scholarly journals Biosignatures Search in Habitable Planets

Galaxies ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 82 ◽  
Author(s):  
Riccardo Claudi ◽  
Eleonora Alei
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
Planetary Atmospheres ◽  
General Interest ◽  
Habitable Planets ◽  
Planetary Bodies ◽  
The Right ◽  
Rocky Planets ◽  
The Universe

The search for life has had a new enthusiastic restart in the last two decades thanks to the large number of new worlds discovered. The about 4100 exoplanets found so far, show a large diversity of planets, from hot giants to rocky planets orbiting small and cold stars. Most of them are very different from those of the Solar System and one of the striking case is that of the super-Earths, rocky planets with masses ranging between 1 and 10 M ⊕ with dimensions up to twice those of Earth. In the right environment, these planets could be the cradle of alien life that could modify the chemical composition of their atmospheres. So, the search for life signatures requires as the first step the knowledge of planet atmospheres, the main objective of future exoplanetary space explorations. Indeed, the quest for the determination of the chemical composition of those planetary atmospheres rises also more general interest than that given by the mere directory of the atmospheric compounds. It opens out to the more general speculation on what such detection might tell us about the presence of life on those planets. As, for now, we have only one example of life in the universe, we are bound to study terrestrial organisms to assess possibilities of life on other planets and guide our search for possible extinct or extant life on other planetary bodies. In this review, we try to answer the three questions that also in this special search, mark the beginning of every research: what? where? how?

Earth's thermospheric evolution and implications for planetary habitability

2020 ◽  
Author(s):  
Colin Johnstone
Keyword(s):  
Carbon Dioxide ◽  
Solar Wind ◽  
Chemical Composition ◽  
Solar System ◽  
Planetary Atmospheres ◽  
Upper Atmosphere ◽  
The Sun ◽  
The Earth ◽  
First Time ◽  
Planetary Habitability

<p>During the Archean eon from 3.8 to 2.5 billion years ago, the Earth's upper atmosphere and interactions with the magnetosphere and the solar wind were likely significantly different to how it is today due to major differences in the chemical composition of the atmosphere and the younger Sun being signifcantly more active. Understanding these factors is important for understanding the evolution of planetary atmospheres within our solar system and beyond. While the higher activity of the Sun would have caused additional heating and expansion of the atmosphere, geochemical measurements show that carbon dioxide was far more abundant during this time and this would have led to significantly thermospheric cooling which would have protected the atmosphere from losses to space. I will present a study of the effects of the carbon dioxide composition and the Sun's activity evolution on the thermosphere and ionosphere of the Archean Earth, studying for the first time the effects of different scenarios for the Sun's activity evolution. I will show the importance of these factors for the exosphere and escape processes of the Earth and terrestrial planets outside our solar system.</p>

Review Lecture: Origin of the chemical elements

1984 ◽  
Vol 396 (1810) ◽  
pp. 21-54 ◽  
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
Chemical Elements ◽  
Big Bang ◽  
Initial Composition ◽  
Initial Chemical Composition ◽  
Stellar Formation ◽  
Different Types ◽  
Formation And Evolution ◽  
The Universe

An account is first given of the observed chemical composition of objects in the Universe (Sun, Solar System, stars, gas clouds) and of important variations of composition from object to object. The initial composition is then discussed in terms of the Hot Big Bang cosmological theory, and the different types of nuclear reaction which are believed to have occurred in stars and to have modified this composition are considered. Finally, an account is given of the interpretation of the present observations in terms of the initial chemical composition and of galactic and stellar formation and evolution.

scholarly journals Biosignatures in the solar system

2018 ◽  
Vol 40 (6) ◽  
pp. 6-9
Author(s):  
David Slade ◽  
Alex Price ◽  
Rachael Hamp ◽  
Nisha Ramkissoon
Keyword(s):  
Solar System ◽  
16Th Century ◽  
Planetary Bodies ◽  
Planets And Satellites ◽  
Life Detection ◽  
Life On Earth ◽  
The Universe ◽  
Intelligent Life

Humanity's interest in whether or not we are alone in the universe spans generations, from Giordano Bruno's 16th century musings on other worlds and Giovanni Schiaparelli reporting seeing ‘canali’ in 1877 on the surface of Mars (which were thought to have been created by intelligent life) to alien invasions portrayed in today's movies. However, it is still unclear if other planetary bodies are capable of supporting life. In the search for life there are two broad areas we look into, the requirements of life and actual signs of life. The identification of the key requirements for life enables scientists to focus life detection efforts onto planets and satellites that are considered habitable and more likely to support life. However, our ability to find life or detect signs of life is based on our understanding of life on Earth.

scholarly journals The effect of our local motion on the Sandage–Loeb test of the cosmic expansion

2019 ◽  
Vol 72 (1) ◽  
Author(s):  
Takuya Inoue ◽  
Eiichiro Komatsu ◽  
Wako Aoki ◽  
Takeshi Chiba ◽  
Toru Misawa ◽  
...  
Keyword(s):  
Solar System ◽  
Local Group ◽  
Galactic Center ◽  
Large Magellanic Cloud ◽  
Local Motion ◽  
Microwave Background ◽  
Cosmic Expansion ◽  
M 31 ◽  
The Universe

