Sign up for CNN’s Wonder Theory science newsletter to stay updated on the latest discoveries and scientific advancements in the universe. CNN brings you fascinating news, including the recent finding that scientists have detected an unexpected amount of helium-3, a rare version of helium, in volcanic rocks on Baffin Island in Canada. This discovery supports the theory that helium-3 is leaking from Earth’s core over thousands of years. The research team also discovered helium-4 in these rocks. While helium-4 is common on Earth, helium-3 is more commonly found in the cosmos, making the presence of a larger amount of helium-3 in these rocks surprising. The study detailing this finding was recently published in the journal Nature.
Lead study author Forrest Horton, an associate scientist at the Woods Hole Oceanographic Institution, explains that there is a scarcity of helium-3 compared to helium-4 in the universe. This scarcity is due to the fact that helium-3 is not produced or added to Earth in significant quantities, and it is lost to space. As Earth’s rocky part moves and convects, similar to hot water on a stove, material rises, cools, and sinks. During the cooling process, helium is lost to the atmosphere and eventually to space.
Detecting elements that leak from Earth’s core provides valuable insights into the formation and evolution of our planet. The new findings support the hypothesis that our planet originated from a solar nebula, a cloud of gas and dust that collapsed due to the shock wave of a nearby supernova, which contained helium-3. Baffin Island, the largest island in Canada and the fifth-largest in the world, has been instrumental in these discoveries. In 2003, researchers first detected a high ratio of helium-3 to helium-4 in volcanic rocks on Baffin Island. These rocks have now revealed even higher measurements of helium-3 and helium-4 than previously reported.
Horton and his team conducted their research on Baffin Island in 2018, studying lava that erupted millions of years ago during the separation of Greenland and North America. They aimed to gain insights into the contents of Earth’s core and mantle, the solid layer beneath the surface. To access the remote landscape of Baffin Island, the researchers traveled by helicopter, encountering mountains, cliffs, icebergs, and polar bears. Local organizations provided them with access, advice, and protection. The Arctic rocks they examined contained valuable scientific information.
The measurements taken by the research team indicate that helium-3 is much scarcer compared to helium-4. About 10 million helium-3 atoms were measured per gram of olivine crystals found in the rocks. This high ratio implies that gases inherited from the solar nebula during the formation of the solar system are better preserved in Earth’s core than previously believed.
The presence of helium-3 in the rocks is a result of the cosmic abundance of hydrogen and helium after the big bang. Our solar system formed within a solar nebula approximately 4.5 billion years ago. As the nebula collapsed during a supernova, it created a spinning disk from which the sun and planets formed. Helium inherited from this nebula became trapped in Earth’s core as it formed, turning it into a reservoir of noble gases. Over time, helium-3 leaked from the core through the mantle as magma plumes, eventually erupting on Baffin Island. Only olivine crystals that formed before the eruption trapped and preserved the helium from deep within the Earth.
Although the exact time when helium-3 began leaking from the core remains uncertain, the lavas studied are approximately 60 million years old, indicating that the helium measured in these rocks escaped the core around 100 million years ago or possibly earlier. The leakage of helium from Earth’s core does not have any negative implications for our planet or the environment, as helium does not chemically react with matter.
The research team’s next step is to investigate whether the core contains other light elements, which could explain why Earth’s outer core is less dense than expected. Understanding the core’s composition and its relationship with other elements can offer valuable insights into the planet’s habitability and its evolution over time.
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