DOCSLIB.ORG

Cometary Panspermia a Radical Theory of Life’S Cosmic Origin and Evolution …And Over 450 Articles, ~ 60 in Nature

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cometary Panspermia a Radical Theory of Life’S Cosmic Origin and Evolution …And Over 450 Articles, ~ 60 in Nature 35 books: Cosmic origins of life 1976-2020 Physical Sciences︱ Chandra Wickramasinghe Cometary panspermia A radical theory of life’s cosmic origin and evolution …And over 450 articles, ~ 60 in Nature he combined efforts of generations supporting panspermia continues to Prof Wickramasinghe argues that the seeds of all life (bacteria and viruses) Panspermia has been around may have arrived on Earth from space, and may indeed still be raining down some 100 years since the term of experts in multiple fields, accumulate (Wickramasinghe et al., 2018, to affect life on Earth today, a concept known as cometary panspermia. ‘primordial soup’, referring to Tincluding evolutionary biology, 2019; Steele et al., 2018). the primitive ocean of organic paleontology and geology, have painted material not-yet-assembled a fairly good, if far-from-complete, picture COMETARY PANSPERMIA – cultural conceptions of life dating back galactic wanderers are normal features have argued that these could not into living organisms, was first of how the first life on Earth progressed A SOLUTION? to the ideas of Aristotle, and that this of the cosmos. Comets are known to have been lofted from the Earth to a coined. The question of how from simple organisms to what we can The word ‘panspermia’ comes from the may be the source of some of the have significant water content as well height of 400km by any known process. life’s molecular building blocks see today. However, there is a crucial ancient Greek roots ‘sperma’ meaning more hostile resistance the idea of as organics, and their cores, kept warm Bacteria have also been found high in spontaneously assembled gap in mainstream understanding - seed, and ‘pan’, meaning all. In the panspermia commonly evokes. If and by natural radioactivity, are argued by the stratosphere, residing naturally up themselves into something how life’s chemical building blocks model of cometary panspermia, the first when the concept is conceded it will Wickramasinghe to contain pockets of to 41km above Earth’s surface (Harris et that could self-replicate – an assembled themselves into something life on Earth did not spring into being surely rank among al. 2002; Wainwright informationally mega-rich living that would self-replicate and evolve into in some nutrient-rich pocket of the the most important et al. 2004). Microbial organism – remains unanswered. the magnificent panorama of life on ocean, but arrived on Earth from comets. breakthroughs in The Earth is then just another habitat communities have Meanwhile Chandra our planet. After decades of research Furthermore, it wasn’t a single, special, over a century. been found surviving Wickramasinghe and his team of and experimentation, no one has yet comet that brought life to Earth - rather, amongst many trillions in the cosmos, after 100 million international collaborators have been able to produce or propose a the cosmos is awash with life in the form of BUT HOW CAN years buried under been arguing that the seeds of where the cosmic legacy of life is firm mechanism by which life could bacteria and viruses. These microbes are LIFE SURVIVE IN ocean sediment all life (bacteria and viruses) may spontaneously emerge from inanimate stored and nurtured in comets and planets SPACE? nourished and can thrive. (Morono et al. 2020). instead have arrived on Earth material. Proponents of a theory called and are present in interstellar dust clouds. In the theory The observed ability from space, and may indeed still cometary panspermia argue that the of cometary panspermia, comets are liquid water for microbes to survive in of life to survive in hostile conditions, be raining down to affect life on speed at which life emerged on Earth, This idea sounds utterly out of place carriers of life, providing a stable vehicle (Hoyle and Wickramasinghe, 1985). or lie close-to-dormant for millions of Earth today, a concept known as combined with the exceedingly long alongside common conceptions of to transport bacteria and viruses across years and emerge to create healthy cometary panspermia. odds of the random assembly of self- Earth as the only known refuge for space, between cosmic dust clouds Bacteria have been found able populations, lends some credence to replicating molecules, would make the life in an otherwise barren and hostile and star systems. With the recent to survive on the outside of the idea of cosmic comet-bound travel. spontaneous appearance of life on Earth cosmos. Wickramansinghe argues that observations of two comets visiting our the International Space Station nothing short of miraculous (Hoyle and panspermia not only goes against the solar system from elsewhere (‘Oumouma (Grebennikova, T.V., et al. 2018). But comets are still bleak, barren objects Wickramasinghe, 1982, 2000). Meanwhile prevailing scientific doctrines regarding