geografia: Rare Earth hypothesis

Evidence: 100 • authority: 72

In planetary astronomy and astrobiology, the Rare Earth hypothesis argues that the origin of life and the evolution of biological complexity, such as sexually reproducing, multicellular organisms on Earth, and subsequently human intelligence, required an improbable combination of astrophysical and geological events and circumstances. According to the hypothesis, complex extraterrestrial life is an improbable phenomenon and likely to be rare throughout the universe as a whole. The term "Rare Earth" originates from Rare Earth: Why Complex Life Is Uncommon in the Universe (2000), a book by Peter Ward, a geologist and paleontologist, and Donald E. Brownlee, an astronomer and astrobiologist, bot…

Evidence: 48 • authority: 90

On the origin of life on earth. dinates.This anthropomorphism is certainly a reductionism.The way of acting of an eternal and infinite Creator ultimately remains elusive and is a mystery.In an unprecedented way, Ratzinger postulated that "the becoming of created matter is a moment in the history of the spirit" 3 .In a way, it could be expressed as a reformulation of Einstein's masterful equation E = mc 2 , where this time "E" would not be energy but spirit; "m" would represent matter rather than mass, and the space-temporal becoming would correspond to "c 2 ".Admitted that a direct divine intervention would explain the creation of the universe out of nothing, ex nihilo 4,5 , how could other…

Evidence: 48 • authority: 72

The natural history of Earth concerns the development of planet Earth from its formation to the present day. Nearly all branches of natural science have contributed to the understanding of the main events of Earth's past, characterized by constant geological change and biological evolution. The geological time scale (GTS), as defined by international convention, depicts the large spans of time from the beginning of Earth to the present, and its divisions chronicle some definitive events of Earth history. Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphe…

Evidence: 48 • authority: 72

The Snowball Earth is a geohistorical hypothesis proposing that during one or more of Earth's icehouse climates, the planet's surface was nearly entirely frozen, with little or no liquid water exposed. This global glaciation hypothesis is most commonly associated with the Cryogenian Period, which included two major glacial episodes: the Sturtian (c. 717–660 Ma) and Marinoan (c. 650–635 Ma). Proponents of the hypothesis argue that it best explains sedimentary deposits that are generally believed to be of glacial origin at tropical palaeolatitudes and other enigmatic features in the geological record. Opponents of the hypothesis contest the geological evidence for global glaciation and the ge…

Evidence: 47 • authority: 90

The Hot Spring Hypothesis for an Origin of Life. We present a testable hypothesis related to an origin of life on land in which fluctuating volcanic hot spring pools play a central role. The hypothesis is based on experimental evidence that lipid-encapsulated polymers can be synthesized by cycles of hydration and dehydration to form protocells. Drawing on metaphors from the bootstrapping of a simple computer operating system, we show how protocells cycling through wet, dry, and moist phases will subject polymers to combinatorial selection and draw structural and catalytic functions out of initially random sequences, including structural stabilization, pore formation, and primitive metabolic…

Evidence: 43 • authority: 88

The Origin of Life on Earth, the Panspermia Hypothesis and Cosmological DNA Synthesis. The process of the rapid origin of life on Earth is analyzed, taking into account the evolution of our Sun (the beginning of thermonuclear reactions). Given the knowledge about DNA, viruses and the structure of bacteria, it is concluded that the origin of life on Earth was initiated from the outside. Further, using space chemistry, it is shown that spontaneous assembly of DNA/RNA molecules can occur on particles of interstellar and intergalactic dust. Therefore, when favorable conditions are created on the planet, the emergence of life begins rapidly, since the initiators of life are already available fro…

Evidence: 43 • authority: 72

Rare Earth: Why Complex Life Is Uncommon in the Universe is a 2000 popular science book about xenobiology by Peter Ward, a geologist and evolutionary biologist, and Donald E. Brownlee, a cosmologist and astrobiologist. The book is the origin of the term 'Rare Earth Hypothesis' which denotes the central claim of the book: that complex life is rare in the universe.

Evidence: 38 • authority: 88

On the Origin of Life on Earth: The Nanozymes Hypothesis, and More. The origin of life (OoL) is a fundamental and long-standing scientific question. Although a variety of plausible hypotheses had been put forward, how life began on the prebiotic Earth from a pile of prehistoric inert chemicals (gases) is still a puzzle to us. Here, to unify the existing hypotheses to cover the entire scenarios, the author proposed the “nanozymes hypothesis” of the OoL on Earth, in which natural mineral nanozymes (MN-zymes) and their later upgraded organic/inorganic hybridized nanozymes played multiple key roles in the initial emergence of life molecules, especially in the manner of “inorganic photosynthesis…

Evidence: 38 • authority: 90

On the Early Chemical History of the Earth and the Origin of Life. Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.. Source: Proceedings of the National Academy of Sciences. Year: 1952

Evidence: 33 • authority: 80

Mass Extinctions and the Rare Earth Hypothesis

Evidence: 33 • authority: 72

The earliest known life forms on Earth may be as old as 4.1 billion years (or Ga) according to biologically fractionated graphite inside a single zircon grain in the Jack Hills range of Australia. The earliest evidence of life found in a stratigraphic unit, not just a single mineral grain, is the 3.7 Ga metasedimentary rocks containing graphite from the Isua Supracrustal Belt in Greenland. The earliest, directly known life on Earth are stromatolite fossils which have been found in 3.480-billion-year-old geyserite uncovered in the Dresser Formation of the Pilbara Craton of Western Australia. Various microfossils of microorganisms have been found in 3.4 Ga rocks, including 3.465-billion-year-…