Investigation of Mars Seismic Attenuation Using InSight SEIS Data.

2020 ◽  
Author(s):  
Taichi Kawamura ◽  
Ludovic Margerin ◽  
Mélanie Drilleau ◽  
Sabrina Ménina ◽  
Philippe Lognonné ◽  
...  
Keyword(s):  
Water Content ◽  
Thermal State ◽  
Seismic Attenuation ◽  
Depth Range ◽  
The Moon ◽  
Martian Surface ◽  
Broadband Seismometer ◽  
The Earth ◽  
Seismic Coda ◽  
Seismic Quality Factor

<p> NASA InSight (the Interior Exploration using Geodesy and Heat Transport) has placed the first broadband seismometer (SEIS) on the Martian surface and now continuously monitoring Martian seismic activity. Since the first detection of a marsquake in March 2019, SEIS detected more than 200 marsquakes and Mars has been revealed to be a seismically active planet. The dataset can now be used to perform the seismic investigation of the Mars interior and interpret this in a comparative manner by referring to the examples from the Earth and the Moon.</p><p>In this study, we investigate the seismic attenuation on Mars and compare this with the Earth and the Moon. Attenuation can be described as a combination of inelastic absorption and elastic diffusion of energy. Such properties will give important constraints on the composition of the Mars interior and also its thermal state. Another interesting aspect will be to discuss the water content with respect to the attenuation. Given the large variety of water content for the Earth, the Moon and Mars, the attenuation feature will be likely to differ significantly between these planets and satellite. Here we use the seismic dataset obtained by InSight SEIS and construct a 1D structure of seismic attenuation on Mars. Then we refer to the values obtained for the Earth and the Moon to discuss the possible implication on their differences and similarities.</p><p>　The presentation aims to summarize the results from different approaches taken by the authors. The approach includes; 1) spectral analyses of seismic signals and spectral decay fitting, 2) seismic coda analyses with coda rise time and decay, 3) numerical coda simulation with diffusion theory on seismic energy. With these approaches we will be constraining seismic quality factor Q and diffusivity D for different depth range. Different approaches have sensitivities to different depth and prarameters and we aim to provide our view on the martian attenuation and diffusion to date by summarizing the obtained results.</p>

VI. The nature of the Moon’s surface - The lunar surface and the U. S. Ranger programme

1967 ◽  
Vol 296 (1446) ◽  
pp. 399-417 ◽  
Keyword(s):  
The Moon ◽  
Martian Surface ◽  
Mountain Ranges ◽  
The Earth ◽  
Time Dependencies ◽  
The Alps ◽  
Mare Serenitatis ◽  
The Impact ◽  
Characteristic Colour ◽  
Lunar Maria

The unaided eye can see roundish dark spots on the Moon set in a brighter back­ground. Telescopic observation of these dark spots, called maria (plural of mare , sea) reveals that they are nearly level terrain sparsely covered with craters. The brighter surroundings or terrae are from shadow measurements found to be higher, some 1 to 3 km above the maria. The terra elevations scatter widely, reaching several kilometres in the mountain ranges. The most prominent of these ranges occur as peripheral mountain chains around the near-circular maria. Examples are the Apennines, the Alps, the Carpathians, and the Altai Scarp. These arcuate chains surround the maria as the crater walls surround crater floors, an analogy that can be carried further and implies, apart from scale, a similar origin. This origin is almost certainly impact by massive objects. In the case of the impact maria and pre-mare craters, the source of the objects appear to have been a satellite ring around the Earth through which the Moon swept very early in its history, in its outward journey from its position of origin very near the Earth (Kuiper 1954, 1965). The post-mare craters are presumably mostly asteroidal (and partly comet­ary) in origin and related to the craters observed by Mariner IV on Mars. The estimated time dependencies of these two crater-forming processes are shown schematically in figure 1. A fuller discussion of this problem has been given else­where (Kuiper, Strom & Poole 1966; Kuiper 1966). The higher asteroidal impact rate on Mars, by a factor of about 15, as derived from the Mariner IV records, is interpreted as being due to the greater proximity to the asteroid ring. The num­erical factor approximately agrees with theory. Mars apparently lacks the equiva­lent of the initial excessively intense bombardment of the Moon (attributed to impacts by circumterrestrial bodies); unless, of course, the entire Martian surface has been molten and is directly comparable to the lunar maria. This does not seem probable but can at present not be ruled out; if true, the earliest surface history would have been erased. The nature of the mare surface has, during the past decade, been an object of much, perhaps too much, speculation. With the several recent successful lunar reconnaissance missions completed, the older interpretation of the maria as lava beds, based on telescopic observation, has been abundantly confirmed. Four options discussed in recent literature are analysed in Kuiper (1965, §§A, B, pp. 12–39). Among the most potent arguments for the lava cover of the maria are the prominent lava flows observed on Mare Imbrium and Mare Serenitatis, each having a characteristic colour. A map of some Mare Imbrium flows is found in figure 2.

scholarly journals Είμαστε μόνοι στο συμπάν; Οι μετεωρίτες δίνουν απαντήσεις;

2016 ◽  
Vol 47 (1) ◽  
pp. 32
Author(s):  
Ι. Μπαζιώτης ◽  
L. A. Taylor
Keyword(s):  
High Pressures ◽  
Geochemical Data ◽  
The Moon ◽  
Martian Surface ◽  
The Earth ◽  
Past Life ◽  
Celestial Bodies ◽  
Meteorite Fall ◽  
Event Based ◽  
Moon Landing

