A virtual tour of the Galilean Satellites

Galileo's imagination was quick to comprehend the importance of the 4 starry objects he observed near Jupiter in January 1610, not only for himself as a scientist but for our common understanding of the place of the Earth and our species in the cosmos. Even he, however, could not have imagined what those four objects would actually look like once humans got their first good look. Some 369 years the fast traveling Voyager 1 and 2 spacecraft provided that first good look during 1979, followed by an even closer look from the Galileo Orbiter beginning in 1996 through 2001. The following mosaics represent some of the best of those views. They include views of impact craters young and ancient, icy terrains that have been intensely faulted, eroded or disrupted, mountains towering 10 or more kilometers high, and volcanic eruptions hotter than those on Earth. Each of the four Galilean satellites is geologically distinct, betraying very diverse global histories and evolutions. Images and other observations of these 4 objects revealed the importance of tidal heating and subsurface water oceans in planetary evolution, but mapping is very incomplete. New missions to explore these planetary bodies are being planned and the images and observations of the missions that went before will lay the groundwork for these new explorations as we begin the 5th Galilean century.

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Experimental access to Volcanic Eruptions and their role in the Earth System.

10.5194/egusphere-egu21-16014 ◽

2021 ◽

Author(s):

Donald B. Dingwell

Keyword(s):

Volcanic Eruptions ◽

Explosive Volcanism ◽

Hazard Mapping ◽

Earth System ◽

Planetary Evolution ◽

The Earth ◽

Experimental Approaches ◽

Impact Experiments ◽

Near Future

<p>Few things are more central to earth history, planetary evolution and the earth system, than volcanism. Explosive volcanism in particular exhibits individual events whose impact can range from local to global. Developing a mechanistic understanding of the inner workings of volcanic systems is essential for understanding their behavior and modelling their impact. Experiments form a fundamental part of our modern scientific approach to volcanic research, an approach which relies heavily on materials characterisation. In the year 2021, we can look back on decades of&#160; novel and highly innovative experimental approaches applied to the investigation of volcanic processes. The focus has ranged from pre-eruptive and eruptive dynamics&#160; all the way to the fate&#160; and importance of volcanic materials in the Earth System. The applied aspects of the work reach, for example, into eruption forecasting, hazard mapping and aviation safety. I will attempt portray the the long term strategy of the approach we have taken as well as providing comments on the likelihood of certain further developments in the near future.</p>

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Quantum Genetic Terrain Algorithm (Q-GTA): A Technique to Study the Evolution of the Earth Using Quantum Genetic Algorithm

Proceedings ◽

10.3390/ecea-5-06685 ◽

2019 ◽

Vol 46 (1) ◽

pp. 26

Author(s):

Pranjal Sharma ◽

Ankit Agarwal ◽

Bhawna Chaudhary

Keyword(s):

Genetic Algorithm ◽

Isotopic Fractionation ◽

Volcanic Eruptions ◽

Temperature Characteristic ◽

Isotopic Ratios ◽

Mantle Lithosphere ◽

Monitoring Networks ◽

Temperature Changes ◽

Quantum Genetic Algorithm ◽

The Earth

In recent years, geologists have put in a lot of effort trying to study the evolution of Earth using different techniques studying rocks, gases, and water at different channels like mantle, lithosphere, and atmosphere. Some of the methods include estimation of heat flux between the atmosphere and sea ice, modeling global temperature changes, and groundwater monitoring networks. That being said, algorithms involving the study of Earth’s evolution have been a debated topic for decades. In addition, there is distinct research on the mantle, lithosphere, and atmosphere using isotopic fractionation, which this paper will take into consideration to form genes at the former stage. This factor of isotopic fractionation could be molded in QGA to study the Earth’s evolution. We combined these factors because the gases containing these isotopes move from mantle to lithosphere or atmosphere through gaps or volcanic eruptions contributing to it. We are likely to use the Rb/Sr and Sm/Nd ratios to study the evolution of these channels. This paper, in general, provides the idea of gathering some information about temperature changes by using isotopic ratios as chromosomes, in QGA the chromosomes depict the characteristic of a generation. Here these ratios depict the temperature characteristic and other steps of QGA would be molded to study these ratios in the form of temperature changes, which would further signify the evolution of Earth based on the study that temperature changes with the change in isotopic ratios. This paper will collect these distinct studies and embed them into an upgraded quantum genetic algorithm called Quantum Genetic Terrain Algorithm or Quantum GTA.

