Why is Mars red? New research increases popular theory, say scientists, say

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With its legendary rusty color, Mars has long been referred to as Red Planet. Now scientists may have discovered the potential source of this distinctive color and tipped out a popular theory in this process.

Mars is one of the best examined planets in our solar system due to its proximity to the earth and the numerous spaceships that have visited in recent decades. Together, Orbiter and Lander scientists have provided data that show that the red color of Mars comes from rusted iron minerals within the dust that relates to the planet.

At some point, iron in rocks on Mars reacted with water or water and oxygen in the air and generate iron oxide – similar to how rust forms on earth. The iron oxide collapsed in dust for over billions of years and settled on the planet after being moved by Marswinden, the dust devil and massive dust storms.

Earlier analyzes of iron oxide on Mars, which were only based on observations by space vehicles, did not recognize any indications of water that the researchers believed that the iron oxide must be hematite. It was believed that the dry mineral, a main component of the iron ore, was formed over billiRes by reactions with the Mars atmosphere in a process. If this were the case, the hematite would later have formed in the history of Mars after being suspected of housing lakes and rivers on its surface.

New research work that combines data from several missions and replicated Mars dust has proposed a mineral that is responsible for the red color in the presence of cold water and not for hematite, which could change the way scientists could understand how Mars was millions of years ago. A team of scientists reported on Tuesday in the magazine Nature Communications.

“Mars is still the red planet,” said Adomas Valantinas, a post-doctorate from the Earth Department, Environmental and Planetary Sciences at Brown University. “It is only that our understanding of why the Mars is red has been changed.”

Scientists have been surprised at the exact composition of the iron oxide in the Mars dust, since the understanding, as it formed, enabled them to look back essentially in the time how the environment and the climate were on the old Mars.

Although dust covers everything on Mars, it is difficult to study and presents a mystery, said Briony Horgan, co-inventigator about the mission of Persevere Rover and professor of planetary science at Purdue University in West Lafayette, Indiana. Horgan was not involved in the study.

“The particles (of oxidized iron) are so small (nanometer or less) that they have no defined crystal structure and cannot be called real minerals,” said Horgan. “There are ways to form oxidized iron without water, and some proposed dry processes include surface oxidation such as the oxidation shells, which form in rocks in the antarctic dry valleys, and the surface oxidation by abrasion, since the surface is blown up with sand grains over long periods. But there are also many ways to oxidize with water, including in floors and lakes. ”

The new analysis indicates a different type of iron oxide that contains water that contains ferrihydrite called Ferrihydrit that quickly forms in cold water – and probably forms on Mars if water can still be present on the surface before the planet became colder and inhospitable. Ferrihydrit proposed earlier studies as a possible cause of the redness of Mars, but the new study has combined laboratory methods for the first time with observation data to provide evidence.

“This paper tries to find out which specific poorly poorly crystalline iron oxide could be responsible for the red component of the Mars dust, which would be helpful to train because this could help us determine which process creates the dust and when this happened,” said Horgan.

Valantinas and his team used data that were collected by the Mars Express Orbiter of the European Space Agency and the Exomars Trace Gas Orbiter as well as the Mars Reconnaissance Orbiter of NASA and curiosity, Pathfinder and Opportunity Rovers.

The Cassis Color Color of the Trace Gas Orbiter, also known as the color and stereo interface image system system, unveiled the exact size and composition of dust particles on Mars, so that the researchers could produce their own version on earth.

The scientists created their own Mars dust in a laboratory with different types of iron oxide. The replica dust was led by a specialized mill to create grains that the size on Mars with a thickness of 1/100. correspond to human hair.

The team analyzed the dust with X -ray machines and reflection spectrometers, similar to the techniques that examine Mars from Orbiter that examine Mars. The scientists then compared the laboratory data with spatial vehicle data.

The Mars Express-Omega reflection spectrometer showed that even the most dusty parts of Mars have information on water-rich minerals, while data from Cassis on the presence of Ferrihydrit as the best match with dust on Mars pointed out instead of hematite compared to the laboratory samples, according to Valantinas.

The instrument has been watching Mars since April 2018 and records high -resolution color images of the Marsian surface, said Nicolas Thomas, professor at the Physics Institute of the University of Bern in Switzerland, which was directed by the team that developed the camera.

“We found that Ferrihydrit with basalt, a volcanic rock, fits the minerals best seen by space vehicles on Mars,” said Valantinas, who started his research at the University of Bern with the data of the trace gas orbitors. “The greatest implication is that Mars had thought earlier than before because Ferrihydrit had only formed if there was still water. In addition, the ferrihydrite remains stable on Mars under today’s conditions. ”

The secret of Mars’s red color has been in existence for thousands of years, said Valantinas.

The Romans called Mars for their god of war because its color was reminiscent of blood and Egyptians called the planet “Your Desher”, which, according to the European space authority, means “the red”.

When he found that the color of the Mars was due to a water -containing rusty mineral such as Ferrihydrit, in contrast to Hämatitis rustform, the researchers surprised, said Valantinas. But it provides fascinating references to Mars’s geological and climatic history, he said.

“Since this water -containing rust covers most of the surface of the Marso, it indicates that liquid water in the old past of Mars may have been widespread than previously assumed,” said Valantinas. “This indicates that Mars once had an environment in which liquid water was present, which is an essential prerequisite for life. Our study shows that the formation of ferrihydrit on Mars is the presence of both the oxygen – be it from the atmosphere or other sources – as well as water that can react with iron. ”

The study did not focus on determining when exactly the mineral formed. However, since Ferrihydrite forms in cold water, it is possible that it was created about 3 billion years ago, in contrast to the time when the planet was warmer and millions of years ago.

“This was a time of intensive volcanic activity on Mars, which probably triggered ice reporting events and interactions between water and rock and provided favorable conditions for the formation of Ferrihydrit,” said Valantinas. “The timing corresponds to a time when Mars passed from its earlier moist state to its current desert environment.”

It is possible that Ferrihydrit is not only in dust, but also in layers of Marsfelsen. And the best way to say is to get actual rehearsals of rocks and dust from the red planet. The endurance Rover has already collected several samples, both of which contain, and NASA and ESA hope to use a complex series of missions as part of the Mars rehearsal return program to return them to earth until the early 2030s.

“As soon as we get these precious rehearsals into the laboratory, we can measure exactly how much ferrihydrit the dust contains and what this means for our understanding of the history of water – and the possibility for life – on Mars,” said Colin Wilson, Esa’s trace gas orbiter and Mars Express projector.

In the meantime, the results offer new secrets that Valantinas and his colleagues can solve, including the original source of Ferrihydrite, before it was distributed over dust over dust worldwide, and the exact chemical composition of the Mars atmosphere when the Ferrihydrite formed.

Understanding when and where the dust has formed can help scientists to gain insights into the development of the atmospheres of the early earth -like planets, said Horgan.

“Ferrihydrite is in floors on earth that moves a lot of water in a short time, in soils on earth, either because of the meltdown of snow or short times of intensive rainfall in warmer climate zones,” said Horgan. “We have also seen evidence of Ferrihydrit in the Lake sediments at the Stormkrater (Mars’) (which is examined by the Curiosity Rover). The best way to really solve this puzzle would be to bring a sample from Mars dust back into our laboratories on earth. ”