life
where
as
present?
1.where life is present
Answers
Explanation:
Are we alone in the universe? Sages and scientists, philosophers and poets have posed variants of this question since time immemorial. Today, we are formulating research programs that may someday provide an answer. We are in this enviable position thanks to the intertwining of three scientific and associated technological threads developed over the past 400 years.
Astronomical sciences—The era of modern astronomy began in the 16th and 17th centuries when Copernicus, Brahe, Galileo, and Kepler enabled the delineation of orbits of planets and satellites in the solar system. Today, their successors are doing the same for planets orbiting other stars (exoplanets). Moreover, astronomers have shown that the elements required for life (e.g., carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur) are present across our galaxy and countless others, raising the possibility not only for habitable environments beyond the solar system, but also for life itself.
Geological sciences—Development of the theory of uniformitarianism by Hutton and Playfair at the end of the 18th century began a revolution in our understanding of Earth’s structure, evolution, and age. Today, techniques such as isotopic dating, electron microscopic imaging, and seismological analysis, coupled with theories such as plate tectonics, have produced a deep understanding of the nature of Earth as a planet while continuing to uncover new insights and frontiers. With the coming of the space age, geologists began applying knowledge gained from the study of Earth to other bodies in the solar system. This has evolved into an interdisciplinary quest to evaluate the habitability of bodies both in this solar system and in planetary systems around other stars.
Biological sciences—The twin 19th-century developments of Darwin’s theory of evolution and Mendel’s theory of genetics, coupled with the contemporaneous microbiological insights of Pasteur, brought understanding of the nature of life on Earth into the modern age. In the early-20th century, Haldane and Oparin independently proposed that the origin of life was a natural consequence of environmental conditions on the early Earth—an idea later supported by the experiments of Miller and Urey. The last half of the 20th century saw a revolution in the understanding of biological systems exemplified by the deciphering of the genetic code and the discovery of the three domains of life. The discovery of deep-sea hydrothermal vents and their associated ecosystems, powered by chemical reactions, suggested new venues for life’s origins and novel habitable zones in Earth’s subsurface, while advances in biotechnology provided new approaches to life detection.