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Accuracy Analysis of Gravity Field Changes from Grace RL06 and RL05 Data Compared to in Situ Gravimetric Measurements in the Context of Choosing Optimal Filtering Type

Artificial Satellites ◽

10.2478/arsa-2020-0008 ◽

2020 ◽

Vol 55 (3) ◽

pp. 100-117

Author(s):

Viktor Szabó ◽

Dorota Marjańska

Keyword(s):

Gravity Field ◽

Ocean Circulation ◽

Gravity Data ◽

The Other ◽

Subsurface Water ◽

Satellite Gravity ◽

Absolute Gravimetry ◽

The Earth ◽

Gravity Measurements ◽

Gravity Recovery

AbstractGlobal satellite gravity measurements provide unique information regarding gravity field distribution and its variability on the Earth. The main cause of gravity changes is the mass transportation within the Earth, appearing as, e.g. dynamic fluctuations in hydrology, glaciology, oceanology, meteorology and the lithosphere. This phenomenon has become more comprehensible thanks to the dedicated gravimetric missions such as Gravity Recovery and Climate Experiment (GRACE), Challenging Minisatellite Payload (CHAMP) and Gravity Field and Steady-State Ocean Circulation Explorer (GOCE). From among these missions, GRACE seems to be the most dominating source of gravity data, sharing a unique set of observations from over 15 years. The results of this experiment are often of interest to geodesists and geophysicists due to its high compatibility with the other methods of gravity measurements, especially absolute gravimetry. Direct validation of gravity field solutions is crucial as it can provide conclusions concerning forecasts of subsurface water changes. The aim of this work is to present the issue of selection of filtration parameters for monthly gravity field solutions in RL06 and RL05 releases and then to compare them to a time series of absolute gravimetric data conducted in quasi-monthly measurements in Astro-Geodetic Observatory in Józefosław (Poland). The other purpose of this study is to estimate the accuracy of GRACE temporal solutions in comparison with absolute terrestrial gravimetry data and making an attempt to indicate the significance of differences between solutions using various types of filtration (DDK, Gaussian) from selected research centres.

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The Early Earth: An Ocean with Volcanoes

Assembling Life ◽

10.1093/oso/9780190646387.003.0006 ◽

2019 ◽

Author(s):

David W. Deamer

Keyword(s):

Graduate Student ◽

North Pole ◽

Equal Probability ◽

Early Earth ◽

Planetary Evolution ◽

The North ◽

Tectonic Processes ◽

The Earth ◽

Life On Mars ◽

Geophysical Processes

Malcolm Walter was talking about the Pilbara region of Western Australia where some of the oldest known biosignatures of ancient life, in the form of extensive fossilized stromatolites, are preserved. The first potential stromatolite was discovered by graduate student John Dunlop, who was studying barite deposits at the North Pole Dome. Roger Buick went on to investigate the biogenicity of the stromatolites for his PhD (Buick, 1985) and Dunlop, Buick, and Walter published their results (Walter et al., 1980). In a prescient paper, Walter and Des Marais (1993) proposed that the ancient stromatolite fossils could guide the search for life on Mars. I have walked with Malcolm Walter through the Dresser formation where the fossils were found. It is humbling to realize that if time passed at a thousand years per second, it would take 41 days to go back in time to the first signs of life on our planet. In any description of events that occurred some 4 billion years ago, certain assumptions must be made. I will try to make assumptions explicit throughout this book, beginning here with the geochemical and geophysical conditions prevailing on the early Earth and Mars. I am including Mars not as an afterthought but because both planets had liquid water 4 billion years ago. Most of our understanding of planetary evolution comes from observations of our own planet, but it is now clear that the Earth and Mars were undergoing similar geophysical processes during the first billion years of the solar system’s existence, with an equal probability that life could begin on either planet. In a sense, the surface of Mars is a geological fossil that has preserved evidence of what was happening there at the same time that life began on the Earth. For instance, Martian volcanoes offer direct, observable evidence that volcanism was occurring nearly 4 billion years ago; making it plausible that similar volcanism was common on Earth even though the evidence has been completely erased by geological and tectonic processes.

