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. 

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.

Review Lecture: The dynamical properties and internal structures of the Earth, the Moon and the planets

1972 ◽  
Vol 328 (1574) ◽  
pp. 301-336 ◽  
Keyword(s):  
Internal Structure ◽  
Recent Progress ◽  
High Pressures ◽  
Artificial Satellites ◽  
The Moon ◽  
The Earth ◽  
Internal Structures ◽  
Theoretical Investigations ◽  
Dynamical Properties ◽  
Very High

The aim of this review is to bring together and relate recent progress in three subjects - the internal structure of the Earth, the behaviour of materials at very high pressures and the dynamical properties of the planets. Knowledge of the internal structure of the Earth has been advanced in recent years, particularly by observations of free oscillations of the whole Earth excited by the very largest earthquakes; as a consequence, it is clear that K. E. Bullen’s hypothesis that bulk modulus is a smooth function of pressure irrespective of composition is close to the truth for the Earth. Understanding of the behaviour of materials at very high pressure has increased as a result both of experiments on the propagation of shock waves and of theoretical investigations along a number of lines and it can now be seen that Bullen’s hypothesis is not true irrespective of chemical composition and crystal structure but that it happens to apply to the Earth because of particular circumstances. Studies of the orbits of artificial satellites and space probes have led to better knowledge of the dynamics of the Moon, Mars and Venus, and there have also been recent improvements in the traditional studies of Uranus and Neptune. Our knowledge of the dynamics of the planets is on the whole rather restricted, and Bullen’s hypothesis only applies directly to the Moon (for which the application is trivial) and possibly to Mars; the dynamical properties do none the less set fairly restrictive limits to the models that can be constructed for other planets. It would be possible for all planets to have cores of similar composition to the Earth ’s, surrounded by mantles of different sorts, silicates for the terrestrial planets and mostly hydrogen for Jupiter, Saturn, Uranus and Neptune.

scholarly journals Hestia: The Indo-European Goddess of the Cosmic Central Fire

2019 ◽  
Vol 23 (1) ◽  
pp. 3-19
Author(s):  
Marcello De Martino
Keyword(s):  
The Moon ◽  
European Language ◽  
The Earth ◽  
Unique Model ◽  
Celestial Bodies ◽  
Astronomical Theory ◽  
Ancient Times ◽  
To Come ◽  
Atmospheric Phenomena ◽  
The Universe

The Pythagorean Philolaus of Croton (470-390 BCE) created a unique model of the Universe and he placed at its centre a ‘fire’, around which the spheres of the Earth, the Counter-Earth, the five planets, the Sun, the Moon and the outermost sphere of fixed stars, also viewed as fire but of an ‘aethereal’ kind, were revolving. This system has been considered as a step towards the heliocentric model of Aristarchus of Samos (310-230 BCE), the astronomical theory opposed to the geocentric system, which already was the communis opinio at that time and would be so for many centuries to come: but is that really so? In fact, comparing the Greek data with those of other ancient peoples of Indo-European language, it can be assumed that the ‘pyrocentric’ system is the last embodiment of a theological tradition going back to ancient times: Hestia, the central fire, was the descendant of an Indo-European goddess of Hearth placed at the centre of the religious and mythological view of a deified Cosmos where the gods were essentially personifications of atmospheric phenomena and of celestial bodies.

