Does topography matter for rocky exoplanets?

2020 ◽  
Author(s):  
Claire Marie Guimond ◽  
Oliver Shorttle ◽  
John F. Rudge
Keyword(s):  
Solar System ◽  
Building Materials ◽  
Silicate Weathering ◽  
Earth System ◽  
Dynamic Topography ◽  
Geologic Time ◽  
Scaling Relationships ◽  
The Earth ◽  
Crucial Component ◽  
Rocky Planets

<p>Topography is a crucial component of the Earth system: having rock exposed to the atmosphere lets surface temperatures self-regulate via silicate weathering, for example. However, there are limits to a lithosphere’s capacity to support mountains or valleys over geologic time. We see in our solar system that the range in a body’s elevations tends to decrease with increasing planet mass. These trends, inherent to planetary building materials, are modelled using well-studied concepts from geodynamics. As a first step, we predict feasible thermal evolutions and dynamic topography scaling relationships for rocky planets, eventually gearing to ask how massive a planet can be and still likely maintain subaerial land.</p>

scholarly journals Lunar exploration: opening a window into the history and evolution of the inner Solar System

2014 ◽  
Vol 372 (2024) ◽  
pp. 20130315 ◽  
Author(s):  
Ian A. Crawford ◽  
Katherine H. Joy
Keyword(s):  
Solar System ◽  
Lunar Exploration ◽  
The Moon ◽  
Moon System ◽  
Origin And Evolution ◽  
The Earth ◽  
Geological Evolution ◽  
History Of ◽  
Rocky Planets

The lunar geological record contains a rich archive of the history of the inner Solar System, including information relevant to understanding the origin and evolution of the Earth–Moon system, the geological evolution of rocky planets, and our local cosmic environment. This paper provides a brief review of lunar exploration to-date and describes how future exploration initiatives will further advance our understanding of the origin and evolution of the Moon, the Earth–Moon system and of the Solar System more generally. It is concluded that further advances will require the placing of new scientific instruments on, and the return of additional samples from, the lunar surface. Some of these scientific objectives can be achieved robotically, for example by in situ geochemical and geophysical measurements and through carefully targeted sample return missions. However, in the longer term, we argue that lunar science would greatly benefit from renewed human operations on the surface of the Moon, such as would be facilitated by implementing the recently proposed Global Exploration Roadmap.

New Heavens, New Earth

Dark Skies ◽  
2020 ◽  
pp. 65-104
Author(s):  
Daniel Deudney
Keyword(s):  
Solar System ◽  
Human Life ◽  
Earth System ◽  
Human Control ◽  
The Past ◽  
The Earth ◽  
Orbital Space ◽  
The Many ◽  
Life On Earth ◽  
Modern Astronomy

Humans have always attributed enormous importance to occurrences in the heavens. Over the past several centuries modern astronomy has revealed a cosmos of staggering size, filled with trillions of worlds. Its vacuum, weightlessness, lethal radiations, and fantastic speeds make space harshly inhospitable to human life. To access orbital space requires velocities some thirty-four times as fast as jet aircraft, climbing out of steep gravity wells. Of the many bodies mapped by science in this solar system, asteroids are most practically important because they sometimes collide with great violence, profoundly shaping Earth’s deep history. As knowledge of the cosmos has grown, anticipations of nearby intelligent life have dramatically shrunk. The Space Age has also witnessed a far-reaching revolution in understanding the Earth System. Marked by complexity, chaos, and emergence, life on Earth is incompletely understood and inventoried and much less subject to human control than previously assumed, reducing the feasibility of expansionist visions.

Superlinear scaling of riverine biogeochemical function with watershed size

2021 ◽  
Author(s):  
Wilfred Wollheim ◽  
Tamara Harms ◽  
Andrew Robison ◽  
Lauren Koenig ◽  
Ashley Helton ◽  
...  
Keyword(s):  
Allometric Scaling ◽  
Spatial Scales ◽  
River Networks ◽  
Power Exponent ◽  
Earth System ◽  
Network Function ◽  
Scaling Relationships ◽  
The Earth ◽  
Watershed Size

Abstract River networks are a crucial component of the earth system because they regulate carbon and nutrient exchange between continents, the atmosphere, and oceans. Quantifying the role of river networks at broad spatial scales must accommodate spatial heterogeneity, discharge variability, and upstream-downstream connectivity. Allometric scaling relationships of cumulative biogeochemical function with watershed size integrate these factors, providing an approach for understanding the role of fluvial networks in the earth system. Here we demonstrate that allometric scaling relationships of cumulative river network function are linear (power exponent ~ 1) when biogeochemical reactivity is high and river discharges are low, but become increasingly superlinear (power exponent > 1) as reactivity declines or discharge increases. Superlinear scaling indicates that biogeochemical function of entire river networks within a watershed is an emergent property that increases disproportionately with increasing watershed size. Expanding observation networks will increase precision in riverine fluxes of carbon and nutrients estimated by allometric scaling functions.

