Search results for "astrobiology"
showing 10 items of 70 documents
Observational data and orbits of the asteroids discovered at the Baldone Observatory in 2015–2018
2020
AbstractThis paper is devoted to the discovery of 37 asteroids at the Baldone Astrophysical Observatory (MPC 069) from 2015 to 2018, and one of dynamically interesting Mars-crosser (MC) observed at the Baldone Astrophysical Observatory, namely 2008 LX16. In Baldone Observatory, was independently discovered the Near-Earth Object 2018 GE3 on the image of 13 April 2018. Also, the NEO 2006 VB14 was observed doing its astrometry and photometry. Moreover, we observed asteroids 1986 DA and 2014 LJ1. We computed orbits and analyzed the orbital evolution of these asteroids. 566 positions and photometric observations of NEO objects 345705 (2006 VB14) and 6178 (1986 DA) were obtained with Baldone Schm…
Diving into exoplanets: Are water seas the most common?
2019
One of the basic tenets of exobiology is the need for a liquid substratum in which life can arise, evolve, and develop. The most common version of this idea involves the necessity of water to act as such a substratum, both because that is the case on Earth and because it seems to be the most viable liquid for chemical reactions that lead to life. Other liquid media that could harbor life, however, have occasionally been put forth. In this work, we investigate the relative probability of finding superficial seas on rocky worlds that could be composed of nine different, potentially abundant, liquids, including water. We study the phase space size of habitable zones defined for those substance…
Secondary minerals from salt caves in the Atacama Desert (Chile): a hyperarid and hypersaline environment with potential analogies to the Martian sub…
2017
Over the past 15 years several expeditions by French, American and especially Italian cavers have unveiled over 50 caves in the Cordillera de la Sal (Atacama Desert, Northern Chile). Many of these caves contain a variety of speleothems and minerals, some of which have rarely been observed within karst systems. Most of the secondary deposits in these caves are composed of halite, but also other halide, carbonate, sulphate, nitrate, phosphate, and silicate minerals have been found. Among the sixteen cave mineral species recognized, atacamite, darapskite, blödite, leonite, anhydrite, and especially antarcticite are worth mentioning. In one of the samples an unknown Ca-Sr-bearing chloride miner…
The Philae lander mission and science overview.
2017
The Philae lander accomplished the first soft landing and the first scientific experiments of a human-made spacecraft on the surface of a comet. Planned, expected and unexpected activities and events happened during the descent, the touch-downs, the hopping across and the stay and operations on the surface. The key results were obtained during 12–14 November 2014, at 3 AU from the Sun, during the 63 h long period of the descent and of the first science sequence on the surface. Thereafter, Philae went into hibernation, waking up again in late April 2015 with subsequent communication periods with Earth (via the orbiter), too short to enable new scientific activities. The science return of the…
Prebiotic Evolution and the Origin of Life: Chemical and Biochemical Aspects
1988
Evolution, as the term is used here, signifies any development or change adapting to the environment. Chemical evolution connotes changes of chemical substances, it thus signifies that changes occur fundamentally in the molecules. Frequently “chemical evolution” is used synonymously for “abiotic” or “prebiotic formation” of organic molecules in a cosmic system, usually on the prebiotic (or primitive) Earth. It is then assumed that the organic molecules were formed from the constituents of the primitive atmosphere, hydrosphere, and — in part — lithospere.
Origin of Life, Theories Of
2017
Modern advances in biology, geology, chemistry, and astronomy have allowed us to elaborate models and hypotheses on the origin of life on Earth within the framework of the evolutionary theory. About four billion years ago, a rich inventory of organic compounds accumulated on the planet, as a product of volcanic, atmospheric, and cosmic chemistry. As chemical systems became increasingly more complex, a critical point was reached with the appearance of self-replicative polymers. This marks the possibility of optimizing abiotic systems by natural selection and historical contingency, which were added to the determinism of abiotic chemistry. A landmark of the origin of life was the articulation…
Secondary School Students' Knowledge and Opinions on Astrobiology Topics and Related Social Issues.
2017
Astrobiology is the study of the origin of life on Earth and the distribution of life in the Universe. Its multidisciplinary approach, social and philosophical implications, and appeal within the discipline and beyond make astrobiology a uniquely qualified subject for general science education. In this study, student knowledge and opinions on astrobiology topics were investigated. Eighty-nine students in their last year of compulsory education (age 15) completed a written questionnaire that consisted of 10 open questions on the topic of astrobiology. The results indicate that students have significant difficulties understanding the origin of life on Earth, despite exposure to the topic by w…
Philae's first days on the comet
2015
On 12 November 2014, Philae landed on the surface of comet 67P/Churyumov-Gerasimenko (67P), making an almost 30-year dream a reality. The pioneering flybys of 1P/Halley in 1986 revealed that despite being made primarily of ice, it was covered in highly absorbing carbonrich molecules. What is their composition? When did they form, and through which chemical routes? Might they have constituted prebiotic molecules necessary for life? At a larger scale, what can one learn from comets that has relevance to the evolution of the solar system and planets? ![Figure][1] 12 NOVEMBER 2014: PHILAE LANDED ON THE NUCLEUS OF COMET 67P CREDIT: ESA/ROSETTA/MPS FOR OSIRIS TEAM MPS/UPD/LAM/IAA/SSO/INTA/UPM/DAS…
Report of the COSPAR Mars special regions colloquium
2010
International audience; In this paper we present the findings of a COSPAR Mars Special Regions Colloquium held in Rome in 2007. We review and discuss the definition of Mars Special Regions, the physical parameters used to define Mars Special Regions, and physical features on Mars that can be interpreted as Mars Special Regions. We conclude that any region experiencing temperatures > -25 degrees C for a few hours a year and a water activity > 0.5 can potentially allow the replication of terrestrial microorganisms. Physical features on Mars that can be interpreted as meeting these conditions constitute a Mars Special Region. Based on current knowledge of the martian environment and the conser…
Opportunity Mars Rover mission: Overview and selected results from Purgatory ripple to traverses to Endeavour crater
2011
Opportunity has been traversing the Meridiani plains since 25 January 2004 (sol 1), acquiring numerous observations of the atmosphere, soils, and rocks. This paper provides an overview of key discoveries between sols 511 and 2300, complementing earlier papers covering results from the initial phases of the mission. Key new results include (1) atmospheric argon measurements that demonstrate the importance of atmospheric transport to and from the winter carbon dioxide polar ice caps; (2) observations showing that aeolian ripples covering the plains were generated by easterly winds during an epoch with enhanced Hadley cell circulation; (3) the discovery and characterization of cobbles and boul…