A team of researchers led by Cypriot Planetary Scientist Dr. Constantinos Charalambous, has shed light for the first time on the fine structure of the mantle of planet Mars.
Dr Constantinos Charalambous, UK Space Agency Fellow in Mars Exploration Science, led a recent study as first author and member of NASA’s InSight science team, that was published in the Science Magazine. Dr Charalambous worked closely with seismologists and planetary scientists across Europe and the U.S. At Imperial College London, his team also contributed to the development of the short-period sensors onboard SEIS, the Seismic Experiment for Interior Structure, which enabled these precise, high-frequency measurements.
«InSight let us ‘hear’ seismic echoes from recent meteorite impacts reverberating through an ancient mosaic deep within Mars, revealing remnants of a story that began 4.5 billion years ago with colossal collisions. For the first time, we are seeing such fine-scale structure inside another planet – a kind of fossil record of Mars’ birth preserved in its grainy mantle – and this changes how we read the history of rocky worlds» Dr Charalambous told the Cyprus News Agency in an interview.
Mars, he added, offers the first direct evidence of fine-scale mantle heterogeneity in a rocky planet, opening a new window into planetary origins.
The way these internal structures are preserved links to thermal evolution, volcanism, gas release, and climate – ultimately, to what makes a world habitable, he told CNA.
It is recalled that in 2019, two rocks on planet Mars were named in the Cypriot dialect by NASA, in recognition of Dr Charalambous’ contributions to the InSight mission.
NASA gave Dr Charalambous the opportunity to name the rocks, and he honoured his birth roots by selecting the names ‘moutti’ (nose) and ‘zavos’ (askew, pointing at an angle) from the Cypriot dialect. The names were inspired by the distinct shapes and orientations of the rocks, which resembled their meanings.
‘This is the first time we have names in the Cypriot dialect on the red planet,’ Dr. Charalambous, had told CNA back then.
We ‘probed’ the deep interior of Mars
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Asked about his research, he said that ‘we probed’ the deep interior of Mars using NASA’s InSight seismometers – the only instrument ever to record quakes on another planet’.
‘We analysed eight distant marsquakes, including the two largest recent meteorite impacts observed, with the furthest occurring some 7,500 km away. By tracing how
seismic waves travelled through the mantle – the layer between the crust and the core – we essentially performed a kind of planetary ‘CT scan” he said.
Charalambous added that they observed that high-frequency waves systematically arrived delayed and ‘blurred’ compared to low-frequency ones.
‘This was a telltale sign that the waves scattered and slowed down as they travelled through the mantle, revealing a seismic path studded with obstacles – like sonar pings bouncing through a field of submerged boulders’.
Once they realised this, he said, the team set out to understand the origin and nature of these obstacles: how could such features form and persist inside a planet sealed beneath a stagnant lid for billions of years – unlike our Earth?
Main results of research
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‘The signal was clear: Mars’ mantle is not uniform, but ‘seeded’ with buried fragments up to kilometers in size, chaotically scattered down to ~1,400 km depth. For the first time, we are seeing such fine-scale internal structure preserved on a planetary scale – in any planet’ Charalambous told CNA.
These fragments, he noted, are ancient remnants of Mars’ violent beginnings: colossal impacts melted the early planet into magma oceans, which then crystallised into compositionally distinct ‘remnants’.
‘Mars, in this way, preserves a chaotic mosaic of its earliest formative stages’.
Those results are significant because the ‘remnants’ formed very early, from giant impacts and the crystallisation of magma oceans, leaving behind strong compositional heterogeneities, he said, adding that their distribution resembles ‘shattered glass’: a few large chunks, many smaller ones – a classic fingerprint of catastrophic, high-energy events.
Asked why they survived, he told CNA that Mars sealed its surface early with a stagnant crustal lid, adding that in contrast, Earth’s tectonic plates constantly recycle the lithosphere, injecting slabs into the mantle and stirring it vigorously – erasing most early signatures in the process.
‘The survival of these heterogeneities 4.5 billion years later tells us that Mars’ mantle was geologically near ‘static’ – highly viscous and poorly mixed. Its sluggish convection stretched and folded these fragments, like a baker kneading stiff dough, but never erased them. That, in turn, has major implications for the planet’s thermal evolution, and how it sheds heat from its core’.
In short, he went on to say, ‘we reveal a heterogeneous, ‘fractured’ mantle that preserved the scars of its planetary youth – because Mars churned slowly beneath a single, rigid lid’.
This stands in contrast to Earth’s dynamically active and recycling interior, which has erased most of its early structural and chemical signatures, and with them, the vital clues of our planet’s early history and evolution, Charalambous added.
First detailed, planet-wide look at Mars’ fine mantle structure
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Invited to refer to the significance of those findings for Mars, he said that ‘this is our first detailed, planet-wide look at its fine mantle structure’.
Mars, he pointed out, ‘acts as a time capsule. Unlike Earth, where tectonics and active convection erase most early signatures, Mars sealed itself early under a stagnant lid – preserving a secret journal of its violent formation and evolution’.
‘What we see – ancient, kilometer-scale remnants studded throughout the mantle – implies weak mixing over billions of years. This gives us the key to unlock Mars’ thermal history: a highly viscous, sluggish mantle cools slowly and inefficiently, shaping the way the planet evolved’.
But this ‘key’, he stressed, doesn’t just unlock Mars.
‘It tells us how the memory of planetary birth and evolution can be preserved in rocky worlds. Most rocky planets (and exoplanets) likely have stagnant lids, rather than plate tectonics like Earth. Understanding what happens inside them is crucial to figuring out which ones remain geologically active – and which might be potentially habitable’.
This, Charalambous said, directly connects to habitability over geological timescales: whether there’s long-lived volcanism, how gases and water cycle through the planet, how climate stays stable.
‘Not because Mars is globally habitable today, but because it can help us better understand the deep processes that make some rocky planets more hospitable than others’.
Earth has erased much of its own early record
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Invited to refer to the significance of those findings for Earth, he said that our planet has erased much of its own early record, noting that Mars gives us a reference point: it shows what survives in a world without tectonics, and helps us better interpret how – and why – Earth remained geologically ‘alive’.
He explained that when we say Earth is ‘alive,’ we mean tectonic activity, volcanism, and a churning mantle that constantly refreshes the planet’s surface and environment.
‘Studying Mars’ more primitive interior helps illuminate what makes that possible here’ he pointed out.
We hope it paves the way for a new generation of missions to Mars and beyond
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Charalambous said that it has been an honour to be part of the NASA InSight team -from mission design, testing and launch to data analysis – and to contribute to one of the mission’s final major discoveries.
‘Turning a single seismometer – when on Earth we rely on global networks – into a tool for planetary tomography was a challenging but exhilarating journey. We hope it paves the way for the next generation of missions to Mars and beyond’ he stressed.
In addition, he said that in that same spirit, he is also part of the NASA Farside Seismic Suite team where two seismometers will land on the Moon’s far side to record moonquakes and impacts.
‘As the new wave of lunar exploration gathers pace, those measurements-together with data from current and upcoming missions-will greatly deepen our understanding of our nearest neighbor’s interior and, by extension, shed light on Earth’s own history’ he concluded.