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Scaling properties of planetary calderas and terrestrial volcanic eruptions

Nonlinear Processes in Geophysics ◽

10.5194/npg-19-585-2012 ◽

2012 ◽

Vol 19 (6) ◽

pp. 585-593 ◽

Cited By ~ 2

Author(s):

L. Sanchez ◽

R. Shcherbakov

Keyword(s):

Solar System ◽

Scaling Law ◽

Geographical Location ◽

Internal Heat ◽

Volcanic Eruptions ◽

Scaling Analysis ◽

Scaling Properties ◽

Caldera Formation ◽

Planetary Bodies ◽

Terrestrial Planetary Bodies

Abstract. Volcanism plays an important role in transporting internal heat of planetary bodies to their surface. Therefore, volcanoes are a manifestation of the planet's past and present internal dynamics. Volcanic eruptions as well as caldera forming processes are the direct manifestation of complex interactions between the rising magma and the surrounding host rock in the crust of terrestrial planetary bodies. Attempts have been made to compare volcanic landforms throughout the solar system. Different stochastic models have been proposed to describe the temporal sequences of eruptions on individual or groups of volcanoes. However, comprehensive understanding of the physical mechanisms responsible for volcano formation and eruption and more specifically caldera formation remains elusive. In this work, we propose a scaling law to quantify the distribution of caldera sizes on Earth, Mars, Venus, and Io, as well as the distribution of calderas on Earth depending on their surrounding crustal properties. We also apply the same scaling analysis to the distribution of interevent times between eruptions for volcanoes that have the largest eruptive history as well as groups of volcanoes on Earth. We find that when rescaled with their respective sample averages, the distributions considered show a similar functional form. This result implies that similar processes are responsible for caldera formation throughout the solar system and for different crustal settings on Earth. This result emphasizes the importance of comparative planetology to understand planetary volcanism. Similarly, the processes responsible for volcanic eruptions are independent of the type of volcanism or geographical location.

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D/H ratios of the inner Solar System

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2015.0390 ◽

2017 ◽

Vol 375 (2094) ◽

pp. 20150390 ◽

Cited By ~ 18

Author(s):

L. J. Hallis

Keyword(s):

Solar System ◽

Giant Planet ◽

Published Data ◽

Solar System Formation ◽

Atmospheric Processes ◽

The Past ◽

The Earth ◽

Planetary Bodies ◽

Original Water

The original hydrogen isotope (D/H) ratios of different planetary bodies may indicate where each body formed in the Solar System. However, geological and atmospheric processes can alter these ratios through time. Over the past few decades, D/H ratios in meteorites from Vesta and Mars, as well as from S- and C-type asteroids, have been measured. The aim of this article is to bring together all previously published data from these bodies, as well as the Earth, in order to determine the original D/H ratio for each of these inner Solar System planetary bodies. Once all secondary processes have been stripped away, the inner Solar System appears to be relatively homogeneous in terms of water D/H, with the original water D/H ratios of Vesta, Mars, the Earth, and S- and C-type asteroids all falling between δD values of −100‰ and −590‰. This homogeneity is in accord with the ‘Grand tack’ model of Solar System formation, where giant planet migration causes the S- and C-type asteroids to be mixed within 1 AU to eventually form the terrestrial planets. This article is part of the themed issue ‘The origin, history and role of water in the evolution of the inner Solar System’.

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Fluctuations in Secular Variation of the Rotation of the Earth and Volcanic Eruptions

Proceedings of the Imperial Academy ◽

10.2183/pjab1912.9.35 ◽

1933 ◽

Vol 9 (2) ◽

pp. 35-38 ◽

Cited By ~ 1

Author(s):

Hantaro NAGAOKA

Keyword(s):

Secular Variation ◽

Volcanic Eruptions ◽

The Earth ◽

Rotation Of The Earth

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Creasy and Wu Receive 2019 Study of the Earth’s Deep Interior Section Award for Graduate Research

Eos ◽

10.1029/2020eo149314 ◽

2020 ◽

Vol 101 ◽

Author(s):

Keyword(s):

San Francisco ◽

Fall Meeting ◽

Theoretical Approaches ◽

The Earth ◽

Graduate Research ◽

Deep Interior ◽

Planetary Bodies

Neala Marie Creasy and Wenbo Wu received the 2019 Study of the Earth’s Deep Interior Section Award for Graduate Research at AGU’s Fall Meeting 2019, held 9–13 December in San Francisco, Calif. The award is given annually for advances that contribute to “the understanding of the deep interior of the Earth or other planetary bodies using a broad range of observational, experimental, or theoretical approaches.”

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