Mars’ polar ice caps were one of the first terrestrial features discovered on Mars. Since the development of film in the 19th century, researchers have expected to see Earth-like activity such as the flow of polar ice. However, Mars does not meet expectations.

In 1971, data from Mariner 9 discovered south polar ice on Mars for the first time, sparking a 50-year debate over whether the ice flows. Whenever an interpretation of the flow emerged, it was quickly refuted by new observations.

For 50 years, researchers have been trying to explain this dormant ice. Now, a new paper led by Isaac Smith, a senior scientist at the Planetary Sciences Institute, has an answer: Ice composed of different layers of material can be held in place by those layers.

High-resolution images of Mars’ polar ice caps reveal complex layered structures. These caps are approximately 2–3 km (1.2–1.9 mi) thick and extend more than 1,000 km (600 mi) along the Martian poles. These caps are mostly made of water ice. Beneath the ice lies a complex landscape of steep slopes and cliffs.

Researchers expected ice flows in these regions could reach speeds of up to 1 meter per year, and even the most modest flow estimates predicted flows of 10 cm per year. This speed of movement was visible in fleeting images taken by modern missions, with their ability to recognize features as small as 1.2–2.4 m (4–8 ft). Long-term flow should also be visible in other features such as moraines (or rubble mounds), depressions in glacial rocks, and bed curvatures. None of these appear anywhere in the polar caps.

Given the lack of observations to support flowing ice, according to Smith, “The question then is: Why is the ice moving slower than predicted, and how much slower? We have an upper limit, so let’s test some hypotheses. In my paper, we’ll see if they can slow the ice down.” “I looked at four hypotheses for

In an article published in the journal IcarusIn his book “The Undetected Flow Hypothesis in Polar Layered Sediments of Mars,” Smith makes complex calculations for four different scenarios: 1) the ice is too cold to move, 2) impurities in the ice slow it down, 3) a homogeneous mixture is made of material that slows the flow, 4) the ice is layered in a way that uniquely slows the ice to an immeasurable flow.

Although all four ideas seemed possible, mathematical models showed that in the first three cases the ice would still have to move and leave tracks. Only in the final, multi-layered landscape model was the ice fixed in place.

“The layers are similar to how you make s’mores or Oreo cookies; hard layers with soft layers in the middle. If you stack enough Oreos on top of each other and press them down, they will be slightly runny, but not as much as if you did this. The Oreo mixture falls apart,” explains Smith. “The layer model can slow down by several orders of magnitude, enough to match the observed motions (or lack thereof).”

As we build models that allow us to understand the diversity of glaciers in our solar system, we begin to see that the physics may be the same everywhere, but certain local conditions cause things to behave very differently. It’s easy to think of Mars as Earth-like, and perhaps it once was, but for the last billion years Mars has had a unique, harsh climate that has allowed the study of non-Earth-like features.

“Researchers have been studying the polar caps of Mars since the time of Percival Lowell. Lowell even thought of flowing ice and canals to help people living on Mars,” Smith said, referring to Lowell’s work in the late 1800s and early 1900s. .

“To be able to say more about what is happening on other planets, we first need to understand basic physical principles. This is pretty esoteric. Few people understand the dynamics of ice sheets on other planets, but many more people are interested in the history of ice. Without the proper context on Mars, we could be misled for decades.

“Getting it right means knowing which processes are active and which are not. “I think this paper brings us one step closer to understanding why the ice on Mars seems to be not moving.”