scholarly journals Interplanetary transmissions of life in an evolutionary context

2020 ◽  
Vol 19 (4) ◽  
pp. 335-348
Author(s):  
Ian von Hegner
Keyword(s):  
Solar System ◽  
Planetary Science ◽  
Evolutionary Strategy ◽  
Individual Risk ◽  
Bet Hedging ◽  
Bacterial Colony ◽  
Probability Of Survival ◽  
Crucial Difference ◽  
Evolutionary Response ◽  
Inverse Proportionality

AbstractThe theory of lithopanspermia proposes the natural exchange of organisms between solar system bodies through meteorites. The focus of this theory comprises three distinct stages: planetary ejection, interplanetary transit and planetary entry. However, it is debatable whether organisms transported within the ejecta can survive all three stages. If the conjecture is granted, that life can indeed be safely transmitted from one world to another, then it is not only a topic pertaining to planetary science but also biological sciences. Hence, these stages are only the first three factors of the equation. The other factors for successful lithopanspermia are the quality, quantity and evolutionary strategy of the transmitted organisms. When expanding into new environments, invading organisms often do not survive in the first attempt and usually require several attempts through propagule pressure to obtain a foothold. There is a crucial difference between this terrestrial situation and the one brought about by lithopanspermia. While invasive species on Earth repeatedly enters a new habitat, a species pragmatically arrives on another solar system body only once; thus, an all-or-nothing response will be in effect. The species must survive in the first attempt, which limits the probability of survival. In addition, evolution sets a boundary through the existence of an inverse proportionality between the exchanges of life between two worlds, thus further restricting the probability of survival. However, terrestrial populations often encounter unpredictable and variable environmental conditions, which in turn necessitates an evolutionary response. Thus, one evolutionary mode in particular, bet hedging, is the evolutionary strategy that best smooth out this inverse proportionality. This is achieved by generating diversity even among a colony of genetically identical organisms. This variability in individual risk-taking increases the probability of survival and allows organisms to colonize more diverse environments. The present analysis to understand conditions relevant to a bacterial colony arriving in a new planetary environment provides a bridge between the theory of bet hedging, invasive range expansion and planetary science.

PLANETARY SCIENCE: How Neptune Pushed the Boundaries of Our Solar System

Science ◽  
2004 ◽  
Vol 306 (5700) ◽  
pp. 1302-1304 ◽  
Author(s):  
A. Morbidelli
Keyword(s):  
Solar System ◽  
Planetary Science

Assembling aliens to explore the Solar System

2021 ◽  
Author(s):  
Catarina Leote ◽  
Sérgio Pereira ◽  
João Retrê ◽  
Pedro Machado ◽  
Gabriella Gilli ◽  
...  
Keyword(s):  
Solar System ◽  
Learning Strategies ◽  
Science Communication ◽  
Planetary Science ◽  
Lessons Learned ◽  
Board Game ◽  
Whole Process ◽  
Informal Educators ◽  
Low Exposure ◽  
Challenging Situation

<p><strong>Assembling aliens to explore the Solar System</strong></p> <p>After analysing the school curricula until 7th grade (13 years old), we concluded that, at least in Portugal, there is a limited coverage of astronomy subjects. This situation is also often accompanied by limited training of primary and medium school teachers and limited availability of resources in their mother tongues, as language can also be a barrier for the use of existing resources. In addition, some astronomy concepts require a level of abstract thinking that might be discouraging for some children. The end result is that some children will have a low interest in astronomy, not only because of their personal preferences but as a consequence of low exposure to the subject or a negative perception towards it. To address this situation, the Science Communication Group of Instituto de Astrofísica e Ciências do Espaço (IA) developed a board game about the Solar System, aimed at children from 6 to 12 years old, and adapted to both formal and informal educational contexts. This project, “Help your Alien – A Solar System Game”, was funded in 2019 by the Europlanet Society through its Public Engagement Funding Scheme.</p> <p><strong>Why a board game?</strong></p> <p>By opting for a board game instead of a digital platform, we made the conscious decision of valuing the power of storytelling and social interaction as engaging and focus-promoting learning strategies, unlike the information and stimuli overload sometimes present in digital environments. Another choice made to make the game as appealing and relatable to our target public as possible was to start with a more familiar perspective, biology, as children of this age group will certainly be familiar with “animals” and their characteristics. We made a leap forward towards astrobiology, and created imaginary aliens somehow adapted to their planets and moons. While trying to assemble these imaginary creatures, in a 3-piece puzzle, the game players have to gather information about different objects of the Solar System and discover the home planet of their assembled aliens.  Another reason for creating a board game was the possibility of reaching different publics, in particular those perhaps not immediately interested in astronomy. With “ET – A Solar System Adventure”, we hope to engage children but also their families (parents, grandparents, siblings…), just for the sake of playing, while exposing them to knowledge about the Solar System.</p> <p><strong>Development of the game</strong></p> <p>The game was developed in a collaborative creative process by members of the Science Communication Group and researchers in Planetary Sciences of the IA, combining knowledge in science communication and different publics with scientific knowledge. Even though the game mechanics was inspired in already existing and well-tested games, the whole process of creating this game involved many challenges, from defining the level of complexity while keeping the game engaging, to the adventure of “creating” aliens somehow physiologically adapted to different planets and moons of the Solar System. Mistakes were made and the team had to adapt to the unexpected challenging situation of a pandemic. This resulted in many lessons learned that we hope to share with the community. The game is now at its final stages of production, with the prototype being converted into a polished version with professional illustration and design. A “Print and Play” version in Portuguese and English will soon be made available online on our website. Physical copies will also be produced depending on funding.</p> <p>In our presentation, we will present our game, as well as the premises and goals behind it, its development process, the challenges found along the way, the lessons learned and some strategies to cope with the “new normality” imposed by Covid-19, while advancing the project. We hope the presentation of “ET – A Solar System Adventure” in the EPSC2021 will help to promote this tool for planetary science education among formal and informal educators and to find international collaborations for the translation and local promotion of the game, as well as additional funding for the production of physical copies in different languages.</p>

