The international team of NASA’s InSight mission, using information obtained by the Very Broad Band SEIS seismometer detected many earthquakes on Mars, which is developed in France, has unveiled the internal structure of Mars. InSight is part of NASA’s Discovery Program. It is managed by the Mars Marshall Space Flight Center in Huntsville, Alabama.
Mars is the 4th planet from the sun and the 2nd largest planet in the solar system. The reddish color of Mars is due to Iron Oxydide, which is there on its surface. The name Red Planet given to Mars comes from the Roman God of War and the terrestrial planet whose atmosphere is the thin atmosphere, and it has a metallic dance core overlaid by less dense materials. The core consists of nickel and iron with a small portion of sulfur. The iron sulfide core is twice as rich in light elements compared to Earth. The silicate mantle surrounds the core that forms many of the volcanic and tectonic features on the planet. The most abundant element in the Martian crusts is potassium, calcium, aluminum, magnesium, iron.
The main purpose of the Mars Exploration Program by NASA –
- The formation and early evolution of the planet.
- The history of climate processes and geological processes that have shaped this planet through time.
- What is the possibility of life on this planet?
- What is the similarity between the planet and Earth?
Partners include – CNES, DLR, IPGP, MPS, ETH Zurich, CBK, CAB.
Published On – On July 23, 2021, three papers were published in the journal Science.
Authors – It involves many co-authors from French laboratories and institutions, including the Université de Paris and the Institut de Physique du Globe de Paris, and supported in particular by the ANR (the French National Research Agency) CNES (the French space agency).
The estimation – The mission scientists 1st time estimated the size of Mar’s core, the structure of its mantle, and the thickness of its crust. All these were found out based on the analysis of seismic waves reflected and modified by interfaces in its interior. This is 1st ever seismic exploration of the internal structure of a terrestrial planet other than Earth. This will help in a better understanding of the formation and thermal evolution of the planet.
Previous data – The planet’s internal structure not much information was there before NASA’s InSight mission. The models were based on data collected by orbiting satellites on the analysis of Martian meteorites that fell to Earth. Based on topographical data and gravity alone, the thickness of the crust was estimated to be between 30 and 100 km. The Mar’s movement of density and inertia value recommended a core with a radius of 1,400 to 2,000 km. The detailed structure of the planet and the depth of the boundaries between the core, mantle, and crust were completely not known.
Previous finding by NASA’s InSight mission – InSight recorded over 450 marsquakes and related events. InSight also revealed that Frequent small quakes frequently shake mars, and at one point in time, they were happening every day. But in late June, the deductions stopped, and only five quakes were detected since September 2020. For these seismically blank periods scientists, the planets are responsible. Around June, Mars entered the windiest season of the Martian year. Two sets of body waves are there in all quakes, which are primary waves and secondary waves. As part of a third category, there are small waves at the top of the crust, called surface waves. It has also collected the most comprehensive weather data on the surface of Mars. NASA said Mars is seismically active.
Landing date of NASA’s InSight mission spacecraft – NASA’s InSight spacecraft touched down Nov. 26, 2018.
Details about NASA’s InSight mission research –
In 2019, on the surface of the Red Planet, with the successful deployment of the SEIS experiment, the mission scientist collected and analyzed seismic data over one Martian year. The mission scientist includes the 18 French co-authors affiliated with a wide range of French institutes and institutions, colleagues from ETH in Zurich, the Jet Propulsion Laboratory in Pasadena, the University of Cologne.
More than one station is usually required to simultaneously find out a structural model of the arrival time of the earthquake and its distance. On this planet, scientists have only one station, Insight. The seismic records were necessary to search for the characteristic features of waves that had interacted in many ways with this planet’s internal structures and identify and validate them. These new measurements, along with mineralogical and thermal modeling of the internal structure of Mars, have made it possible to overcome the limitation of having a single station.
Another difficulty with this plant is its low seismicity and the seismic noise generated by its atmosphere. According to Philippe Lognonné, a Professor at the University of Paris and the Principal Investigator for the SEIS instrument at IPGP, “But although Martian earthquakes have a relatively low magnitude, less than 3.5, the very high sensitivity of the VBB sensor combined with the very low noise at nightfall enabled us to make discoveries that, two years ago, we thought were only possible with earthquakes with a magnitude greater than 4.”
The data is processed every day by CNRS, IPGP, CNES and transferred to the carefully cleaned scientists of ambient noise. The seismic events daily were recorded by the international Mars Quake Service team. More than 600 have now been recorded, out of which relatively distant earthquakes caused 60.
As they travel through the crust by comparing the behavior of seismic waves before reaching the InSight station in the crust, many discontinuities were identified. All these sheds light on the stratification of the crust beneath.
Here is the list of discontinuities that were identified–
- The 1st observed at a depth of about 10 km marks the boundary between a highly altered structure resulting from fluid every long ago and a crust that is only slightly altered.
- The 2nd discontinuity is around 20 km down was found.
- The 3rd less pronounced one at around 35 km was found.
According to Benoit Tauzin, Senior Lecturer at the University of Lyon and a researcher at LGL-TPE, “To identify these discontinuities, we used all the most recent analytical methods, both with earthquakes of tectonic origin and with vibrations caused by the environment (seismic noise).”
The scientist in the mantle analyzed the differences between the travel time of the waves during the earthquake produced directly and the waves generated when these direct waves were reflected off the surface. Using a single station, these differences made it possible to find out the structure of the upper mantle, and mainly with depth the variation in seismic velocities. But variation velocity is related to temperature. That means the heat flow of his plant can be estimated, which is mostly 3 to 5 times lower than Earth and on the composition of the Martian crust place constraints. Martian crust is thought to contain over half the heat-producing radioactive elements present on Mars.
In the 3rd study, the scientist looks for waves reflected off the surface of the Martian core. One of the main achievements of the mission is the measurement of that radius. Mélanie Drilleau, a research engineer at ISAE-SUPAERO, explains they have tested many thousand mantles and core models against the phrases and signals observed. With the reflected waves despite the low amplitudes of the signals associated, with a radius between 1 790 km and 1 870 km, an excess of energy was observed for cores. The large size indicates that the presence of light elements in the liquid core has at the core interference major consequences for the mineralogy of the mantle.