and Comet Borisov), we can see that Wickramasinghe and Rycroft (2018) fully exposed to the intense radioactive a diverse range of scientific evidence life, but ingrained, long-term western Marko Aliaksandr/Shutterstock.com Marko At the Institute of Oriental Philosophy, Tokyo. www.researchfeatures.com www.researchfeatures.com Behind the Research Prof Chandra Wickramasinghe E: [email protected] T: +44 7778389243 W: https://profchandra.org/ W: https://panspermia.org/ Research Objectives Detail Panspermia proposes that bodies such as comets transported life forms such as bacteria—complete with Professor Chandra Wickramasinghe has made ground-breaking Bio their DNA—through space to the Earth. contributions to exploring the nature of cosmic dust, its role in Professor Nalin Chandra Wickramasinghe was born in astrophysics, and its relevance to the understanding of life in the Universe. Sri Lanka and educated at Royal College, Colombo and commons.wikimedia.org/wiki/File:Panspermie_2.0.svg later at the University of Ceylon. In 1960 he obtained a First Class Honours degree in Mathematics and bombardment and temperature extremes As mentioned previously, life has been in a 2018 paper, the unique features and References won a Commonwealth scholarship to Trinity College of space. Is it really possible that found by high altitude balloons flown rapid evolution of octopi were argued Cambridge. He commenced work in Cambridge on his PhD degree under the supervision of the late Sir Fred organisms ferried on comets would be into the stratosphere (Harris et al. 2002). to be taken as signals of the presence of Grebennikova T.V., et al. (2018). The DNA of Bacteria of the World Ocean and the Earth in Cosmic Dust at the International Space Station. Scientific Hoyle, and published his first scientific paper in 1961. able to seed a planet after tens of millions One possible explanation as to how these alien DNA (Steele et al. 2018). Pandemics World Journal. https://doi.org/10.1155/2018/7360147 He was awarded a PhD degree in 1963, ScD degree in of years in transit? Survival may indeed be bacteria got there is strong winds blowing of viral disease throughout history and Harris, M.J, et al. (2002). Detection of living cells in stratospheric samples. 1973, and was a Fellow of Jesus College Cambridge possible in the protected deep interiors them up from the surface. However, even now may well have a cometary Proc. SPIE 4495, Instruments, Methods, and Missions for Astrobiology IV, (5 from 1963−1973. He was also a Staff Member of the February 2002) Institute of Astronomy at the University of Cambridge of comets, but what of survival once living Wickramasinghe asserts that this is not provenance according to Wickramasinghe over the same period. Here he began his pioneering cells leave the comets? possible and they may in fact be raining (Hoyle and Wickramasinghe, 1979, Qu Hoyle, F., Wickramasinghe, N.C., (1979). Diseases from Space. J.M. Dent work on the nature of Interstellar Dust, publishing many and Sons, Lond. down directly from space, at the prolific and Wickramasinghe, 2020, Steele et papers in this field that led to important paradigm shifts Hoyle, F., Wickramasinghe, N.C., (1982). Evolution from Space. J.M. Dent The harsh environment of space may rate of tonnes of microbes per day over al. 2020). in astronomy. He was a Professor at University College and Sons, Lond. Cardiff and Cardiff University from 1974−2011. He has indeed wipe out the vast majority of any the whole Earth (Wainwright et al. 2004, Hoyle, F., Wickramasinghe, N.C., (1985). Living Comets. University College held visiting Professorial appointments in the US, Canada iterant life, but life is, by definition, good Wickramasinghe et al. 2020). THE FUTURE OF PANSPERMIA Cardiff Press, Cardiff and Japan and Sri Lanka at various times. In 1983/84 he at surviving and replicating exponentially. The theory of panspermia and its Morono, Y., et al. (2020). Aerobic microbial life persists in oxic marine was Science Advisor to the President of Sri Lanka and Founder Director of the Institute of Fundamental Studies If only a few viable microbes, of an initial If this is indeed the case, and Earth will profound implications have attracted sediment as old as 101.5 million years. Nat Comm 11, https://doi. org/10.1038/s41467-020-17330-1 in Sri Lanka. He is currently Honorary Professor at the population of trillions, survive the transit be subject to a constant rain of alien sustained, strong often irrational rebukes University of Buckingham, UK, University of Ruhuna, Sri Slijepcivic, P. and Wickramasinghe, C. (2021). Reconfiguring SETI in the Lanka and an Adjunct Professor at the National Institute between viable planets, then these microbes, it stands to reason that we from multiple scientific disciplines microbial context: Panspermia as a solution to Fermi’s paradox. Biosystems of Fundamental Research in Sri Lanka. comet-borne microbes could be the should be able to detect alien genomes ranging from astrophysics to genetics to 206, 104441 (see also - https://theconversation.com/seti-how-microbes- seeds of life on multiple worlds.
