Terraforming or terraformation ("Earth-shaping") is the hypothetical process of deliberately modifying the atmosphere, temperature, surface topography or ecology of a planet, moon, or other body to be similar to the environment of Earth to make it habitable for humans to live on.
In astronomy, a conjunction occurs when two astronomical objects or spacecraft appear to be close to each other in the sky. This means they have either the same right ascension or the same ecliptic longitude, usually as observed from Earth.
A doomsday device is a hypothetical construction — usually a weapon or weapons system — which could destroy all life on a planet, particularly Earth, or destroy the planet itself, bringing "doomsday", a term used for the end of planet Earth. Most hypothetical constructions rely on hydrogen bombs being made arbitrarily large, assuming there are no concerns about delivering them to a target or that they can be "salted" with materials designed to create long-lasting and hazardous fallout.
In astronomy, a transit is the passage of a celestial body directly between a larger body and the observer. As viewed from a particular vantage point, the transiting body appears to move across the face of the larger body, covering a small portion of it.
The Late Great Planet Earth is a 1970 book by Hal Lindsey, with contributions by Carole C. Carlson, first published by Zondervan. The New York Times declared it to be the bestselling "nonfiction" book of the 1970s. The book was first featured on a primetime television special featuring Hal Lindsey in 1974 and 1975 with an audience of 17 million and produced by Alan Hauge of GMT Productions. It was adapted by Rolf Forsberg and Robert Amram into a 1978 film narrated by Orson Welles and released by Pacific International Enterprises.
The Hill sphere is a common model for the calculation of a gravitational sphere of influence. It is the most commonly used model to calculate the spatial extent of gravitational influence of an astronomical body (m) in which it dominates over the gravitational influence of other bodies, particularly a primary (M). It is sometimes confused with other models of gravitational influence, such as the Laplace sphere or being called the Roche sphere, the latter causing confusion with the Roche limit. It was defined by the American astronomer George William Hill, based on the work of the French astronomer Édouard Roche.
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, both faculty members at the University of Washington.
The planet Venus has been used as a setting in fiction since before the 19th century. Its opaque cloud cover gave science fiction writers free rein to speculate on conditions at its surface—a "cosmic Rorschach test", in the words of science fiction author Stephen L. Gillett. The planet was often depicted as warmer than Earth but still habitable by humans. Depictions of Venus as a lush, verdant paradise, an oceanic planet, or fetid swampland, often inhabited by dinosaur-like beasts or other monsters, became common in early pulp science fiction, particularly between the 1930s and 1950s. Some other stories portrayed it as a desert, or invented more exotic settings. The absence of a common vision resulted in Venus not developing a coherent fictional mythology, in contrast to the image of Mars in fiction.
The Nibiru cataclysm is a supposed disastrous encounter between Earth and a large planetary object that certain groups believed would take place in the early 21st century. Believers in this doomsday event usually refer to this object as Nibiru or Planet X. The idea was first put forward in 1995 by Nancy Lieder, founder of the website ZetaTalk. Lieder claims she is a contactee with the ability to receive messages from extraterrestrials from the Zeta Reticuli star system through an implant in her brain. She states that she was chosen to warn mankind that the object would sweep through the inner Solar System in May 2003 causing Earth to undergo a physical pole shift that would destroy most of humanity.
John R. Gribbin is a British science writer, an astrophysicist, and a visiting fellow in astronomy at the University of Sussex. His writings include quantum physics, human evolution, climate change, global warming, the origins of the universe, and biographies of famous scientists. He also writes science fiction.
Worlds in Collision is a book by Immanuel Velikovsky published in 1950. The book postulates that around the 15th century BC, the planet Venus was ejected from Jupiter as a comet or comet-like object and passed near Earth. The object allegedly changed Earth's orbit and axis, causing innumerable catastrophes that are mentioned in early mythologies and religions from around the world. The book has been heavily criticized as a work of pseudoscience and catastrophism, and many of its claims are completely rejected by the established scientific community as they are not supported by any available evidence.
Black holes, objects whose gravity is so strong that nothing—including light—can escape them, have been depicted in fiction since at least the pulp era of science fiction, before the term black hole was coined. A common portrayal at the time was of black holes as hazards to spacefarers, a motif that has also recurred in later works. The concept of black holes became popular in science and fiction alike in the 1960s. Authors quickly seized upon the relativistic effect of gravitational time dilation, whereby time passes more slowly closer to a black hole due to its immense gravitational field. Black holes also became a popular means of space travel in science fiction, especially when the notion of wormholes emerged as a relatively plausible way to achieve faster-than-light travel. In this concept, a black hole is connected to its theoretical opposite, a so-called white hole, and as such acts as a gateway to another point in space which might be very distant from the point of entry. More exotically, the point of emergence is occasionally portrayed as another point in time—thus enabling time travel—or even an entirely different universe.
The 2012 phenomenon was a range of eschatological beliefs that cataclysmic or transformative events would occur on or around 21 December 2012. This date was regarded as the end-date of a 5,126-year-long cycle in the Mesoamerican Long Count calendar, and festivities took place on 21 December 2012 to commemorate the event in the countries that were part of the Maya civilization, with main events at Chichén Itzá in Mexico and Tikal in Guatemala.
Comets have appeared in works of fiction since at least the 1830s. They primarily appear in science fiction as literal objects, but also make occasional symbolical appearances in other genres. In keeping with their traditional cultural associations as omens, they often threaten destruction to Earth. This commonly comes in the form of looming impact events, and occasionally through more novel means such as affecting Earth's atmosphere in different ways. In other stories, humans seek out and visit comets for purposes of research or resource extraction. Comets are inhabited by various forms of life ranging from microbes to vampires in different depictions, and are themselves living beings in some stories.
In astronomy, a syzygy is a roughly straight-line configuration of three or more celestial bodies in a gravitational system.
This is complete list of works by American science fiction and fantasy author Fred Saberhagen.
This is an incomplete list of works by American space opera and science fiction author Frederik Pohl, including co-authored works.
Comets is an anthology of science fiction short stories edited by Isaac Asimov, Martin H. Greenberg and Charles G. Waugh as the fourth volume in their Isaac Asimov's Wonderful Worlds of Science Fiction series. It was first published in paperback by Signet/New American Library in February 1986.
Syzygy is a 1981 novel by Frederik Pohl. It was inspired by the non-fiction work, The Jupiter Effect by John Gribbin and Stephen Plagemann, in which an alignment of the planets of the Solar System in March 1982 was predicted as possibly causing disasters on Earth, including a large earthquake in California, by its effect on the solar wind. The prediction did not come to pass, the theory was debunked, and Gribbin himself announced that he regretted publishing it.
