The afterlife is a purported existence in which the essential part of an individual's identity or their stream of consciousness continues to live after the death of their physical body. According to various ideas about the afterlife, the essential aspect of the individual that lives on after death may be some partial element, or the entire soul or spirit, of an individual, which carries with it and may confer personal identity or, on the contrary nirvana. Belief in an afterlife is in contrast to the belief in oblivion after death.
Astrobiology, formerly known as exobiology, is an interdisciplinary scientific field that studies the origins, early evolution, distribution, and future of life in the universe. Astrobiology considers the question of whether extraterrestrial life exists, and if it does, how humans can detect it.
Carl Edward Sagan was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space, the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the hypothesis, accepted since, that the high surface temperatures of Venus can be attributed to and calculated using the greenhouse effect.
Hypothetical types of biochemistry are forms of biochemistry agreed to be scientifically viable but not proven to exist at this time. The kinds of living organisms currently known on Earth all use carbon compounds for basic structural and metabolic functions, water as a solvent, and DNA or RNA to define and control their form. If life exists on other planets or moons it may be chemically similar, though it is also possible that there are organisms with quite different chemistries – for instance, involving other classes of carbon compounds, compounds of another element, or another solvent in place of water.
The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way Galaxy.
Extraterrestrial life is hypothetical life forms that may be living in places other than the planet Earth and which did not originate on Earth. Such life might range from simple prokaryotes to intelligent beings and even sapient beings, possibly bringing forth civilizations that might be far more advanced than humanity. The Drake equation speculates about the existence of sapient life elsewhere in the universe. The science of extraterrestrial life in all its forms is known as astrobiology.
The Fermi paradox is the conflict between the lack of clear, obvious evidence for extraterrestrial life and various high estimates for their existence.
The meaning of life, or the answer to the question: "What is the meaning of life?", pertains to the significance of living or existence in general. Many other related questions include: "Why are we here?", "What is life all about?", or "What is the purpose of existence?" There have been many proposed answers to these questions from many different cultural and ideological backgrounds. The search for life's meaning has produced much philosophical, scientific, theological, and metaphysical speculation throughout history. Different people and cultures believe different things for the answer to this question.
Sir Roger Penrose is a British mathematician, mathematical physicist, philosopher of science and Nobel Laureate in Physics. He is Emeritus Rouse Ball Professor of Mathematics at the University of Oxford, an emeritus fellow of Wadham College, Oxford, and an honorary fellow of St John's College, Cambridge, and University College London.
Reality is the sum or aggregate of all that is real or existent within a system, as opposed to that which is only imaginary. The term is also used to refer to the ontological status of things, indicating their existence. In physical terms, reality is the totality of a system, known and unknown. Philosophical questions about the nature of reality or existence or being are considered under the rubric of ontology, which is a major branch of metaphysics in the Western philosophical tradition. Ontological questions also feature in diverse branches of philosophy, including the philosophy of science, philosophy of religion, philosophy of mathematics, and philosophical logic. These include questions about whether only physical objects are real, whether reality is fundamentally immaterial, whether hypothetical unobservable entities posited by scientific theories exist, whether God exists, whether numbers and other abstract objects exist, and whether possible worlds exist.
Clifford Alan Pickover is an American author, editor, and columnist in the fields of science, mathematics, science fiction, innovation, and creativity. For many years, he was employed at the IBM Thomas J. Watson Research Center in Yorktown, New York where he was Editor-in-Chief of the IBM Journal of Research and Development. He has been granted more than 700 U.S. patents, is an elected Fellow for the Committee for Skeptical Inquiry, and is author of more than 50 books, translated into more than a dozen languages.
Communication with extraterrestrial intelligence or CETI, is a branch of the search for extraterrestrial intelligence (SETI) that focuses on composing and deciphering interstellar messages that theoretically could be understood by another technological civilization. The best-known CETI experiment of its kind was the 1974 Arecibo message composed by Frank Drake.
Planetary habitability is the measure of a planet's or a natural satellite's potential to develop and maintain environments hospitable to life. Life may be generated directly on a planet or satellite endogenously or be transferred to it from another body, through a hypothetical process known as panspermia. Environments do not need to contain life to be considered habitable nor are accepted habitable zones the only areas in which life might arise.
Gary Zukav is an American spiritual teacher and the author of four consecutive New York Times Best Sellers. Beginning in 1998, he appeared more than 30 times on The Oprah Winfrey Show to discuss transformation in human consciousness concepts presented in his book The Seat of the Soul. His first book, The Dancing Wu Li Masters (1979), won a U.S. National Book Award.
Stars outside of our Solar System and their planets have been featured as settings in works of fiction since at least the 1854 novel Star ou Psi de Cassiopée by C. I. Defontenay, which depicts aliens living in the planetary system around Psi Cassiopeiae.
Charles Cockell is a British astrobiologist who is professor of astrobiology in the School of Physics and Astronomy at the University of Edinburgh and co-director of the UK Centre for Astrobiology.
Steven J. Dick is an American astronomer, author, and historian of science most noted for his work in the field of astrobiology. Dick served as the Chief Historian for the National Aeronautics and Space Administration from 2003 to 2009 and as the Baruch S. Blumberg NASA/Library of Congress Chair in Astrobiology from 2013 to 2014. Before that, he was an astronomer and historian of science at the United States Naval Observatory in Washington, DC, from 1979 to 2003.
Dirk Schulze-Makuch is a professor at the Center for Astronomy and Astrophysics at the Technical University Berlin, Germany and Adjunct Professor at the School of Earth and Environmental Sciences Washington State University, Pullman, WA. He is best known for his publications on extraterrestrial life, being coauthor of five books on the topic: The Cosmic Zoo: Complex Life on Many Worlds (2017), A One Way Mission to Mars: Colonizing the Red Planet (2011), We Are Not Alone: Why We Have Already Found Extraterrestrial Life (2010), Cosmic Biology: How Life could Evolve on Other Worlds (2010), and Life in the Universe: Expectations and Constraints. In 2012 he published with David Darling Megacatastrophes! Nine Strange Ways the World Could End. In 2013 he published the second edition of his science fiction novel Alien Encounter. Together with Paul Davies he proposed in 2010 exploration of Mars by a one-way trip to the planet.
Eternal oblivion is the philosophical or religious concept of one's consciousness forever ceasing upon death. This concept is mostly associated with religious skepticism, secular humanism and atheism. According to most modern neuroscience theories of consciousness, the brain is the basis of subjective experience, agency, self-awareness, and awareness of the surrounding natural world. When brain death occurs, all brain function forever ceases.