Load more

Recommended publications
  • Modelling Panspermia in the TRAPPIST-1 System
    October 13, 2017 Modelling panspermia in the TRAPPIST-1 system James A. Blake1,2*, David J. Armstrong1,2, Dimitri Veras1,2 Abstract The recent ground-breaking discovery of seven temperate planets within the TRAPPIST-1 system has been hailed as a milestone in the development of exoplanetary science. Centred on an ultra-cool dwarf star, the planets all orbit within a sixth of the distance from Mercury to the Sun. This remarkably compact nature makes the system an ideal testbed for the modelling of rapid lithopanspermia, the idea that micro-organisms can be distributed throughout the Universe via fragments of rock ejected during a meteoric impact event. We perform N-body simulations to investigate the timescale and success-rate of lithopanspermia within TRAPPIST-1. In each simulation, test particles are ejected from one of the three planets thought to lie within the so-called ‘habitable zone’ of the star into a range of allowed orbits, constrained by the ejection velocity and coplanarity of the case in question. The irradiance received by the test particles is tracked throughout the simulation, allowing the overall radiant exposure to be calculated for each one at the close of its journey. A simultaneous in-depth review of space microbiological literature has enabled inferences to be made regarding the potential survivability of lithopanspermia in compact exoplanetary systems. 1Department of Physics, University of Warwick, Coventry, CV4 7AL 2Centre for Exoplanets and Habitability, University of Warwick, Coventry, CV4 7AL *Corresponding author: [email protected] Contents Universe, and can propagate from one location to another. This interpretation owes itself predominantly to the works of William 1 Introduction1 Thompson (Lord Kelvin) and Hermann von Helmholtz in the 1.1 Mechanisms for panspermia...............2 latter half of the 19th Century.
    [Show full text]
  • Analysis of the Absorption of Science Learning in National Examinations in 2019 at the Junior High School Level in Sleman District
    INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 9, ISSUE 03, MARCH 2020 ISSN 2277-8616 Analysis Of The Absorption Of Science Learning In National Examinations In 2019 At The Junior High School Level In Sleman District Muhammad Minan Chusni, Sulistyo Saputro, Suranto, Sentot Budi Rahardjo Abstract: This study aims to describe the ability of students in national examinations in science learning in terms of their absorption. The method used in this study was a survey with a quantitative approach. The object of research is 146 junior high schools with a total of 14,983 students in the Sleman district. The data used were the national exam's absorption of science learning provided by the education assessment center of the ministry of education and culture. The results showed that the highest mean of absorption is in the material aspects of mechanics and the solar system of 71.60 which is classified as good category, while the lowest average is in the material aspects of waves, electricity and magnetism at 45.56 which is classified as fewer categories. In addition, the lowest mean on the indicator question about waves, electricity and magnetism is "presenting an illustration of two people with eye defects wearing glasses and then determining the ratio of reading distance between the two people" amounted to 28.39, which is classified as very poor category. From these results it can be concluded that the indicator questions about optical material in the ability to analysis are still very poor. Keyword: Science Learning, National Examination. —————————— —————————— 1. INTRODUCTION As for nationally it is used as a mapping of the quality of Education and progress of a nation are two related things [1].
