Sign up for CNN’s Wonder Theory science newsletter! Embark on an exploration of the universe with the latest news on fascinating discoveries, scientific advancements, and more. Brace yourself for an astonishing revelation: scientists have made an astounding discovery of a substantial amount of the rare helium-3 in volcanic rocks on Canada’s Baffin Island. This intriguing find lends support to the theory that this noble gas has been leaking from Earth’s core over millennia.
But that’s not all. The research team also detected helium-4 within these rocks. While helium-4 is commonly found on Earth, helium-3 is more prevalent in the cosmos, which is why scientists were taken aback by the larger amount they discovered on Baffin Island. The study detailing this discovery was recently published in the prestigious journal Nature.
Lead study author, Forrest Horton, associate scientist at the Woods Hole Oceanographic Institution, explained, “At the most basic level, there is little helium-3 in the universe compared to helium-4.” Horton elaborated, “3He is rare on Earth because it has not been produced in significant quantities and is lost to space. As Earth’s rocky portion stirs and convects like hot water on a stove top, material ascends, cools, and sinks. During the cooling stage, helium is lost to the atmosphere and then to space.”
Detecting elements that escape from Earth’s core provides valuable insights into the planet’s formation and evolution over time. The new findings not only contribute to our understanding of how our planet came to be but also fortify the existing hypothesis that it originated in a solar nebula, a cloud of gas and dust that collapsed due to the shock wave from a nearby supernova. This solar nebula is believed to have contained trace amounts of helium-3 that leaked from Earth’s core, supporting this theory.
Baffin Island, situated in Canada’s Nunavut territory, is the largest island in the country and the fifth-largest in the world. It first caught scientists’ attention in 2003 when a high ratio of helium-3 to helium-4 was detected in volcanic rocks by Solveigh Lass-Evans during her doctoral studies. These rocks hold the key to understanding the composition of a planet since they reflect the elements involved in its formation.
In 2018, Horton and his team embarked on their own research trip to Baffin Island. They studied lava that erupted millions of years ago during the separation of Greenland and North America, providing them with valuable insights into Earth’s core and mantle. The team traveled to this remote and surreal landscape by helicopter, braving towering cliffs, giant icebergs, and the presence of polar bears. The Qikiqtani Inuit Association and Nunavut Research Institute offered their support and protection during the expedition.
Surprisingly, the Arctic rocks analyzed by Horton’s team contained significantly higher levels of helium-3 and helium-4 than previous research had reported, and the measurements varied across the collected samples. Horton described their experience as discovering scientific treasures, with each rock revealing valuable insights. The team found about 10 million helium-3 atoms per gram of olivine crystals, where only about one helium-3 atom exists for every million helium-4 atoms.
“Our high 3He/4He measurements imply that gases, presumably inherited from the solar nebula during solar system formation, are better preserved in Earth than previously thought,” Horton revealed.
But how did the helium-3 make its way into these rocks? The answer lies in the history of the universe, starting from the big bang. When the universe was created, it unleashed a vast amount of hydrogen and helium. Over time, these elements became integrated into the formation of galaxies. Our solar system, which emerged 4.5 billion years ago, likely formed within a solar nebula. As the collapsing dust cloud gave rise to our sun and planets, helium inherited from the solar nebula got locked into Earth’s core.
As helium-3 leaked from the core, it ascended to the surface through the mantle, taking the form of magma plumes that eventually erupted on Baffin Island. During this eruption, most of the gases in the magma escaped into the atmosphere, but the olivine crystals that formed beforehand preserved the helium from deep within the Earth.
This research supports the notion that helium-3 has been leaking from Earth’s core for a long time, although the exact initiation of this process remains uncertain. Horton explained, “The lavas are about 60 million years old, and the ascent of the mantle plume took perhaps tens of millions of years. So, the helium we measured in these rocks would have escaped the core perhaps 100 million years ago or possibly much earlier.”
Fortunately, the helium leakage from Earth’s core poses no harm to our planet or the environment. This noble gas does not chemically react with matter, meaning it has no impact on humanity or the ecosystem.
In their future studies, Horton and his team aim to investigate whether the core also stores other light elements that could explain why Earth’s outer core is less dense than expected. “Is the core a major repository of elements like carbon and hydrogen, which are so important in terms of planetary habitability? If so, have fluxes of these elements from the core over (Earth’s) history influenced planetary evolution? I am excited to investigate links between helium and other light elements,” Horton concluded.
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