Mars’ Long Lost Moon Could Help Explain Its Extreme Terrain, Claims Study

Mars is unlike any other planet in our solar system due to its distinct ellipsoidal shape, having different sizes along all three axes. While it has two tiny moons today, the Red Planet might have once hosted a much larger moon, according to a theory proposed by Michael Efroimsky, an astronomer at the U.S. Naval Observatory in Washington, D.C. This moon, potentially named Nerio, may have played a significant role in shaping the planet's current topography, including its vast highlands and deep valleys.

Mars distinctive landscape

Mars is home to some of the most extreme features in the solar system, including the Tharsis bulge, a region about 5,000 kilometres wide and up to 7 kilometres high. On the opposite side of the planet lies Terra Sabaea, another highland area, along with Syrtis Major, a massive shield volcano.

These unique features could be remnants of Mars' ancient moon raising tides in the planet's magma oceans, much like how Earth's moon raises tides in our seas, according to a study published in the online journal arXiv.

The mystery of Nerio's disappearance

According to Efroimsky, the moon Nerio could have been destroyed by a collision or scattered out of the solar system due to gravitational interactions. While such events were common in the early solar system, no clear evidence, such as crater strings, points to this happening on Mars. It's possible geological activities may have erased any signs of Nerio's existence.

While the hypothesis remains speculative, it suggests that Mars' dramatic landscape could have been shaped by both Nerio and subsequent geological processes. Efroimsky encourages further research to explore the potential evidence for this lost moon and its impact on Mars' unique features.