Abstract Redshifts of an astronomical body measured at multiple epochs (e.g., separated by 10 yr) are different due to the cosmic expansion. This so-called Sandage–Loeb test offers a direct measurement of the expansion rate of the Universe. However, acceleration in the motion of the Solar System with respect to the cosmic microwave background also changes redshifts measured at multiple epochs. If not accounted for, it yields a biased cosmological inference. To address this, we calculate the acceleration of the Solar System with respect to the Local Group of galaxies to quantify the change in the measured redshift due to local motion. Our study is motivated by the recent determination of the mass of the Large Magellanic Cloud (LMC), which indicates a significant fraction of the Milky Way mass. We find that the acceleration towards the Galactic Center dominates, which gives a redshift change of 7 cm s−1 in 10 yr, while the accelerations due to the LMC and M 31 cannot be ignored, depending on lines of sight. We create all-sky maps of the expected change in redshift and the corresponding uncertainty, which can be used to correct for this effect.

scholarly journals Determınation of the Opinions and Expectations of Nursing Students About Clinical Nurses

2020 ◽  
Author(s):  
Münevver Sönmez ◽  
Öznur Gürlek Kısacık
Keyword(s):  
Nursing Students ◽  
Role Models ◽  
Sample Selection ◽  
Clinical Nurses ◽  
Descriptive Research ◽  
Questionnaire Form ◽  
The Right ◽  
Nursing Department ◽  
The Universe

INTRODUCTION: The aim of this study was to evaluate the opinions and the expectations of nursing students about clinical nurses METHODS: This descriptive research was carried out in the Nursing department of a public university. Sample selection and 68.7% of the universe has been reached. The data were collected by using the related literature with the “Questionnaire Form” created by the researchers. RESULTS: The nursing students stated that the nurses could not allocate sufficient time for them because of their workload (49.0%) and the high number of students (53.0%). In addition, it was determined in the study that nurses saw students as people who reduced their workload (60.1%) and nurses expected students to do non-patient jobs in the clinic (51.0%). DISCUSSION AND CONCLUSION: In the study, it was determined that the nurses were insufficient to be the right role models for the nursing students.

1. Beginnings

2021 ◽  
pp. 1-13
Author(s):  
Raymond T. Pierrehumbert
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Solar System ◽  
Planetary Systems ◽  
Big Bang ◽  
Giant Planets ◽  
Baryonic Matter ◽  
Rocky Planets ◽  
The Big Bang ◽  
The Universe

‘Beginnings’ discusses the general processes that form planetary systems, particularly the Solar System. Most of the Universe is made of a mysterious substance called ‘dark matter’, and an even more mysterious substance called ‘dark energy’. After the birth of the Universe in the Big Bang, the tiny bits of stardust which have accumulated contain the heavier elements (baryonic matter) that make it possible to form beings like ourselves, and the planets on which we live. We mustn't forget the importance of the formation of protostars, as well as gas and ice giant planets, the evolution of the proto-Sun, and the formation of inner rocky planets.

scholarly journals The Real Unıverse Model

2020 ◽  
Vol 5 (8) ◽  
pp. 846-848
Author(s):  
Mammadov Sabir Ahmedovich
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
Universe Model ◽  
The Real ◽  
The Universe ◽  
Real Universe

The developed cosmogonic theory and laws explain the objective solution of the problem of cosmogony - the universe, antiquity, solar system, planets and their satellites the origin and development, as well as their structure and chemical composition. At the same time, objective reasons for the formation of water and life in the solar system are given.

Cosmic Chemistry

2017 ◽  
Author(s):  
John Chambers ◽  
Jacqueline Mitton
Keyword(s):  
Solar System ◽  
Chemical Elements ◽  
Building Blocks ◽  
Big Bang ◽  
Rich Variety ◽  
Gold Silver ◽  
The Rich ◽  
Rocky Planets ◽  
The Big Bang ◽  
The Universe

This chapter analyzes how humans owe their existence to the rich variety of chemical elements that exist in the universe. The solar system contains hydrogen to power the Sun; iron and silicon to build rocky planets; and carbon, nitrogen, and oxygen to form the building blocks of life. Almost 100 elements occur naturally in the solar system in varying amounts. Some, like hydrogen, oxygen, and iron, are abundant everywhere. Others, like gold, silver, and uranium, are much less common. The mixture of elements has remained almost constant since the solar system formed, apart from changes deep in the Sun's interior. The chapter shows how the composition of the solar system was shaped by events elsewhere in the universe dating back to the Big Bang itself.

Abundance Variations Among Young Clusters and Associations

1980 ◽  
Vol 85 ◽  
pp. 51-70 ◽  
Author(s):  
Poul E. Nissen
Keyword(s):  
Chemical Composition ◽  
Chemical Evolution ◽  
Star Clusters ◽  
Open Clusters ◽  
The Other ◽  
Stellar Structure ◽  
Open Clusters And Associations ◽  
The Galaxy ◽  
The Universe

The aim of this paper is to give a review of our knowledge of the chemical composition of young groups of stars in the Galaxy, i.e. open clusters and associations with ages less than about 109 years. In particular I shall discuss if abundance differences between these groups of stars do occur, and how large these possible differences can be. Such information is important in many astronomical fields. Thus, abundance differences between star clusters complicate the determination of their distances by ZAMS-fitting, and make the distance scale in the Universe more uncertain. Comparisons between theoretical isochrones and cluster sequences in color-magnitude diagrams with the purpose of testing the theory of stellar structure and evolution are also much more difficult if differences in abundances have to be taken into account. On the other hand the determination of abundances of clusters and associations as a function of their ages and places of formation give important information on the chemical evolution of our galaxy, in particular because abundances, ages and space velocities for clusters and associations can be determined much more accurate than for single stars.

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