Mars is one of our closest neighbours in the Solar System, and for centuries, it inspired the imagination of humankind. Features such as impact craters and valleys, as well as dunes and polar ice caps fooled people into thinking that life might exist on the planet.
Today, however, Mars is a sterile frozen desert. But some evidence suggests that it once had a rich watery past with rivers, lakes and flood channels.
Mars is the fourth planet from the sun and has a thin, rarefied atmosphere made up of mostly carbon dioxide and traces of argon. The planet’s surface is covered with a thick layer of oxidized iron dust that gives it its ruddy appearance.
The Red Planet’s crust consists of volcanic basalt rock. This is the same type of rock that makes up the Earth’s oceans and the lunar maria. The crust is between 6 and 30 miles (10 and 50 kilometers) deep, according to NASA.
In a new study, researchers from the University of Iowa found that the crust of Mars is far more diverse than previously thought. This could help scientists understand how the Red Planet formed and may even shed light on our own planet’s history.
Scientists say the findings, which were published in Geophysical Research Letters on November 4, 2018, are important for understanding the evolution of Mars. The research also suggests that the planet’s crust may be divided into three separate layers.
Until now, the only way to gauge the thickness of Mars’ crust was through relative estimates that required assumptions about the planet’s structure. But now, seismology is providing independent measurements that allow scientists to measure the exact thickness of the crust across the entire planet.
This allows scientists to accurately map the thickness of the crust, which is essential for understanding its composition and evolution. The information can help explain how early differentiation processes shaped the solar system and why the crusts of Earth, Mars and other planets are different today.
Researchers from the University of Iowa discovered a strange concentration of silicon within the crust of Mars. This finding indicates that the planet’s crust was formed much earlier than previously thought, which helps scientists better understand how and when Mars first formed.
The mantle is the layer beneath the crust and core of a planet, where rocky material such as iron, nickel and silicates like olivine can be formed under extreme pressure. It is a crucial part of the planet’s internal structure and has an important role in geological processes such as tectonic activity and volcanic eruptions.
Scientists have been able to use seismic data from the InSight mission to get a better understanding of the interior structure of Mars, which until now was not fully known. These new findings are an exciting step forward in planetary seismology.
One of the key pieces of equipment used by InSight is a seismometer that measures the waves travelling through the planet’s internal structure after a quake. These waves can help reveal the size and make-up of a planet’s core and mantle, enabling scientists to calibrate its crustal thickness.
Another key instrument is a spectrometer that detects the elements present in the crust and mantle of a planet. This information provides important constraints on the composition of the different layers and helps to decipher how early differentiation processes evolved in the solar system.
During the course of InSight’s mission, researchers have also discovered evidence of a magnetic field that was once very active on Mars. This was caused by the presence of mantle plumes, large blobs of rock that rise from deep inside a planet and push through its middle layer to reach the base of its crust.
The team believes that this type of paleomagnetism is similar to the magnetic fields observed on Earth’s ocean floors. This suggests that Mars may have experienced plate tectonic activity some four billion years ago, but that the magnetic field has since faded away.
Mars’ core is a mystery, but it may be hiding an answer. Seismic waves from the planet’s recent “marsquakes” — named for the wavy sound they make inside it — hint at the thickness of its crust and its inner mantle, according to researchers. They sailed through the core’s interior and bounced off interfaces between different layers of rocks, says Brigitte Knapmeyer-Endrun, of the University of Cologne in Germany, who led the study.
The findings, published in Nature Astronomy on 27 October 2022, offer a new way to scan the planet’s interior. The technique uses a single instrument to measure the size and location of every region of the core, including its boundary, says co-author Hrvoje Tkalcic, an assistant professor at Australia’s National University (ANU) in Canberra, Australia.
This allows scientists to determine the planet’s composition and its overall chemistry, which is crucial for understanding why Mars is the only planet in our solar system without a magnetic field or active tectonic plate movement.
Scientists have suspected that Mars once had a magnetic field billions of years ago, but the red planet hasn’t shown any signs of turning on again. That might be because its core is so dormant, Stewart’s team suggests.
To find out, the team created a model of the core in the laboratory and compressed it to its maximum pressure. Then, they injected the mixture into a cylinder of diamond and let it cool down.
They then looked at the resulting seismological data to see how long it took the vibrations to travel from one point in the core to another. This is called the travel time curve, and it helps to determine whether the core has a liquid or solid outer layer.
The atmosphere of mars the planet made of is a thin, gaseous mix of water vapor, carbon dioxide, and other gases. It has low pressure and too little oxygen for life to develop. But it also provides important chemicals, and forms a visible sky from dispersed dust.
The average atmospheric temperature of Mars is 240degK at the ground, but is much lower at higher altitudes (around 190degK) because of the solar wind’s effects on air temperatures. At the surface, daytime temperatures are generally -163degC to -28degC, but drop to about -60degC at night.
There are many things that can affect the Martian atmosphere, such as thermal tides that can kick up fine dust. In addition, the boundary layer on Mars is more than 10 times higher than on Earth, a fact that is partly due to the thermal tides.
During the summer, the winds from these thermal tides can push fine dust into the lower atmosphere, raising its temperature. This is a major factor in the high levels of dust that form the Martian continents.
In winter, the deep cold southern polar winter removes carbon dioxide from the atmosphere by freezing it directly onto the south polar cap, causing air pressure to drop all over Mars. The pressure drops by about 25% to 30% on average across the whole planet.
Another thing that has an effect on the atmosphere of mars is the lack of a magnetosphere. Without one, the constant stream of particles from the sun can strip away atoms in the atmosphere, which reduces its density and makes it less stable. Scientists have been tracking this process with the MAVEN spacecraft, which has been observing the atmosphere since 2014.
Mars the planet made of rocks and dust
The surface of Mars is a complex mixture of rocks, minerals, and dust that reflect sunlight in different ways. From a distance the surface appears a variety of colors, including gold, tan, and brown, resulting from the oxidization of iron minerals in the rock and soil.
Earth-bound astronomers have long known that some areas of the Martian surface appear brighter than others, reflecting more of the sun’s light. Spectral analyses of the light reflected from Mars’ regolith (soil) and dust have revealed that these bright spots are rich in iron-bearing minerals, while dark patches contain unoxidized mineral materials.
These discoveries have led planetary scientists to conclude that the surface of Mars is mainly composed of two types of rocks: felsic and mafic. The northern lowlands are dominated by felsic rocks, while the ancient highlands of the southern hemisphere are mafic in composition.
This difference in rock composition has important implications for Mars’ climate and history. Mafic rocks are enriched in iron and magnesium, while felsic rocks are largely composed of silicates and olivine.
Moreover, since felsic rocks are more prone to erosion than mafic ones, the Martian surface has undergone more extensive weathering in the past. This weathering is probably responsible for the varying topography seen on the surface of Mars today, with valley networks and impact craters found in many regions of the planet.
The atmosphere of Mars is a complex mix of gases and air particles that can react rapidly to changes in solar radiation. The lower atmosphere is mostly carbon dioxide, which can reflect solar energy efficiently, and contains a large amount of suspended dust that absorbs heat from the Sun and distributes it throughout the atmosphere. This mixture creates a dynamic structure that can vary significantly from day to day.