Plate Nº 77 · recorded September 30, 2026
Space & AstronomyReported finding
Mars' North Pole Holds Far Less Dust Than Scientists Believed
A new analysis using Earth-tested methods finds Mars' north polar ice holds about 3% dust by mass, not 25% as previously estimated — with implications for climate history and habitability.
By Elena Vasquez3 min read638 words
In brief
- The new study estimates dust in Mars' north polar ice at ~3% by mass, down from earlier estimates of up to 25%.
- The revised calculations use methods developed by UW professor emeritus Steve Warren, long applied to snow and ice on Earth, instead of a lunar-soil model.
- The ice is layered 'like an ice cream sandwich': dusty winter frost sits atop older, cleaner ice exposed each summer.
The north pole of Mars is dramatically cleaner than scientists had assumed, according to a University of Washington study published in npj Space Exploration. Earlier estimates put the dust content of the top layer of polar ice at as much as 25% by mass. The new analysis brings that figure down to roughly 3%.
The finding matters because dust changes how ice behaves. Dark, dusty ice absorbs more sunlight, warms up, and vaporizes faster. "Just like a dark T-shirt in the sun makes you warmer, dusty ice gets warmer and vaporizes faster on Mars," said Aditya Khuller, a senior research scientist at the UW's Applied Physics Laboratory and one of the study's authors.
An Earth-tested method applied to Mars
The result stems from a methodological correction. Several years ago, Khuller noticed a problem with the standard technique researchers used to analyze the physical properties of Martian ice. That approach was originally developed for studying lunar soil, and when Khuller tested its accuracy on Earth, the results seemed off.
For the new study, Pari Mohan, a recent UW geoscience graduate, worked with Khuller to recalculate the ice's properties using a different framework. Their method builds on the work of Steve Warren, a UW professor emeritus of Earth and space science who has spent decades analyzing snow and ice on our own planet.
"His methods had been used successfully to study snow and ice on Earth for decades. So I thought it would be interesting to adapt these Earth-tested methods to Mars," Khuller said.
The team drew on data from NASA's Mars Phoenix mission, which sampled ice near the north pole in 2008, and combined it with observations from orbiting satellites. Phoenix was a milestone for NASA, arriving nearly a decade after the Polar Lander went missing near the south pole in 1999.
An ice cream sandwich structure
The analysis suggests the north polar ice is stacked "like an ice cream sandwich." Dustier layers sit between slabs of cleaner ice. Every Martian winter, a frost layer rich in dust forms on top; every summer, it disappears and exposes older, cleaner ice underneath.
"By looking at how the brightness changed over time, we figured out that there is a frost that forms in the winter and it's more dusty. In the Martian summer it goes away, exposing cleaner, older ice," Khuller explained.
These layers preserve a climate record stretching back thousands of years, to when the ice likely formed from snowfall. Mars undergoes massive ice ages that have deposited shallow ice across roughly one-third of the planet. Unlike Earth, which is stabilized by its large moon's gravitational pull, Mars has only two small moons and "oscillates wildly," as Khuller put it — a wobble that drives those dramatic climate swings.
A possible habitat for life?
The study also feeds into a bigger question. In earlier work, Khuller and colleagues proposed that dusty ice layers could create habitable conditions on Mars. Dark dust within ice can trap sunlight and melt pockets of water inside it, and those pockets, enriched with nutrients from the dust, could potentially host bacteria or other primitive life forms.
Analogous pockets of shallow, dusty meltwater on Earth teem with life in summer; in winter, the microbes go dormant and wait for the thaw.
"The fact that Mars and Earth both have these similar layers of water ice and dust is interesting," Khuller said. "Why does one planet have life and the other doesn't?"
Answering that question will likely take years. In the meantime, Khuller plans to apply the refined method to other regions of the red planet.
Reference: Mohan et al., "Revised dust content and grain size of exposed water ice at the North Pole of Mars," npj Space Exploration (2026). DOI: 10.1038/s44453-026-00054-9
via Phys.org Space & Astronomy (Source)
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