    [Show full text]
  • Representations in Sustainability Science
    REPRESENTATIONS IN SUSTAINABILITY SCIENCE TOOLS TO ANALYZE, ENVISION, ENGAGE, AND LEARN BEATRICE JOHN “Representation in Sustainability Science: Tools to Analyze, Envision, Engage, and Learn” Academic dissertation Submitted to the Faculty of Sustainability of Leuphana University for the award of the degree Doctor of Philosophy -Dr. phil.- approved by Beatrice John, born Feb 18, 1985, in Achern Submission: January 7, 2019 Defense: March 25, 2019 Supervisor and first reviewer: Prof. Dr. Daniel J. Lang Second reviewer: Prof. Dr. Henrik von Wehrden Third reviewer: Prof. Dr. John Holmberg The articles included here, which together form this cumulative dissertation, have been or will be published in the formats listed below. Chapters 1-3 and 5-6 framing of this thesis may be published in future. John, B., Lang, D.J., von Wehrden, H., John, R., Wiek, A., n.d. Advancing Decision-Visualization Environments-empirically informed Design Guidelines. doi:10.13140/RG.2.2.26933.32486 John, B., Luederitz, C., Lang, D.J., von Wehrden, H., 2019. Toward Sustainable Urban Metabolisms. From System Understanding to System Transformation. Ecol. Econ. 157, 402–414. doi:10.1016/j.ecolecon.2018.12.007 John, B., Withycombe Keeler, L., Wiek, A., Lang, D.J., 2015. How much sustainability substance is in urban visions? – An analysis of visioning projects in urban planning. Cities 48, 86–98. doi:10.1016/j.cities.2015.06.001 Caniglia, G., John, B., Kohler, M., Bellina, L., Wiek, A., Rojas, C., Laubichler, M.D., Lang, D., 2016. An experience-based learning framework. Activities for the initial development of sustainability competencies. Int. J. Sustain. High.
    [Show full text]
  • INTEGRATION of SCIENCE and LANGUAGE with a FOCUS on MULTILINGUAL LEARNERS: SHARED OPPORTUNITIES and RESPONSIBILITIES Okhee Lee* New York University
    Keynote Conference Address INTEGRATION OF SCIENCE AND LANGUAGE WITH A FOCUS ON MULTILINGUAL LEARNERS: SHARED OPPORTUNITIES AND RESPONSIBILITIES Okhee Lee* New York University This article highlights the importance of promoting science and language learning for all students, especially multilingual learners. In recent years, there have been parallel instructional shifts in science and language with multilingual learners, which enables integration of science and language in mutually supportive ways. These instructional shifts have resulted in new opportunities for collaboration between language educators and science educators as well as development of new instructional resources. Such collaboration and resources are essential for creating equity for multilingual learners. In this article, I describe contemporary perspectives on integrating science and language with multilingual learners across policy, research, and practice. I also provide a classroom example using a unit from the Science And Integrated Language (SAIL) curriculum and a series of webinars and briefs based on the SAIL curriculum for the New York State Education Department. It was an honor to be invited to give a talk at the 50th anniversary of the New York State TESOL conference in 2020. I feel privileged to be included among the group of distinguished speakers invited to address the organization. I am honored again to be invited to write this article for our membership. The purpose of the article is to highlight the importance of promoting science and language learning for multilingual learners. New opportunities for collaboration between language educators and science educators are being forged as well as new instructional resources are being developed. Such collaboration and resources are essential for creating equity for multilingual learners.
