Search results
Results from the WOW.Com Content Network
The PAH world hypothesis is a speculative hypothesis that proposes that polycyclic aromatic hydrocarbons (PAHs), known to be abundant in the universe, [178] [179] [180] including in comets, [181] and assumed to be abundant in the primordial soup of the early Earth, played a major role in the origin of life by mediating the synthesis of RNA ...
The hypothesis of Andreas Cellarius, showing the planetary motions in eccentric and epicyclical orbits. A hypothesis (pl.: hypotheses) is a proposed explanation for a phenomenon. A scientific hypothesis must be based on observations and make a testable and reproducible prediction about reality, in a process beginning with an educated guess or ...
Primordial soup, also known as prebiotic soup and Haldane soup, is the hypothetical set of conditions present on the Earth around 3.7 to 4.0 billion years ago. It is an aspect of the heterotrophic theory (also known as the Oparin–Haldane hypothesis) concerning the origin of life, first proposed by Alexander Oparin in 1924, and J. B. S. Haldane in 1929.
The Arecibo message (1974) sent information into space about basic chemistry of Earth life. A shadow biosphere is a hypothetical microbial biosphere of Earth that uses radically different biochemical and molecular processes than currently known life.
Antonie van Leeuwenhoek. Traditional religion attributed the origin of life to deities who created the natural world. Spontaneous generation, the first naturalistic theory of abiogenesis, goes back to Aristotle and ancient Greek philosophy, and continued to have support in Western scholarship until the 19th century. [15]
The history of scientific method considers changes in the methodology of scientific inquiry, not the history of science itself. The development of rules for scientific reasoning has not been straightforward; scientific method has been the subject of intense and recurring debate throughout the history of science, and eminent natural philosophers and scientists have argued for the primacy of ...
Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. [1] [2] Modern science is typically divided into two or three major branches: [3] the natural sciences (e.g., physics, chemistry, and biology), which study the physical world; and the social sciences (e.g., economics, psychology, and sociology), which ...
The definition of life has long been a challenge for scientists and philosophers. [ 2 ] [ 3 ] [ 4 ] This is partially because life is a process, not a substance. [ 5 ] [ 6 ] [ 7 ] This is complicated by a lack of knowledge of the characteristics of living entities, if any, that may have developed outside Earth.