Meteorites and Marsquakes Hint at an Underground Ocean of Liquid Water on the Red Planet

This isn’t just a game-changing discovery for planetary science—it could reshape our understanding of Mars' past, its climate, and whether life ever existed—or still exists—on the Red Planet.

Mars: A Dry World with a Watery Past

When you look at Mars through a telescope or in NASA’s high-resolution images, it appears dusty, rocky, and dry—more like a desert than a place that could support life. But that wasn’t always the case.

Scientists believe Mars once had a thick atmosphere, flowing rivers, lakes, and possibly vast oceans. Over time, much of its atmosphere was stripped away by solar winds, and the planet cooled, making the surface too cold and thin to support liquid water. Today, most of the water on Mars is locked up in polar ice caps or exists as vapor in the thin atmosphere.

So how can there still be liquid water?

That’s where things get interesting.

Meteorites Tell a Deeper Story

In recent years, Martian meteorites—chunks of Mars that were blasted into space and landed on Earth—have become treasure troves of information. These rocks have revealed chemical signatures and mineral structures that suggest they interacted with water underground before being ejected.

Minerals that were formed in the presence of liquid water are called hydrated minerals in some of these meteorites. More importantly, scientists discovered traces of salts and brines—chemical compounds that can keep water in a liquid state even at freezing temperatures. That means water could still exist in liquid form under the Martian surface if the right chemical mix is present.

But these are just clues—indirect evidence. What scientists really needed was something that could tell them what’s happening inside Mars right now.

Marsquakes: Listening to the Red Planet

Enter NASA’s InSight mission, a robotic lander that touched down on Mars in 2018. Its main goal? To study the internal structure of Mars, and more specifically, to listen for marsquakes—the Martian equivalent of earthquakes.

Unlike Earth, which has moving tectonic plates, Marsquakes are caused by the gradual cooling and contraction of the planet’s interior. These tremors send seismic waves through the crust and mantle, which InSight can detect using its ultra-sensitive seismometer.

Here’s where it gets exciting: some of these seismic waves didn’t behave the way scientists expected.

The Underground Ocean Clue

Seismic waves change speed and direction depending on the material they pass through. For example, they move differently through solid rock than they do through liquid water. When analyzing data from marsquakes, researchers noticed something unusual—the waves slowed down and refracted in a way that strongly suggests they passed through a liquid layer deep underground.

This layer is estimated to be located about 30 to 50 kilometers below the Martian surface, beneath the southern hemisphere's crust—and it could be a vast underground reservoir of salty, liquid water.

The water is likely extremely salty—more like a brine than freshwater—which would help it stay liquid even in the cold Martian interior. Even though it isn't as warm as a bathtub, it could support microbes similar to extremophiles that live in deep underground saltwater lakes and hydrothermal vents on Earth.

Mars vs. Europa and Enceladus

If this discovery holds up, Mars could join the ranks of ocean worlds in our solar system—planets or moons with subsurface oceans. This list already includes Jupiter’s moon Europa and Saturn’s moon Enceladus, both of which have icy surfaces with confirmed or suspected oceans underneath.

But Mars is different. Unlike those moons, which are coated in thick layers of ice, Mars’ crust is mostly rock. That could make any subsurface water on Mars more accessible to future missions, and more likely to have interacted with surface conditions in the past.

Could that be where life hides?

Let’s get to the question everyone’s thinking: Could something be living in that underground ocean?

The conditions are harsh—cold, salty, and lacking sunlight. But as we’ve seen on Earth, life can be incredibly resilient. In Antarctica, scientists have discovered entire ecosystems thriving in subglacial lakes beneath kilometers of ice. Microbes survive in deep underground rock layers, feeding on minerals and existing completely without sunlight.

If Mars has anything similar, it could harbor extremophile microbes, perhaps ancient organisms that have survived underground for billions of years. Even if life never evolved there, this underground ocean could contain organic compounds or chemical traces of past life—what scientists call biosignatures.

Why This Changes Everything

This discovery is about potential, not just curiosity. Here's why it matters:

Search for life: Liquid water is the most essential ingredient for life as we know it. Where there’s water, there could be life.

Future exploration: An underground ocean could be a future target for robotic drills or even human exploration. It could be a source of water for astronauts.

Understanding Mars’ history: The presence of long-term liquid water underground means Mars may have had habitable conditions for far longer than we thought.

Learning about Earth: Studying other planets teaches us more about our own. The interior of Mars may hold clues to the origins of Earth and the solar system.

The Next Steps: Digging Deeper

The current evidence is compelling, but not yet conclusive. Scientists need more data—especially direct samples. Future missions help with that. NASA’s upcoming Mars Sample Return mission aims to bring back rocks drilled by the Perseverance rover. If those rocks show similar signs of water interaction deep underground, it would be a huge confirmation.

There’s also interest in sending deep drilling missions—robotic landers equipped with high-powered drills that could bore down tens of kilometers. Though technologically challenging, such missions are already being conceptually designed.

Another idea? Deploying more sensitive seismometers across the Martian surface to triangulate marsquake data and create a 3D model of Mars' interior. Scientists would have a much clearer map of potential locations for liquid water thanks to this.

Public Fascination and the Human Angle

People are so excited about these kinds of discoveries because they make Mars seem less alien. An ocean beneath our feet—on another world—is the kind of thing that sounds like science fiction. And yet, it’s becoming science fact.

Social media platforms exploded with interest when this research was released. People drew comparisons to deep-sea mysteries, alien life, and even ancient Martian civilizations. While those are imaginative leaps, they reflect a genuine excitement: We are living in an era where the secrets of another planet are slowly being revealed.

Final Thoughts: A Watery World Beneath the Dust

Mars may look dry and lifeless from space, but underneath its rusty surface, it could be hiding something remarkable. Thanks to a combination of meteorites, marsquakes, and cutting-edge science, we’re closer than ever to proving that Mars has liquid water beneath its crust—perhaps even a vast underground ocean.

If confirmed, this discovery could rewrite everything we thought we knew about the Red Planet. It might turn out that Mars, far from being a dead world, is still geologically and possibly biologically alive.

In the not-so-distant future, human explorers may stand on the Martian surface, drill into its depths, and tap into this hidden ocean—bringing us one step closer to answering the age-old question: Are we alone in the universe?