Gaia spectroscopic view of the asteroid main belt and beyond

2021 ◽  
Author(s):  
Marco Delbo ◽  
Laurent Galluccio ◽  
Francesca De Angeli ◽  
Paolo Tanga ◽  
Alberto Cellino ◽  
...  
Keyword(s):  
Solar System ◽  
Preliminary Investigation ◽  
Planetary Science ◽  
Reflectance Spectra ◽  
Physical Parameters ◽  
The Novel ◽  
Main Belt ◽  
Compositional Gradient ◽  
Solar System Object ◽  
Science Community

<div class="">Asteroids reflectance spectra in the visible light will be one of the novel products of the Gaia Data Release 3 (DR3). These spectra are produced from Gaia observations obtained by means of the blue and red photometers — the so-called BP and RP, respectively. We will review the strategy adopted to produce asteroid reflectance spectra from BP-RP data, focusing on the choice of spectro-photometric calibrations computed taking into account solar system object astrometry and suitable lists of solar-analog stars.</div> <div class=""> </div> <div class="">Our preliminary investigation shows that we will be able to obtain reflectance spectra for asteroids as small as some km in the main belt, by exploiting the fact that each object has been observed multiple times by Gaia. We will show the capability of Gaia to probe the detailed compositional gradient of the main belt down to small sizes and to study correlations between spectral classes and other asteroid physical parameters, such as albedo and size.</div> <div class=""> </div> <div class="">Concerning the brightest asteroids, we expect to have substantial signal at wavelengths shorter than 450 nm, allowing Gaia to examine this region of the spectrum that has been poorly investigated by ground-based asteroid spectroscopic surveys. This region is characterised by the presence of a reflectance downturn that is diagnostic for the composition of classes of primitive asteroids, for instance those including the parent bodies of carbonaceous chondrites. These asteroids may have played an important role for the delivery of prebiotic compounds to Earth during the early phases of solar system' s history and, as such, are at the center of attention of the planetary science community. </div>

Trans-Neptunian Dwarf Planets

2021 ◽  
Author(s):  
Bryan Holler
Keyword(s):  
Solar System ◽  
Surface Composition ◽  
Planetary Science ◽  
Chemical Diversity ◽  
Asteroid Belt ◽  
Dynamical Structure ◽  
Forthcoming Article ◽  
Cold Temperatures ◽  
Dwarf Planets ◽  
Physical And Chemical