scholarly journals The exoplanet perspective on future ice giant exploration

2020 ◽  
Vol 378 (2187) ◽  
pp. 20200054 ◽  
Author(s):  
H. R. Wakeford ◽  
P. A. Dalba
Keyword(s):  
Solar System ◽  
Energy Budget ◽  
Giant Planet ◽  
Ground Truth ◽  
Molecular Absorption ◽  
Typical Size ◽  
Size Regime ◽  
The Earth ◽  
Habitable Zones ◽  
Rocky Planets

Exoplanets number in their thousands, and the number is ever increasing with the advent of new surveys and improved instrumentation. One of the most surprising things we have learnt from these discoveries is not that small-rocky planets in their stars habitable zones are likely to be common, but that the most typical size of exoplanets is that not seen in our solar system—radii between that of Neptune and the Earth dubbed mini-Neptunes and super-Earths. In fact, a transiting exoplanet is four times as likely to be in this size regime than that of any giant planet in our solar system. Investigations into the atmospheres of giant hydrogen/helium dominated exoplanets has pushed down to Neptune and mini-Neptune-sized worlds revealing molecular absorption from water, scattering and opacity from clouds, and measurements of atmospheric abundances. However, unlike measurements of Jupiter, or even Saturn sized worlds, the smaller giants lack a ground truth on what to expect or interpret from their measurements. How did these sized worlds form and evolve and was it different from their larger counterparts? What is their internal composition and how does that impact their atmosphere? What informs the energy budget of these distant worlds? In this we discuss what characteristics we can measure for exoplanets, and why a mission to the ice giants in our solar system is the logical next step for understanding exoplanets. This article is part of a discussion meeting issue ‘Future exploration of ice giant systems’.

Plate tectonics and Earth System Science

2021 ◽  
Author(s):  
Dietmar Müller
Keyword(s):  
Plate Tectonics ◽  
Plate Boundary ◽  
Plate Motion ◽  
Plate Boundaries ◽  
Earth System ◽  
Dynamic Topography ◽  
Lithospheric Deformation ◽  
The Earth ◽  
Plate Models ◽  
Reconstruction Software

<p>Over the last 25 years the theory of plate tectonics and a growing set of geo-databases have been used to develop global plate models with increasing sophistication, enabled by open-source plate reconstruction software, particularly GPlates. Today’s editable open-access community models include networks of evolving plate boundaries and deforming regions, reflecting the fact that tectonic plates are not always rigid. The theory of plate tectonics was originally developed primarily based on magnetic anomaly and fracture zone data from the ocean basins. As a consequence there has been a focus on applying plate tectonics to modelling the Jurassic to present-day evolution of the Earth based on the record of preserved seafloor, or only modelling the motions of continents at earlier times. Modern plate models are addressing this shortcoming with recently developed technologies built upon the pyGPlates python library, utilising evolving plate boundary topologies to reconstruct entirely destroyed seafloor for the entire Phanerozoic. Uncertainties in these reconstructions are large and can represented with end-member scenarios. These models are paving the way for a multitude of applications aimed at better understanding Earth system evolution, connecting surface processes with the Earth’s mantle via plate tectonics. These models allow us to address questions such as: What are the causes of major perturbations in the interplay between tectonic plate motion and Earth’s deep interior? How do lithospheric deformation, mantle convection driven dynamic topography and climate change together drive regional changes in erosion and sedimentation? How are major perturbations of the plate-mantle system connected to environmental change, biological extinctions and species radiation?</p>

scholarly journals On the Origin(s) and Evolution of Earth's Carbon

Elements ◽  
2019 ◽  
Vol 15 (5) ◽  
pp. 307-312 ◽  
Author(s):  
Sami Mikhail ◽  
Evelyn Füri
Keyword(s):  
Solar System ◽  
Carbon Isotope ◽  
Earth System ◽  
The Core ◽  
The Earth ◽  
Relative Abundances ◽  
Bulk Carbon

The isotopic “flavor” of Earth's major volatiles, including carbon, can be compared to the known reservoirs of volatiles in the solar system and so determine the source of Earth's carbon. This requires knowing Earth's bulk carbon isotope value, which is not straightforward to determine. During Earth's differentiation, carbon was partitioned into the core, mantle, crust, and atmosphere. Therefore, although carbon is omnipresent within the Earth system, scientists have yet to determine its distribution and relative abundances. This article addresses what we know of the processes involved in the formation of Earth's carbon reservoirs, and, by deduction, what we know about the possible origins of Earth's carbon.

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.

Preface: Evolution of the early solar system: Presolar cosmochemical fingerprints and the formation of watery rocky planets

2016 ◽  
Vol 50 (1) ◽  
pp. 1-2 ◽  
Author(s):  
Tomohiro Usui ◽  
Audrey Bouvier ◽  
Justin I. Simon ◽  
Noriko Kita
Keyword(s):  
Solar System ◽  
Early Solar System ◽  
Rocky Planets
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