Marsquakes Uncover Solid Inner Core and Ancient History of the Red Planet

Recent analysis of seismic data from Mars, collected by NASA's InSight lander, has provided groundbreaking insights into the planet's deep interior. Scientists have now confirmed the existence of a solid inner core within Mars, a discovery that fundamentally changes our understanding of the Red Planet's structure and its geological evolution. These findings are crucial for piecing together the formation story of Mars and, by extension, other rocky planets in our solar system.

Unveiling Mars' Hidden Depths

The InSight lander, which concluded its mission in late 2022, recorded hundreds of marsquakes over its operational period. These seismic waves, traveling through the planet's layers, acted like an ultrasound, allowing researchers to map the internal structure with unprecedented detail. The most significant revelation is a solid inner core, estimated to be approximately 600 kilometers (about 370 miles) in diameter. This solid core is surrounded by a molten outer core, similar in layering to Earth's core, though Mars' core is significantly smaller and less active.

Beyond the core, the research also shed light on Mars' mantle, the thick layer between the crust and the core. The data suggests that the Martian mantle may contain remnants of ancient cosmic impacts, possibly massive chunks of early solar system material that became embedded deep within the planet during its formation billions of years ago. This provides a unique window into Mars' violent early history and how it acquired its initial building blocks.

Comparative Planetology: Earth and Mars

The discovery of a solid inner core on Mars invites direct comparisons with Earth, which also possesses a solid inner core within a liquid outer core. Despite these structural similarities at their centers, the two planets have evolved very differently. Earth maintains a strong magnetic field and active plate tectonics, phenomena largely driven by its dynamic core. Mars, however, lost its global magnetic field early in its history, leading to a thinner atmosphere and a very different surface environment.

Understanding these subtle differences in core composition and dynamics helps scientists explain why Mars became the arid, seemingly geologically inactive world we see today, while Earth continues to be a vibrant, life-supporting planet. The data from InSight offers critical clues, suggesting that while the initial building blocks and internal layering might share commonalities, the subsequent processes diverged significantly.

What happens next

Scientists will continue to analyze the extensive data collected by the InSight mission to refine their models of Mars' interior. Future missions to Mars might incorporate even more advanced seismic instruments or even attempt to drill deeper into the planet's crust to gather direct samples. These ongoing studies will further enhance our knowledge of planetary formation, not just for Mars, but for exoplanets and other celestial bodies throughout the cosmos.