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Planetary Science. Please check back later for the full article. The International Astronomical Union (IAU) officially recognizes five objects as dwarf planets: Ceres in the main asteroid belt between Mars and Jupiter; and Pluto, Eris, Haumea, and Makemake in the trans-Neptunian region beyond the orbit of Neptune. However, the definition used by the IAU applies to many other trans-Neptunian objects (TNOs) and can be summarized as any nonsatellite large enough to be rounded by its own gravity. Practically speaking, this means any nonsatellite with a diameter >400 km. In the trans-Neptunian region, there are more than 100 objects that satisfy this definition, based on published results and diameter estimates. The dynamical structure of the trans-Neptunian region records the migration history of the giant planets in the early days of the solar system. The semi-major axes, eccentricities, and orbital inclinations of TNOs across various dynamical classes provide constraints on different aspects of planetary migration. For many TNOs, the orbital parameters are all that is known about them, due to their large distances, small sizes, and low albedos. The TNO dwarf planets are a different story. These objects are large enough to be studied in more detail from ground- and space-based observatories. Imaging observations can be used to detect satellites and measure surface colors, while spectroscopy can be used to constrain surface composition. In this way, TNO dwarf planets not only help provide context for the dynamical evolution of the outer solar system, but also reveal the composition of the primordial solar nebula as well as the physical and chemical processes at work at very cold temperatures. The largest TNO dwarf planets, those officially recognized by the IAU, plus others such as Sedna, Quaoar, and Gonggong, are large enough to support volatile ices on their surfaces in the present day. These ices are able to exist as solids and gases on some TNOs, due to their sizes and surface temperatures (similar to water ice on Earth) and include N2 (nitrogen), CH4 (methane), and CO (carbon monoxide). A global atmosphere composed of these three species has been detected around Pluto, the largest TNO dwarf planet, with the possibility of local atmospheres or global atmospheres at perihelion for Eris and Makemake. The presence of nonvolatile species, such as H2O (water), NH3 (ammonia), and organics provide valuable information on objects that may be too small to retain volatile ices over the age of the solar system. In particular, large quantities of H2O mixed with NH3 points to ancient cryovolcanism caused by internal differentiation of ice from rock. Organic material, formed through radiation processing of surface ices such as CH4, records the radiation histories of these objects as well as providing clues to their primordial surface compositions. The dynamical, physical, and chemical diversity of the >100 TNO dwarf planets are key to understanding the formation of the solar system and subsequent evolution to its current state. Most of our knowledge comes from a small handful of objects, but we are continually expanding our horizons as additional objects are studied in more detail.

scholarly journals Factoring Origin of Life Hypotheses into the Search for Life in the Solar System and Beyond

Life ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 52 ◽  
Author(s):  
Alex Longo ◽  
Bruce Damer
Keyword(s):  
Solar System ◽  
Hydrothermal Vents ◽  
Hot Springs ◽  
Planetary Science ◽  
Icy Moons ◽  
Alternative Hypotheses ◽  
Biochemical Mechanisms ◽  
Early Mars ◽  
Life On Earth ◽  
Detection Strategies

Two widely-cited alternative hypotheses propose geological localities and biochemical mechanisms for life’s origins. The first states that chemical energy available in submarine hydrothermal vents supported the formation of organic compounds and initiated primitive metabolic pathways which became incorporated in the earliest cells; the second proposes that protocells self-assembled from exogenous and geothermally-delivered monomers in freshwater hot springs. These alternative hypotheses are relevant to the fossil record of early life on Earth, and can be factored into the search for life elsewhere in the Solar System. This review summarizes the evidence supporting and challenging these hypotheses, and considers their implications for the search for life on various habitable worlds. It will discuss the relative probability that life could have emerged in environments on early Mars, on the icy moons of Jupiter and Saturn, and also the degree to which prebiotic chemistry could have advanced on Titan. These environments will be compared to ancient and modern terrestrial analogs to assess their habitability and biopreservation potential. Origins of life approaches can guide the biosignature detection strategies of the next generation of planetary science missions, which could in turn advance one or both of the leading alternative abiogenesis hypotheses.

MOSCOW INTERNATIONAL SYMPOSIA ON SOLAR SYSTEM RESEARCH (10M-S3 AND 11M-S3) REPORTS REVIEW. Part 1. Mars exploration

2021 ◽  
pp. 114-136
Author(s):  
Roman A. EVDOKIMOV
Keyword(s):  
Solar System ◽  
Solar System Research ◽  
New Technologies ◽  
Interplanetary Space ◽  
Planetary Science ◽  
Subsurface Water ◽  
System Research ◽  
Deep Space ◽  
Wide Range ◽  
Scientific Results

A review of the reports of the last two Moscow International Symposia on Solar System Research has been completed. In the first part of the review, 43 reports of the main session of the "Mars" section are considered. The works of leading experts in the field of planetary science cover a wide range of scientific and applied problems - from the study of the geological history and climate of Mars, the search for traces of life and subsurface water reserves, to new technologies in planetary research, mission planning, as well as monitoring solar activity and radiation conditions in the interplanetary space, orbit and the surface of Mars. The data obtained in the last two decades has made it possible to significantly advance in understanding the nature of Mars, but many unresolved questions remain regarding the climate in the early era, the existence of the Martian oceans in the past, biological and geological activity. The scientific results obtained by unmanned spacecraft should be fully taken into account in the development of manned deep space exploration programs. Key words: Solar system, planetology, international symposium, deep space, automatic interplanetary stations, Mars, Moon, reports review

