Mars isn’t as frozen in time as it looks. The planet’s north pole is slowly sinking under the weight of an ice cap that only formed in the last few million years. That movement is giving scientists new insight into the Red Planet’s interior—thanks to data from landers we planted far from the pole.
WEIGHT OF THE WORLD
A planet’s crust might seem rock solid, but it bends and shifts over time. Earth’s ice ages saw massive glaciers pressing down the crust, which has been rising ever since those glaciers melted away—something called glacial isostatic rebound. Mars, being colder and further from the Sun, has its own version of this.
Mars’ polar ice caps seem ancient, but they’re surprisingly young. Orbital mechanics suggest the poles got more sunlight in the past. Climate models indicate the current caps are likely less than 10 million years old—just a blip in geological time.
SLOW-MOTION COLLAPSE
Because these ice caps are relatively new, the Martian crust beneath them is still sinking under their weight. That slow-motion collapse offers clues about the planet’s internal structure. But there’s a catch: this shift is happening too gradually to detect from orbit.
Instead of waiting around for visible surface changes, researchers turned to models. By plugging in different assumptions about Mars’ crust and mantle—things like thickness and heat levels—they created 84 possible scenarios. The challenge? Figuring out which of these actually match reality.
FINDING THE RIGHT FIT
To sort fact from fiction, researchers compared their models to actual Martian data, including readings from the InSight lander. This lander, positioned near the planet’s equator, measured seismic activity, giving scientists a peek at the planet’s inner workings. By combining this information with gravitational data and orbital tracking, they narrowed down the most accurate models.
The results suggest Mars’ interior is relatively warm, with a crust that behaves more like Earth’s than previously thought. That warmth means the crust at the north pole is still actively shifting under the ice cap’s pressure. Mars may not have plate tectonics like Earth, but its surface is anything but static.
Mars is still reshaping itself, even if it’s moving at a glacial pace.
Five Fast Facts
- Mars has the largest volcano in the solar system—Olympus Mons, which stands nearly three times taller than Mount Everest.
- The planet’s thin atmosphere means liquid water can’t exist on the surface for long—it either freezes or evaporates almost instantly.
- Mars’ gravity is only 38% of Earth’s, meaning a 200-pound person would weigh just 76 pounds there.
- The planet experiences dust storms so massive they can engulf the entire planet for weeks.
- Mars’ core is thought to be at least partially liquid, unlike the solid inner core of Earth.
