Scientists studying Mars have uncovered an unexpected finding deep within its core. Through data collected from NASA’s InSight lander, researchers discovered that Mars contains a solid inner core about 600 kilometers (373 miles) in diameter. This is surprising because earlier theories suggested that the Martian core was soft throughout. According to Huixing Bi, a seismologist at the University of Science and Technology of China, a solid inner core contradicts the common belief that Mars’s core is primarily made up of lighter elements that keep it molten.
For several years, scientists have used InSight’s seismometer to create a detailed map of Mars’s interior. This lander, active from 2018 to 2022, captured waves from quakes and meteorite impacts, allowing researchers to analyze how these waves travel through different materials inside the planet. It’s somewhat like using acoustic waves to perform a planetary X-ray.
This extensive mapping revealed that Mars has a structure similar to Earth: a hard crust, a molten mantle, and a core. However, key differences remain. Mars currently lacks a global magnetic field, hinting that it once had one, powered by a dynamo effect from its core. Unlike Earth, which maintains its magnetic field because of specific processes, Mars’s core dynamics seem very different.
To gather seismic data on Mars, researchers had to work with events from a single location. They identified 23 significant impact events, allowing them to analyze how seismic waves traveled through Mars’s inner core. Their findings indicate multiple waves, reinforcing the idea of a solid inner core.
Interestingly, Mars’s core composition differs from Earth’s. While similar in being primarily iron, it contains more sulfur, oxygen, and carbon. This mixture should theoretically keep the core molten, given Mars’s high internal temperatures. This discrepancy has puzzled scientists.
The data revealed distinct seismic waves traveling through Mars, such as PKiKP and other related phases, confirming the solid inner core’s existence. However, understanding why this solid core exists at all is challenging. More modeling is needed to delve into the temperatures and pressures that could create such a solid structure.
This discovery opens new avenues for research on Mars’s history. Understanding the solid inner core could provide insights into how the planet lost its magnetic field and how rocky planets evolve. As Bi and the team noted, “The size and attributes of Mars’s inner core are crucial for understanding the planet’s thermal and chemical evolution.”
This groundbreaking research was published in Nature. For further details, readers can explore the original study here.
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