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>

scholarly journals On the Interaction Between Tectonic Processes of the Earth and the Moon

1972 ◽  
Vol 47 ◽  
pp. 220-225
Author(s):  
N. A. Kozyrev
Keyword(s):  
Causal Relation ◽  
Direct Interaction ◽  
Tectonic Activity ◽  
Irreversible Processes ◽  
The Moon ◽  
Tidal Forces ◽  
Tectonic Processes ◽  
The Earth ◽  
History Of ◽  
Celestial Bodies

At present seismographs are operating on the Moon as well, installed there owing to the successful Apollo missions. However these data are insufficient for detailed statistic investigations. That is why in case of the Moon we are to use indirect indications of its activity, such as the data on transient light phenomena from the catalogues by Miss B. Middlehurst. Among the great number of earthquakes there were chosen only the strong earthquakes (magnitude 6.5) with focuses deeper than 70 km. According to these characteristics 630 earthquakes were selected from 1904 to 1967. In the Middlehurst catalogue during the same period about 370 transient events on the Moon are registrated. A distribution of lunar events on the days of an anomalistic month gives evidence of the influence of the Earth's tidal forces (the Middlehurst effect). It appears that the distribution of earthquakes gives a similar curve. Thus the tidal interaction of the Earth and the Moon establishes certain synchronism in tectonic activity of these planets. The further statistic analysis reveals some more causal relation between the processes of the Earth and the Moon. Strongly pronounced maximum of lunar events is observed with the interval of 2–3 days after the earthquakes and the maximum of earthquakes – with quite the same interval after the lunar events. The peaks of these maxima exceed the mean number of events by a factor 3. The Moon Earth system is the astronomical example of a direct interaction of the processes in the neighbouring celestial bodies.The corresponding experiments, made at the Pulkovo Observatory, confirm the possibility of immediate interactions of irreversible processes due to the change of physical properties of time. Thus we can form a chronology of orogenesis on the Moon judging from the data on the history of the Earth. Tectonic processes of the Earth and the Moon seem to be in such a close interaction as if the Moon were in direct contact with the Earth, i.e. in other words, were its seventh continent. These conclusions give evidence of the extreme importance of regular seismic observations on the Moon.

scholarly journals LUNA AND MARS TERRAFORMING: FUNDAMENTAL PRINCIPLES

2021 ◽  
pp. 24-35
Author(s):  
V.V. VOROBIOV ◽  
О.S. SHYLO
Keyword(s):  
Environmental Factors ◽  
Active Phase ◽  
Material Base ◽  
The Moon ◽  
The Earth ◽  
Celestial Bodies ◽  
Methodological Approaches ◽  
Negative Factors

Formulation of the problem. Terraforming projects for other planets and celestial bodies of the solarsystem, primarily the Moon and Mars, can be developed on the basis of different methodological approaches. Whateverthe size of the settlements on the Moon and Mars might be or however many people may stay or live there, whatevermission they will carry out, whatever materials the lunar and Martian settlement bases can be made of, all these projectsshould deal with the set of individual negative, in relation to the settlers from the Earth, factors inherent in either of theplanets, which will definitely affect the formation of terraformist settlements. The purpose of the article is to considerthe role of hazardous environmental factors for settlers on the Moon and Mars in the context of architectural and urbanplanning features of settlements, show how these features can affect the formation of settlements for colonists from theEarth, and identify what a morphograph of a network of those settlements might look like after its terraforming has beencompleted. Conclusion. All the member countries of the “space club”, located on different continents, have alreadyentered an active phase of their projects aimed at developing the Moon and Mars surfaces. However, neither theprojects for settlements on these planets nor the approaches to the formation of the material base of the colonies, whichwill take into account all the inherent negative factors on the surfaces of these celestial bodies, have been extensivelydeveloped yet. The opinions of experts on this matter differ, and therefore it becomes possible to study this problemmore thoroughly in the context of developing settlements for earthlings, taking into account the negative influences ofthe environment on these celestial bodies.

scholarly journals A View to Anorthosites

2021 ◽  
Author(s):  
Homayoon Mohammadiha
Keyword(s):  
Plate Tectonics ◽  
Early Time ◽  
The Moon ◽  
Planetary Evolution ◽  
Planetary Geology ◽  
Lunar Science ◽  
The Earth ◽  
Celestial Bodies ◽  
The Subject ◽  
Impact Hypothesis

