Earth’s ability to sustain life depends a lot on volatile elements like carbon, hydrogen, sulfur and nitrogen that make up a large proportion of our atmosphere, allowing us to breathe and keep warm in cold space. In a new study from Rice University, CLEVER Planets PhD student Damanveer Grewal, Principal Investigator Rajdeep Dasgupta, Researcher Kyusei Tsuno and Postdoctoral scholar Chenguang Sun, with the help of Gelu Costin, suggest that most of these necessary elements may have been delivered to our planet when a Mars-sized planetary body smashed into early Earth more than 4.4 billion years ago.
The late addition of these volatiles via primitive meteorites has long been considered the main mechanism of volatile element delivery to Earth. But such a mechanism does not explain thegeochemically anomalous nitrogen content as compared to carbon. Therefore, the timing and delivery mechanism of these elements remained an unsolved mystery; this study provides that new information.
This study, published in Science Advances, incorporated results from experiments at high temperature and high pressure, simulating the conditions of magma ocean of a planetary embryo, which cooled and separated into a distinct outer crust and inner mantle layers above the core. These experiments explored the capacity of a planet with sulfur-rich core to distribute different elements in its different reservoirs. The experimental findings were factored into a computer model along with geochemical compositions and isotopic signatures, which, after over a billion simulations, determined the most likely culprit for delivery of life-essential materials to the proto-Earth: a Mars-sized embryonic planet with sulfur-rich core that impacted Earth and formed the Moon.
This discovery implies that, in terms of its habitability, a rocky planet need not have all necessary elements to produce and sustain life from its birth; it could undergo giant impacts from other planetary bodies that can alter its composition and make it more viable for hosting life.
Read more about this research update in Rice University’s press release here or read the publication here.
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Credit: Laura Carter