The humankind, despite the recent technological achievements, does not yet have the ability to carry out routine trips to nearby celestial bodies. However, space science is a reality. The “Apollo” missions, that took place during the period 1969-1972, included the moon landing, the walk of astronauts and collection of valuable samples. Since then, no similar space journey has been carried out. The possibility for future missions such as the return to the Moon or Mars, or to an asteroid (e.g., Vesta), seems small enough to be implemented in the next decades. Nevertheless, nature has the mechanism and procedures to resolve this problem by sending extra-terrestrial rocks in earth in the form of meteorites. Meteorite fall on Earth is a major event, as it reveals important information about the primordial stages of formation of our solar system, or the creation processes of other planets. However, the big question still remains; whether these rocks host or have traces of past life in turn employs researchers in the last twenty years. McKay et al. (1996) studied the meteorite ALH 84001 originating from Mars, claimed for important discoveries such as structures corresponding to nanobacteria. In the current paper, we focus on the origin of Martian meteorites, presenting their complete geological history; from the genesis of their protoliths till their falling to the earth. We attempt to shade light in the understanding of meteorite formation using mineralogical-petrological-geochemical data, and the assignment of timing for each event based upon contemporary geochronological data. Recently, studies of the Martian meteorite Tissint, allegedly discovered structures rich in carbon and oxygen. Furthermore, recent field observations from Curiosity rover, indicates the existence of surface water that flowed once in the past at the Martian surface. We conclude that the planet Mars might not be a "dead" planet. But it turns out that many of the meteorites that reach the Earth, have undergone a complex history which is associated with the development of very high pressures and temperatures on the surface of the planet (e.g., Mars) from which they originate, able to destroy any trace of life before them. After all, we should be very sceptic and evaluate all the possibilities before the acceptance for the existence of life out there. 

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

Probable Structure and Nature of the Formations on the Reverse Side of the Moon According to Photometric Measurements of Lunar Photographs

1962 ◽  
Vol 14 ◽  
pp. 39-44
Author(s):  
A. V. Markov
Keyword(s):  
The Moon ◽  
Probable Structure ◽  
The Earth ◽  
Interplanetary Station ◽  
Photometric Measurements ◽  
Automatic Interplanetary Station

Notwithstanding the fact that a number of defects and distortions, introduced in transmission of the images of the latter to the Earth, mar the negatives of the reverse side of the Moon, indirectly obtained on 7 October 1959 by the automatic interplanetary station (AIS), it was possible to use the photometric measurements of the secondary (terrestrial) positives of the reverse side of the Moon in the experiment of the first comparison of the characteristics of the surfaces of the visible and invisible hemispheres of the Moon.

scholarly journals Interpreting Locked Photographic Data: The Case of Apollo 17 Photo GPN-2000-00113

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
Pyrrhon Amathes ◽  
Paul Christodoulides
Keyword(s):  
Experimental Data ◽  
Computer Simulations ◽  
The Moon ◽  
Geometrical Analysis ◽  
Apparent Position ◽  
Apollo Program ◽  
The Earth ◽  
Novel Approach ◽  
The World ◽  
The Moment

Photography can be used for pleasure and art but can also be used in many disciplines of science, because it captures the details of the moment and can serve as a proving tool due to the information it preserves. During the period of the Apollo program (1969 to 1972), the National Aeronautics and Space Administration (NASA) successfully landed humans on the Moon and showed hundreds of photos to the world presenting the travel and landings. This paper uses computer simulations and geometry to examine the authenticity of one such photo, namely Apollo 17 photo GPN-2000-00113. In addition, a novel approach is employed by creating an experimental scene to illustrate details and provide measurements. The crucial factors on which the geometrical analysis relies are locked in the photograph and are: (a) the apparent position of the Earth relative to the illustrated flag and (b) the point to which the shadow of the astronaut taking the photo reaches, in relation to the flagpole. The analysis and experimental data show geometrical and time mismatches, proving that the photo is a composite.

scholarly journals Isotopic evidence for the formation of the Moon in a canonical giant impact

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sune G. Nielsen ◽  
David V. Bekaert ◽  
Maureen Auro
Keyword(s):  
Solar System ◽  
Isotope Fractionation ◽  
Main Stage ◽  
The Moon ◽  
Giant Impact ◽  
Bulk Silicate Earth ◽  
The Earth ◽  
The Standard Model ◽  
Isotopic Measurements ◽  
Origin Of The Moon

AbstractIsotopic measurements of lunar and terrestrial rocks have revealed that, unlike any other body in the solar system, the Moon is indistinguishable from the Earth for nearly every isotopic system. This observation, however, contradicts predictions by the standard model for the origin of the Moon, the canonical giant impact. Here we show that the vanadium isotopic composition of the Moon is offset from that of the bulk silicate Earth by 0.18 ± 0.04 parts per thousand towards the chondritic value. This offset most likely results from isotope fractionation on proto-Earth during the main stage of terrestrial core formation (pre-giant impact), followed by a canonical giant impact where ~80% of the Moon originates from the impactor of chondritic composition. Our data refute the possibility of post-giant impact equilibration between the Earth and Moon, and implies that the impactor and proto-Earth mainly accreted from a common isotopic reservoir in the inner solar system.

scholarly journals Life among the Craters

2004 ◽  
Vol 213 ◽  
pp. 199-202
Author(s):  
Harrison H. Schmitt
Keyword(s):  
Terrestrial Planets ◽  
The Moon ◽  
Detailed Understanding ◽  
The Earth ◽  
Planetary Mass ◽  
End Members

The Moon forms one end-member in the planetary mass series Earth-Venus-Mars-Mercury-Asteroids-Moon (Weissman 1999). Having a detailed understanding of the nature and evolution of the two end-members of this series, rather than of just the Earth, has increased the value of other data and inferences by orders of magnitude. As a consequence of obtaining an understanding of the evolution of a second planet, we now can look at other terrestrial planets with far greater insight than ever would have been possible otherwise (Fig. 1).

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