Mars, with its frozen expanse of red dust, gaping craters, and rocky terrain, holds many secrets beneath its wind-blasted surface. And NASA’s InSight lander may have just uncovered one of them before succumbing to a dust storm.
For years, scientists have debated whether Mars has a solid or liquid core. InSight attempted to find out by using its seismometer, SEIS, to search for evidence of a liquid core. Meanwhile, its RISE instrument measured tiny changes in the planet’s rotation caused by the gravitational pull of the Sun.
In a recent study published in Nature, the researchers behind the RISE instrument revealed their analysis of InSight’s radio tracking data. They argued against the existence of a solid inner core and provided insights into the shape of the core, suggesting the presence of internal mass anomalies deep within the mantle.
Unlocking the Mysteries of Mars
The RISE instrument works by transmitting radio signals to Earth and tracking changes in its location relative to our receivers. These changes, known as nutations, can reveal valuable information about Mars’ internal composition. However, detecting these changes based on radio signals proved challenging due to the planet’s noise and disturbances caused by dust storms and gravitational forces from its moons.
To make the RISE experiment successful, researchers needed to precisely determine InSight’s landing location on Mars. After processing the first RISE data, radio scientist Sebastien Le Maistre and his team uploaded a positional estimate to the Mars Reconnaissance Orbiter, which captured an image confirming InSight’s accurate landing.
Decoding the Nutations
With the knowledge of InSight’s exact location, the RISE instrument analyzed the nutations it detected to gain insights into Mars’ core. Retrograde nutations, indicating a wobbling axis moving counterclockwise, aligned with the hypothesis of a liquid core beneath a solid mantle. This alignment between the data and the hypothesis provided direct estimates of the properties of Mars’ core.
Further analysis suggested that Mars’ core is likely composed of a liquid iron and sulfur alloy, constantly undergoing convection. Unlike Earth’s core, which has a solid inner core, Mars’ core is believed to be entirely liquid. The scientists also speculated that Mars’ lower mantle might be molten, leading to subsurface mass anomalies that affect the planet’s surface and core.
As more RISE data becomes available, Le Maistre and his team hope to uncover additional insights about Mars’ anomalies and liquid core. The vast amount of data from InSight holds the potential to revolutionize our understanding of the Red Planet.
Nature, 2023. DOI: 10.1038/s41586-023-06150-0
Elizabeth Rayne is a creature who writes. Her work has appeared on SYFY WIRE, Space.com, Live Science, Grunge, Den of Geek, and Forbidden Futures. When not writing, she is either shapeshifting, drawing, or cosplaying as a character nobody has ever heard of. Follow her on Twitter @quothravenrayne.
NASA’s InSight mission, which was launched in 2018 to explore the interior of Mars, has revealed some interesting findings about the planet’s interior. In recent research presented at the 50th Lunar and Planetary Science Conference, scientists suggested that Mars has a liquid core and a peculiar interior.
The research was based on data collected by the InSight mission including the seismic activity of the planet, the variation of atmospheric temperature, and the slight wobbling movements of Mars’ rotation axis. Using this data, the research team was able to draw the conclusion that the core of Mars is liquid, which differs from Earth’s solid iron core.
The researchers also noted that the characteristics of the core suggested a “peculiar interior structure.” They explained that this structure appears to be much denser than it should be, which is likely because the iron core is more dense than expected, and that it is compressed by the planet’s own gravity. This is significant because it suggests that Mars is geologically active, even after billions of years since its formation.
In addition to the liquid core findings, the researchers reported that the data also revealed that the planet’s interior is composed of different layers of rock within a mantle and crust. The research team said that by better understanding the interior of Mars, it could provide valuable clues in unraveling how the planet formed and evolved over time.
The InSight mission is a major scientific milestone, and has been a success thus far. This latest research is just the beginning of unraveling the mysteries of Mars, and future missions and research projects are sure to shed more light on the history and evolution of the red planet.