It seems anorthosites are by far interested by geologists because they give us great information about Earth history and how it was evolved in planetary geology. Planetary geology is subject the geology of the celestial bodies such as the planets and their moons, asteroids, comets, and meteorites. It is nearly abundant in the moon. So, it seems studying of these rocks give us good information about planetary evolution and the own early time conditions. Anorthosites can be divided into few types on earth such as: Archean-age (between 4,000 to 2,500 million years ago) anorthosites, Proterozoic (2.5 billion years ago) anorthosite (also known as massif or massif-type anorthosite) – the most abundant type of anorthosite on Earth, Anorthosite xenoliths in other rocks (often granites, kimberlites, or basalts). Furthermore, Lunar anorthosites constitute the light-colored areas of the Moon’s surface and have been the subject of much research. According to the Giant-impact hypothesis the moon and earth were both originated from ejecta of a collision between the proto-Earth and a Mars-sized planetesimal, approximately 4.5 billion years ago. The geology of the Moon (lunar science) is different from Earth. The Moon has a lower gravity and it got cooled faster due to its small size. Also, it has no plate tectonics and due to lack of a true atmosphere it has no erosion and weathering alike the earth. However, Eric A.K. Middlemost believed the astrogeology will help petrologist to make better petrogenic models to understand the magma changing process despite some terms geological differences among the Earth and other extraterrestrial bodies like the Moon. So, it seems that these future studies will clarify new facts about planet formation in planetary and earth, too.

Structure of the terrain and gravitational field of the planets: Kaula’s rule as a consequence of the probability laws by A.N. Kolmogorov and his school

2019 ◽  
Vol 485 (4) ◽  
pp. 493-496
Author(s):  
E. B. Gledzer ◽  
G. S. Golitsyn
Keyword(s):  
Random Walk ◽  
Gravitational Field ◽  
Spherical Harmonics ◽  
Empirical Data ◽  
The Moon ◽  
Linear Coefficient ◽  
Water Flows ◽  
The Earth ◽  
Order Of Magnitude ◽  
Celestial Bodies

Kaula’s empirical rule has been known for more than 50 years: the coefficients of expansion over spherical harmonics for the fluctuations of the gravitational field and terrain of the planets decrease as the number of the harmonic squared. This was found for Venus, the Moon, Mars, the asteroid Vesta, and very small celestial bodies. The inverse-square line spectra were also found for various types of the Earth’s surface on a scale of up to a hundred kilometers. From this it follows that the spectra of the terrain slope angles are constant, i.e., “white noise”. This, they are delta-correlated horizontally. These are the assumptions under which the random walk laws were derived by A.N. Kolmogorov in 1934. Using them, the equation of the horizontal probability diffusion of the terrain with the linear coefficient diffusion D is derived. Based on the empirical data, D = 1.3 ± 0.3 m for the Earth, while for Venus it is almost an order of magnitude less. The slopes resist the wind; the rock crumbles, and the water flows down the slopes as well. This consideration turns Kaula’s rule into the random walk laws (over terrain) developed by Kolmogorov in 1934.

Anaximander's Rings

1988 ◽  
Vol 38 (1) ◽  
pp. 49-51 ◽  
Author(s):  
István M. Bodnár
Keyword(s):  
Compressed Air ◽  
The Sun ◽  
The Moon ◽  
The Earth ◽  
Celestial Bodies

Anaximander is the first philosopher whose theory of the heavens is preserved in broad outlines. According to the sources the celestial bodies are huge rings of compressed air around the earth, each visible only where it is perforated by a tubular vent through which the fire contained in it can shine. Greatest and farthest of them is the sun, next comes the moon and under them there is the ring (or possibly rings) of the stars. It is a common practice to put and answer the following questions:(i) ‘…why he should have placed the stellar circles or rings closer to the earth than are the sun and the moon.’(ii) ‘…why these lower rings of stellar ρ do not obscure the brighter but more distant bodies.’

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