Epilogue: Paradigms, Problems, and Predictions

2017 ◽  
Author(s):  
John Chambers ◽  
Jacqueline Mitton
Keyword(s):  
Solar System ◽  
Planetary Systems ◽  
Planetary Science ◽  
Good Time ◽  
Science Program ◽  
The Galaxy ◽  
Recent Developments ◽  
Powerful Stimulus ◽  
Rapid Pace ◽  
Over Time

This concluding chapter talks about how astronomers and space agencies in dozens of countries are helping to see the solar system as never before, transforming points of light into real worlds, and even bringing samples of those worlds back to Earth. At the same time, the stunning discovery of hundreds of other planetary systems in the galaxy has provided a powerful stimulus to understand how planetary systems form and evolve, and to find out what makes one system different from another. Moreover, in 2010, NASA announced its latest science plan. One of the key goals for NASA's future planetary science program is to learn how the Sun's family began and how it has changed over time. The chapter argues that the rapid pace of recent developments makes now a good time to take stock of what scholars know, even though the story is still incomplete.

scholarly journals Modes of response to environmental change and the elusive empirical evidence for bet hedging

2011 ◽  
Vol 278 (1712) ◽  
pp. 1601-1609 ◽  
Author(s):  
Andrew M. Simons
Keyword(s):  
Environmental Change ◽  
Empirical Evidence ◽  
Natural Environments ◽  
Bet Hedging ◽  
Fluctuating Selection ◽  
Hedging Strategies ◽  
Evolutionary Response ◽  
Human Decision ◽  
Response To Environmental Change

Uncertainty is a problem not only in human decision-making, but is a prevalent quality of natural environments and thus requires evolutionary response. Unpredictable natural selection is expected to result in the evolution of bet-hedging strategies, which are adaptations to long-term fluctuating selection. Despite a recent surge of interest in bet hedging, its study remains mired in conceptual and practical difficulties, compounded by confusion over what constitutes evidence for its existence. Here, I attempt to resolve misunderstandings about bet hedging and its relationship with other modes of response to environmental change, identify the challenges inherent to its study and assess the state of existing empirical evidence. The variety and distribution of plausible bet-hedging traits found across 16 phyla in over 100 studies suggest their ubiquity. Thus, bet hedging should be considered a specific mode of response to environmental change. However, the distribution of bet-hedging studies across evidence categories—defined according to potential strength—is heavily skewed towards weaker categories, underscoring the need for direct appraisals of the adaptive significance of putative bet-hedging traits in nature.

scholarly journals Advances in Cosmochemistry Enabled by Antarctic Meteorites

2020 ◽  
Vol 48 (1) ◽  
pp. 233-258
Author(s):  
Meenakshi Wadhwa ◽  
Timothy J. McCoy ◽  
Devin L. Schrader
Keyword(s):  
Solar System ◽  
Planetary Science ◽  
The Moon ◽  
Origin And Evolution ◽  
Lunar Meteorite ◽  
Planetary Bodies ◽  
The Antarctic ◽  
Melt Pockets ◽  
Scientific Advances

At present, meteorites collected in Antarctica dominate the total number of the world's known meteorites. We focus here on the scientific advances in cosmochemistry and planetary science that have been enabled by access to, and investigations of, these Antarctic meteorites. A meteorite recovered during one of the earliest field seasons of systematic searches, Elephant Moraine (EET) A79001, was identified as having originated on Mars based on the composition of gases released from shock melt pockets in this rock. Subsequently, the first lunar meteorite, Allan Hills (ALH) 81005, was also recovered from the Antarctic. Since then, many more meteorites belonging to these two classes of planetary meteorites, as well as other previously rare or unknown classes of meteorites (particularly primitive chondrites and achondrites), have been recovered from Antarctica. Studies of these samples are providing unique insights into the origin and evolution of the Solar System and planetary bodies. ▪  Antarctic meteorites dominate the inventory of the world's known meteorites and provide access to new types of planetary and asteroidal materials. ▪  The first meteorites recognized to be of lunar and martian origin were collected from Antarctica and provided unique constraints on the evolution of the Moon and Mars. ▪  Previously rare or unknown classes of meteorites have been recovered from Antarctica and provide new insights into the origin and evolution of the Solar System.

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