The Fermi paradox is the discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high likelihood of its existence. Those affirming the paradox generally conclude that if the conditions required for life to arise from non-living matter are as permissive as the available evidence on Earth indicates, then extraterrestrial life would be sufficiently common such that it would be implausible for it not to have been detected yet.
The Omphalos hypothesis is one attempt to reconcile the scientific evidence that the Earth is billions of years old with a literal interpretation of the Genesis creation narrative, which implies that the Earth is only a few thousand years old. It is based on the religious belief that the universe was created by a divine being, within the past six to ten thousand years, and that the presence of objective, verifiable evidence that the universe is older than approximately ten millennia is due to the creator introducing false evidence that makes the universe appear significantly older.
Alien invasion or space invasion is a common feature in science fiction stories and films, in which extraterrestrial lifeforms invade Earth to exterminate and supplant human life, enslave it, harvest people for food, steal the planet's resources, or destroy the planet altogether. It can be considered as a science-fiction subgenre of the invasion literature, expanded by H. G. Wells's seminal alien invasion novel The War of the Worlds, and is a type of 'first contact' science fiction.
Robert James Sawyer is a Canadian and American science fiction writer. He has had 25 novels published and his short fiction has appeared in Analog Science Fiction and Fact, Amazing Stories, On Spec, Nature, and numerous anthologies. He has won many writing awards, including the best-novel Nebula Award (1995), the best-novel Hugo Award (2003), the John W. Campbell Memorial Award (2006), the Robert A. Heinlein Award (2017), and more Aurora Awards than anyone else in history.
Ancient astronauts refers to a pseudoscientific set of beliefs that hold that intelligent extraterrestrial beings visited Earth and made contact with humans in antiquity and prehistoric times. Proponents of the theory suggest that this contact influenced the development of modern cultures, technologies, religions, and human biology. A common position is that deities from most religions are extraterrestrial in origin, and that advanced technologies brought to Earth by ancient astronauts were interpreted as evidence of divine status by early humans.
Young Earth creationism (YEC) is a form of creationism which holds as a central tenet that the Earth and its lifeforms were created by supernatural acts of the Abrahamic God between about 6,000 and 10,000 years ago, contradicting established scientific data for the age of Earth putting it at around 4.54 billion years. In its most widespread version, YEC is based on a religious belief in the inerrancy of certain literal interpretations of the Book of Genesis. Its primary adherents are Christians and Jews who believe that God created the Earth in six literal days.
The concept of self-replicating spacecraft, as envisioned by mathematician John von Neumann, has been described by futurists and has been discussed across a wide breadth of hard science fiction novels and stories. Self-replicating probes are sometimes referred to as von Neumann probes. Self-replicating spacecraft would in some ways either mimic or echo the features of living organisms or viruses.
The zoo hypothesis speculates on the assumed behavior and existence of technologically advanced extraterrestrial life and the reasons they refrain from contacting Earth. It is one of many theoretical explanations for the Fermi paradox. The hypothesis states that extraterrestrial life intentionally avoids communication with Earth to allow for natural evolution and sociocultural development, and avoiding interplanetary contamination, similar to people observing animals at a zoo. The hypothesis seeks to explain the apparent absence of extraterrestrial life despite its generally accepted plausibility and hence the reasonable expectation of its existence.
The Great Filter is the idea that, in the development of life from the earliest stages of abiogenesis to reaching the highest levels of development on the Kardashev scale, there is a barrier to development that makes detectable extraterrestrial life exceedingly rare. The Great Filter is one possible resolution of the Fermi paradox. The main conclusion of the Great Filter is that there is an inverse correlation between the probability that other life could evolve to the present stage in which humanity is, and the chances of humanity to survive in the future.
Jonathan David Sarfati is a young Earth creationist who writes articles for Creation Ministries International (CMI), a non-profit Christian apologetics ministry. Sarfati has a PhD in chemistry, and was New Zealand national chess champion in 1987 and 1988.
First contact is a common theme in science fiction about the first meeting between humans and extraterrestrial life, or of any sentient species' first encounter with another one, given they are from different planets or natural satellites. It is closely related to the anthropological idea of first contact.
"The Star" is a science fiction short story by English writer Arthur C. Clarke. It appeared in the science fiction magazine Infinity Science Fiction in 1955 and won the Hugo Award in 1956. It is collected in Clarke's 1958 book of short stories The Other Side of the Sky, and it was reprinted in the January 1965 issue of Short Story International as the lead-off story.
Fossil Hunter is a novel written by Canadian science fiction author Robert J. Sawyer. The sequel to Far-Seer, it is the second book of the Quintaglio Ascension Trilogy. The book depicts an Earth-like world on a moon which orbits a gas giant, inhabited by a species of highly evolved, sentient Tyrannosaurs called Quintaglios, among various other creatures from the late cretaceous period, imported to this moon by aliens 65 million years prior to the story. Originally published in 1993 by Ace Science Fiction, it won the Homer award for "Best Novel" during its initial release date. It was reissued in 2005 by Tor Books.
Supernovae, extremely powerful explosions of stars, have been featured in works of fiction since at least the early 1900s. The idea that the Sun could explode in this manner has served as the basis for many stories about disaster striking Earth, though it is now recognized that this cannot actually happen. Recurring themes in these stories include anticipating the inevitable destruction while being helpless and evacuating the planet, sometimes with the assistance of helpful aliens. The destruction of Earth in this manner occasionally serves as backstory explaining why humanity has started colonizing the cosmos. Another recurring scenario is radiation from more distant supernovae threatening Earth. Besides humans, alien civilizations are also occasionally subject to the dangers of supernovae. Supernovae are induced intentionally in several works, typically for use as weapons but sometimes for more peaceful purposes, and naturally occurring supernovae are likewise exploited in some stories.
Robert J. (Bob) Schadewald was an author, researcher, and former president of the National Center for Science Education (NCSE). An internationally recognized expert on pseudoscience, Schadewald penned numerous articles on creationism, perpetual motion, flat earthism, and other pseudoscience for such magazines as Science 80, Technology Illustrated, Smithsonian, and Science Digest.
Donald Ross Prothero is an American geologist, paleontologist, and author who specializes in mammalian paleontology and magnetostratigraphy, a technique to date rock layers of the Cenozoic era and its use to date the climate changes which occurred 30–40 million years ago. He is the author or editor of more than 30 books and over 300 scientific papers, including at least 5 geology textbooks.
The following outline is provided as an overview of and topical guide to extraterrestrial life:
The dark forest hypothesis is the conjecture that many alien civilizations exist throughout the universe, but they are both silent and hostile, maintaining their undetectability for fear of being destroyed by another hostile and undetected civilization. It is one of many possible explanations of the Fermi paradox, which contrasts the lack of contact with alien life with the potential for such contact. The hypothesis derives its name from Liu Cixin's 2008 novel The Dark Forest, although the concept predates the novel.
The Oppenheimer Alternative is a 2020 science fiction alternate history novel by Canadian writer Robert J. Sawyer. It was first published in June 2020 in Canada by Red Deer Press, and in the United States by CAEZIK SF & Fantasy, 75 years after the atomic bombings of Hiroshima and Nagasaki in 1945. The novel was nominated for The Canadian Science Fiction and Fantasy Association's 2021 Aurora Award for Best Novel.