    [Show full text]
  • 6 Dynamical Generalizations of the Drake Equation: the Linear and Non-Linear Theories
    6 Dynamical Generalizations of the Drake Equation: The Linear and Non-linear Theories Alexander D. Panov Abstract The Drake equation pertains to the essentially equilibrium situation in a popu- lation of communicative civilizations of the Galaxy, but it does not describe dynamical processes which can occur in it. Both linear and non-linear dynam- ical population analyses are built out and discussed instead of the Drake equa- tion. Keywords: SETI, the Drake equation, linear population analysis, non-linear population analysis. Introduction Communicative civilizations (CCs) are the ones which tend to send messages to other civilizations and are able to receive and analyze messages from other civili- zations. The crucial question of the SETI problem is how far the nearest CC from us is. Its answer depends on the number of CCs existing in the Galaxy at present. Fig. 1 shows how the distance between the Sun and the nearest CC depends on the number of CCs in the Galaxy. The calculation was made by us by the Monte Carlo method with the use of a realistic model of the distribution of stars in the Galaxy (Allen 1973) and the actual location of the Sun in the Galaxy (8.5 kpc from the center of the Galaxy). The best known way to answer the question about the number of CCs is the formula by F. Drake N R f n f f f L C * p e l i c , (Eq. 1) where R∗ is a star-formation rate in the Galaxy averaged with respect to all time of its existence, fp is the part of stars with planet systems, nе is the average number of planets in systems suitable for life, fl is the part of planet on which life did appear, fi is the part of planets on which intelligent forms of life devel- oped, fc is the part of planets on which life reached the communicative phase, L is the average duration of the communicative phase.
    [Show full text]
  • USGS Open-File Report 2005-1190, Appendix A
    USGS Open-File Report 2005-1190 APPENDIX B Detailed listing of personnel changes for the Branch of Astrogeology from 1960 through 1972. In the early 1960’s, the Branch of Astrogeology grew slowly. Growth was rapid during and after 1964 with a maximum of 250 employees being reached in 1970 when design and training for the Apollo missions were at their peaks. [Authors Note: The Branch of Astrogeology in 2006 consisted of approximately 80 employees.] Table 1. Number of Employee with the U.S. Geological Survey, Branch of Astrogeology from 1960 through 1987 [Author’s Note: Although Monthly Reports for Astrogeology were submitted to the USGS and NASA through 1977, new personnel and personnel changes were only documented in these reports through 1970.] Year Number of employees 1960 18 1961 26 1962 40 1963 59 1964 143 1965 154 1966 221 1967 239 1968 244 1969 234 1970 250 1960 The following personnel joined the Astrogeologic Studies Unit at Menlo Park during 1960 (see main text and Appendix A) (various sources): Henry J. Moore II (Geologist, September) Charles H. “Chuck” Marshall (Geologist/Lunar mapper; September) Richard E. Eggleton (Geologist, October) Richard V. Lugn (August) 1961 The following personnel came on duty with the Branch of Astrogeology at Menlo Park, California during 1961 (see main text and Appendix A) (various sources): David J. Roddy (Geologist; January/February) Martin L. Baker (Scientific Photographer; October) Jacquelyn H. Freeberg (Research Librarian and Bibliographer; December) Daniel J. Milton (Geologist; August) Carl H. Roach (Geophysicist; August) 1 Maxine Burgess (Secretary) 1962 The following was taken from the Branch of Astrogeology Monthly Report for April 1962 from Chief, Branch of Astrogeology to V.E.
    [Show full text]
  • Astro2020 Science White Paper Unlocking the Secrets of Late-Stage Stellar Evolution and Mass Loss Through Radio Wavelength Imaging
    Astro2020 Science White Paper Unlocking the Secrets of Late-Stage Stellar Evolution and Mass Loss through Radio Wavelength Imaging Thematic Areas: Planetary Systems Star and Planet Formation Formation and Evolution of Compact Objects Cosmology and Fundamental Physics 7 Stars and Stellar Evolution Resolved Stellar Populations and their Environments Galaxy Evolution Multi-Messenger Astronomy and Astrophysics Principal Author: Name: Lynn D. Matthews Institution: Massachusetts Institute of Technology Haystack Observatory Email: [email protected] Co-authors: Mark J Claussen (National Radio Astronomy Observatory) Graham M. Harper (University of Colorado - Boulder) Karl M. Menten (Max Planck Institut fur¨ Radioastronomie) Stephen Ridgway (National Optical Astronomy Observatory) Executive Summary: During the late phases of evolution, low-to-intermediate mass stars like our Sun undergo periods of extensive mass loss, returning up to 80% of their initial mass to the interstellar medium. This mass loss profoundly affects the stellar evolutionary history, and the resulting circumstellar ejecta are a primary source of dust and heavy element enrichment in the Galaxy. However, many details concerning the physics of late-stage stellar mass loss remain poorly understood, including the wind launching mechanism(s), the mass loss geometry and timescales, and the mass loss histories of stars of various initial masses. These uncertainties have implications not only for stellar astrophysics, but for fields ranging from star formation to extragalactic astronomy and cosmology. Observations at centimeter, millimeter, and submillimeter wavelengths that resolve the radio surfaces and extended atmospheres of evolved arXiv:1903.05592v1 [astro-ph.SR] 13 Mar 2019 stars in space, time, and frequency are poised to provide groundbreaking new insights into these questions in the coming decade.
