped calibrate the unresolved discrepancies between standard Earth models under various geochemical and geophysical assumptions.
Professor Trevor Ireland said, “This will have far-reaching importance, not only for planetary bodies in our Solar System but also other star systems in the universe.”
Journal Reference
- Wang, H. S., Lineweaver, C. H., & Ireland, T. R. (2017). The elemental abundances (with uncertainties) of the most Earth-like planet. Icarus, 299, 460-474. DOI: 10.1016/j.icarus.2017.08.024
