Home Technology Unlocking the secrets of Mars: Scientists simulate geology and hydrology

Unlocking the secrets of Mars: Scientists simulate geology and hydrology

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Unlocking the secrets of Mars: Scientists simulate geology and hydrology

There are areas on the surface of Mars that are more than 3 billion years old
(photo: CC0 Public Domain)

Michael Allen

Mankind has probably been fascinated by Mars ever since its first representatives turned their eyes to the night sky. Space exploration today is a testament to this continuing fascination.

Since the 1960s, more than 40 missions have attempted to reach the Red Planet. As a result, today there are three rovers operating on the Martian surface, plus one lander and one helicopter, and eight artificial satellites orbiting the planet.

Special interest

“Many of the planets and moons in our solar system are interesting, but Mars is a little more special,” said François Forget, a scientist at the Sorbonne in France who studies the atmosphere. “Today, Mars and Earth are very similar, but in the past — 3 to 4 billion years ago — this similarity was even greater.”

And while we have a wealth of geological data thanks to the extensive research so far, much remains unknown about the fourth planet from the Sun.

There are signs that a vast ocean once covered the northern hemisphere of Mars, and elsewhere there are traces carved by rivers and glaciers.

And yet the climate processes that shaped the planet today remain a mystery.

4 billion years ago, when life began to emerge on Earth, there were rivers and lakes of water on Mars. Hence the possibility that life may have developed on Mars as well.

But scientists are also interested in the processes that created the dry desert planet we see today, and what they might reveal about Earth’s climate.

There are areas on the surface of Mars that are more than 3 billion years old. There are none on Earth, as it has been fundamentally altered by the living creatures that have largely erased the planet’s early history.

And something else makes Mars special — it’s a place astronauts hope to reach at some point.

The European Space Agency, or ESA, and the US National Aeronautics and Space Administration (NASA) are working on sending astronauts to Mars.

Test of time

Forge is the lead researcher on an EU-funded project developing a model of the evolution of Mars in an attempt to answer some of the questions about the history of the planet.

Called Mars in Time, the project began in late 2019 and is due to run until 2025.

According to Forge, current Martian climate models cover only short periods — a few years — of its history, and simulating the impact of features such as glaciers, rivers and lakes is complex, especially over long periods of time.

The project’s model is developed over thousands, even millions of years, simulating the past development of geological features along with the changing atmosphere.

And while models of current climate require hypotheses about the past location of water on the planet’s surface, the goal of the Martian evolution model is to find where water would have naturally formed and reached a stable equilibrium, Forge says.

This is achieved by including more data in the model, such as the effect of microclimatic conditions for example.

Pole-facing slopes of a planet, for example, tend to be colder, which can lead to the formation of ice and glaciers. Warmer slopes facing the equator are more likely to have water in liquid form.

“If you want to simulate the Earth, but you don’t know anything about it, you put water in the oceans, then the model of the evolution of the Earth will slowly create the Antarctic ice sheets, for example,” says Forge. “You want to do the same thing on Mars, and the model will of course create lakes, seas and rivers.”

It also includes large-scale changes that occur over longer geological periods. The tilt of Mars’ rotation axis typically changes every 50,000 years and causes large-scale climate changes.

Carbon dioxide glaciers

To use the model, scientists rely on known data from Mars’ past, such as the geology and topography, the location of rivers, lakes and glaciers, and the composition of the atmosphere. They also make some assumptions about the missing data.

As the simulation progresses, the scientists change their hypotheses and parameters until the evolution of the Mars model begins to match existing knowledge of the planet, past and present.

According to Forge, once a model is matched to geological data, it provides information about the planet’s environment, chemistry and atmosphere and how they have changed.

So far, the model has confirmed that some strange-looking moraines—debris left by glaciers—likely originate from glaciers of frozen carbon dioxide.

The simulations also suggest how these CO2 glaciers could have formed, and show that they led to dramatic changes in the composition of the Martian atmosphere.

To test one theory about the possible presence of water on the Martian surface, the scientists added a hydrogen-rich parameter to their model to understand how the Martian climate might have become warm enough to have liquid lakes and rivers.

The model shows that if Mars had a hydrogen-rich atmosphere in the past, it may have caused a significant greenhouse effect and increased the planet’s temperature.

Frozen reservoirs

At the other end of the temperature spectrum, a better understanding of how glaciers formed and where frozen water might exist today could help manned missions to Mars.

“According to NASA, it will be very useful to have access to ice from water without too much difficulty,” Forge said. “They set up project teams to look for where water ice might be found, and the Mars in Time project can really contribute to that.”

EU research could also provide information on where liquid water can be found. These are exactly the areas where astronauts would not want to land.

This is due to a concept known as “planetary protection”. The last thing astronauts would want to do is contaminate Mars with microorganisms from Earth, especially in water, which is a favorable environment for their growth.

This article was first published in Horizonthe EU research and innovation journal.

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