    [Show full text]
  • Fred Hoyle: Pioneer in Nuclear Astrophysics
    PERSONALITY Fred Hoyle: pioneer in nuclear astrophysics Fred Hoyle, who died in 2001, is best known as a cosmologist. But, as Simon Mitton relates, his career in physics began with the weak interaction and moved on to a crucial discovery in nuclear physics. Fred Hoyle, the great cosmologist, nuclear astrophysicist and contro­ versialist, was born 90 years ago in the beautiful county of Yorkshire in the north of England. Hoyle's first science teacher was his father, who supplied the boy with books and apparatus for chemistry exper­ iments. By the age of 15 he was making highly toxic phosphine (PH3) Later in life Hoyle seldom worked at a desk in a faculty building, in his mother's kitchen, and terrifying his young sister with explosions. preferring a comfortable armchair at home. (St John's College.) In high school he excelled in mathematics, chemistry and physics, and in 1933 won a place at Cambridge to study physics. time Hoyle tracked him down he had just returned from spending six On arrival at Cambridge he immediately demonstrated his fierce months in Rome with Enrico Fermi. Peierls immediately set Hoyle independence by telling his astonished tutor that he was switching the task of improving Fermi's theory of beta decay, published in from physics to applied mathematics. The future nuclear astro­ 1934. This led, in 1937, to Hoyle's first research paper, "The gen­ physicist foresaw that Cambridge mathematics rather than lab­ eralised Fermi interaction". oratory physics would give him the right start as a theorist. The In 1938 Paul Dirac, who had won the Nobel prize in 1933, country boy displayed an astonishing talent at mathematics, even became Hoyle's supervisor because Peierls had left Cambridge for by the highest standards of the university.
    [Show full text]
  • Cosmochemistry Cosmic Background RadiaOn
    6/10/13 Cosmochemistry Cosmic background radiaon Dust Anja C. Andersen Niels Bohr Instute University of Copenhagen hp://www.dark-cosmology.dk/~anja Hauser & Dwek 2001 Molecule formation on dust grains Multiwavelenght MW 1 6/10/13 Gas-phase element depleons in the Concept of dust depleon interstellar medium The depleon of an element X in the ISM is defined in terms of (a logarithm of) its reducon factor below the expected abundance relave to that of hydrogen if all of the atoms were in the gas phase, [Xgas/H] = log{N(X)/N(H)} − log(X/H) which is based on the assumpon that solar abundances (X/H)are good reference values that truly reflect the underlying total abundances. In this formula, N(X) is the column density of element X and N(H) represents the column density of hydrogen in both atomic and molecular form, i.e., N(HI) + 2N(H2). The missing atoms of element X are presumed to be locked up in solids within dust grains or large molecules that are difficult to idenfy spectroscopically, with fraconal amounts (again relave to H) given by [Xgas/H] (Xdust/H) = (X/H)(1 − 10 ). Jenkins 2009 Jenkins 2009 2 6/10/13 Jenkins 2009 Jenkins 2009 The Galacc Exncon Curve Extinction curves measure the difference in emitted and observed light. Traditionally measured by comparing two stars of the same spectral type. Galactic Extinction - empirically determined: -1 -1 <A(λ)/A(V)> = a(λ ) + b(λ )/RV (Cardelli et al. 1999) • Bump at 2175 Å (4.6 µm-1) • RV : Ratio of total to selective extinction in the V band • Mean value is RV = 3.1 (blue) • Low value: RV = 1.8 (green) (Udalski 2003) • High value: RV = 5.6-5.8 (red) (Cardelli et al.
