Series Of ‘Marsquakes’ Recorded By NASA Yields Most Complete Record Of Planet Formation Ever Detected

LONDON — For scientists hoping to piece together how rocky planets form, Earth is often the wrong place to look. Our planet possesses restless geology: shifting plates, erupting volcanoes, sinking ocean floors. It acts like a giant blender that churns and mixes material from deep within. Any record of Earth’s earliest days has long since been erased.

Mars, however, tells a different story. Unlike Earth, the Red Planet froze into a geological stillness billions of years ago. Now, new research published in Science reveals that Mars’ mantle, the thick layer of rock between crust and core, has preserved traces of its violent beginnings. The discovery was made possible by NASA’s InSight lander, which spent four years “listening” to “marsquakes” rippling through the planet’s interior.

Listening for Hidden Fragments

The study was led by a team from Imperial College London, working with colleagues in France, the U.S., and NASA’s Jet Propulsion Laboratory. They analyzed seismic waves from eight large marsquakes recorded between 2019 and 2022. Two of these were confirmed meteorite impacts, with craters identified by orbiting spacecraft, while the others were powerful natural quakes.

Some of these seismic waves traveled to depths of nearly 1,400 kilometers (about 870 miles) beneath the surface. As the waves passed through the mantle, they didn’t move smoothly. Instead, at higher frequencies they became distorted and delayed, like sound echoing through a cavern filled with uneven boulders.

That distortion provided the key clue: Mars’ mantle is far from uniform. Instead, it is littered with countless “heterogeneities” — kilometer-scale patches of rock with different compositions — scattered throughout. These chunks are between 1 and 4 kilometers in size (about 0.6 to 2.5 miles), and they appear everywhere seismic waves could probe.

A Chaotic Mantle Preserved

The way these heterogeneities are distributed follows what scientists call a fractal pattern. In simple terms, it means they appear across many size scales, like broken glass shattering into both big and tiny pieces. That kind of distribution points to extremely violent origins, such as the colossal impacts Mars endured during its infancy or the crystallization of a global magma ocean after those impacts.

Earth also experienced such processes, but its mantle has been thoroughly stirred over time. Mars, by contrast, seems to have locked its fragments in place. The researchers argue that this is because Mars’ interior convection — the slow rising and sinking of hot and cool rock — has been unusually sluggish for billions of years.

Using computer models, the team showed that only under specific conditions could such ancient structures survive. Mars’ mantle must be highly viscous, meaning it flows more like tar than water, and only weakly sensitive to changes in temperature. That combination would keep its interior moving so slowly that heterogeneities never blended away.

As the authors describe it Mars’ mantle has remained “highly disordered” but also remarkably well preserved. It is this disorder that has left the Red Planet with a fossil record of planetary formation that Earth cannot provide.

A Different Path From Earth

Planetary scientists describe Mars as a “single-plate planet.” Unlike Earth, which constantly recycles its crust through plate tectonics, Mars’ surface froze into what’s called a “stagnant lid.” This lid sealed off the mantle below and prevented the kind of vigorous mixing that erased Earth’s earliest history.

That actually makes Mars typical, not unusual. Stagnant-lid tectonics are thought to be the most common condition for rocky planets across the solar system. By studying Mars, scientists can glimpse how most rocky worlds evolve — and why Earth ended up on such a rare and active path.

The preserved mantle fragments also help solve a mystery that has puzzled researchers for decades: the diverse chemical fingerprints of Martian meteorites that land on Earth. The new study points out that mantle heterogeneities are consistent with achondritic meteorite compositions, which are rocks formed when Mars’ magma ocean crystallized and solidified. In other words, meteorites arriving on Earth may be sampling different preserved pockets of Mars’ interior, each with its own distinct chemistry.

Why It Matters

The discovery does more than explain Martian meteorites. It shows that Mars has been holding on to a hidden archive of solar system history for billions of years. These preserved fragments may capture information about the violent collisions, magma oceans, and chaotic processes that shaped not only Mars but also Earth, Venus, and countless rocky planets around other stars.

By revealing just how sluggish and viscous Mars’ mantle has been, the research also gives planetary scientists a new benchmark for understanding planetary evolution. It suggests that early heterogeneities can survive under stagnant-lid conditions, offering a possible roadmap for interpreting data from exoplanets or from future missions to other worlds.

All of this was made possible because of the InSight mission. Over four years, its seismometer recorded more than 1,300 marsquakes, but only eight events had the right strength and geometry to reveal the mantle’s secrets. Without InSight’s sensitive instruments, this picture of Mars’ preserved interior would have remained hidden.

Mars, it turns out, has been quietly archiving its own history while Earth erased much of its own. Thanks to InSight, scientists now have a clearer view of how the building blocks of planets were first assembled, and how those blocks have endured on our quiet, frozen neighbor.