    [Show full text]
  • Interstellar Dust Within the Life Cycle of the Interstellar Medium K
    EPJ Web of Conferences 18, 03001 (2011) DOI: 10.1051/epjconf/20111803001 C Owned by the authors, published by EDP Sciences, 2011 Interstellar dust within the life cycle of the interstellar medium K. Demyk1,2,a 1Université de Toulouse, UPS-OMP, IRAP, Toulouse, France 2CNRS, IRAP, 9 Av. colonel Roche, BP. 44346, 31028 Toulouse Cedex 4, France Abstract. Cosmic dust is omnipresent in the Universe. Its presence influences the evolution of the astronomical objects which in turn modify its physical and chemical properties. The nature of cosmic dust, its intimate coupling with its environment, constitute a rich field of research based on observations, modelling and experimental work. This review presents the observations of the different components of interstellar dust and discusses their evolution during the life cycle of the interstellar medium. 1. INTRODUCTION Interstellar dust grains are found everywhere in the Universe: in the Solar System, around stars at all evolutionary stages, in interstellar clouds of all kind, in galaxies and in the intergalactic medium. Cosmic dust is intimately mixed with the gas-phase and represents about 1% of the gas (in mass) in our Galaxy. The interstellar extinction and the emission of diffuse interstellar clouds is reproduced by three dust components: a population of large grains, the BGs (Big Grains, ∼10–500 nm) made of silicate and a refractory mantle, a population of carbonaceous nanograins, the VSGs (Very Small Grains, 1–10 nm) and a population of macro-molecules the PAHs (Polycyclic Aromatic Hydrocarbons) [1]. These three components are more or less abundant in the diverse astrophysical environments reflecting the coupling of dust with the environment and its evolution according to the physical and dynamical conditions.
    [Show full text]
  • Evolutionary Processes Transpiring in the Stages of Lithopanspermia Ian Von Hegner
    Evolutionary processes transpiring in the stages of lithopanspermia Ian von Hegner To cite this version: Ian von Hegner. Evolutionary processes transpiring in the stages of lithopanspermia. 2020. hal- 02548882v2 HAL Id: hal-02548882 https://hal.archives-ouvertes.fr/hal-02548882v2 Preprint submitted on 5 Aug 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. HAL archives-ouvertes.fr | CCSD, April 2020. Evolutionary processes transpiring in the stages of lithopanspermia Ian von Hegner Aarhus University Abstract Lithopanspermia is a theory proposing a natural exchange of organisms between solar system bodies as a result of asteroidal or cometary impactors. Research has examined not only the physics of the stages themselves but also the survival probabilities for life in each stage. However, although life is the primary factor of interest in lithopanspermia, this life is mainly treated as a passive cargo. Life, however, does not merely passively receive an onslaught of stress from surroundings; instead, it reacts. Thus, planetary ejection, interplanetary transport, and planetary entry are only the first three factors in the equation. The other factors are the quality, quantity, and evolutionary strategy of the transported organisms.
    [Show full text]
  • Fred Hoyle's Universe
    GENERAL ARTICLE Fred Hoyle’s Universe Jayant V Narlikar This article recalls some of the seminal contri- butions to astronomy made by Fred Hoyle. His ideas were thought to be unrealistic at the time they were proposed, but have now been assim- ilated into mainstream science. A general com- ment that emerges from such examples is that highly creative individuals who are far ahead of their times do not get the recognition they de- Jayant V Narlikar is a serve once their ideas are rediscovered and ac- cosmologist and theoretical cepted as standard: for, by the time this hap- astrophysicist. He was a pens, they and their contributions are forgotten. research student and a long-time collaborator of 1. Introduction Fred Hoyle. He is the Founder Director of Fred Hoyle was arguably the most imaginative astro- IUCCA and is currently an emeritus professor there. physicist of the 20th century. He contributed very orig- He has made strong efforts inal ideas to astronomy and astrophysics in topics rang- to promote teaching and ing from the solar system to cosmology. He also made research in astronomy in contributions to fundamental physics, in particular to the universities. He has the concept of action at a distance. His studies on exo- written extensively in English and Marathi to biology evoked the most opposition from the Establish- popularize science. ment because their implications were so far reaching. This article presents glimpses of the work of this mul- tifaceted personality who is also known to the common man as an accomplished science populariser and writer of science ¯ction.
    [Show full text]