Astrobiology is a scientific field within the life and environmental sciences that studies the origins, early evolution, distribution, and future of life in the universe by investigating its deterministic conditions and contingent events. As a discipline, astrobiology is founded on the premise that life may exist beyond Earth.
Extraterrestrial life or alien life is life which does not originate from Earth. No extraterrestrial life has yet been conclusively detected. Such life might range from simple forms such as prokaryotes to intelligent 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 is known as astrobiology.
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 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 required an improbable combination of astrophysical and geological events and circumstances.
Planetary engineering is the development and application of technology for the purpose of influencing the environment of a planet. Planetary engineering encompasses a variety of methods such as terraforming, seeding, and geoengineering.
In astronomy and astrobiology, the habitable zone (HZ), or more precisely the circumstellar habitable zone (CHZ), is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure. The bounds of the HZ are based on Earth's position in the Solar System and the amount of radiant energy it receives from the Sun. Due to the importance of liquid water to Earth's biosphere, the nature of the HZ and the objects within it may be instrumental in determining the scope and distribution of planets capable of supporting Earth-like extraterrestrial life and intelligence.
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 (HZ) the only areas in which life might arise.
The New Frontiers program is a series of space exploration missions being conducted by NASA with the purpose of furthering the understanding of the Solar System. The program selects medium-class missions which can provide high science returns.
Heidi B. Hammel is a planetary astronomer who has extensively studied Neptune and Uranus. She was part of the team imaging Neptune from Voyager 2 in 1989. She led the team using the Hubble Space Telescope to view Shoemaker-Levy 9's impact with Jupiter in 1994. She has used the Hubble Space Telescope and the Keck Telescope to study Uranus and Neptune, discovering new information about dark spots, planetary storms and Uranus' rings. In 2002, she was selected as an interdisciplinary scientist for the James Webb Space Telescope.
David H. Grinspoon is an American astrobiologist. He is Senior Scientist at the Planetary Science Institute and was the former inaugural Baruch S. Blumberg NASA/Library of Congress Chair in Astrobiology for 2012–2013.
An Earth analog, also called an Earth analogue, Earth twin, or second Earth, is a planet or moon with environmental conditions similar to those found on Earth. The term Earth-like planet is also used, but this term may refer to any terrestrial planet.
David Morrison is an American astronomer, a senior scientist at the Solar System Exploration Research Virtual Institute, at NASA Ames Research Center in Mountain View, California. Morrison is the former director of the Carl Sagan Center for Study of Life in the Universe at the SETI Institute and of the NASA Lunar Science Institute. He is the past Director of Space at NASA Ames. Morrison is credited as a founder of the multi-disciplinary field of astrobiology. Morrison is best known for his work in risk assessment of near Earth objects such as asteroids and comets. Asteroid 2410 Morrison was named in his honor. Morrison is also known for his "Ask an Astrobiologist" series on NASA's website where he provides answers to questions submitted by the public. He has published 12 books and over 150 papers primarily on planetary science, astrobiology and near Earth objects.
The Nexus for Exoplanet System Science (NExSS) initiative is a National Aeronautics and Space Administration (NASA) virtual institute designed to foster interdisciplinary collaboration in the search for life on exoplanets. Led by the Ames Research Center, the NASA Exoplanet Science Institute, and the Goddard Institute for Space Studies, NExSS will help organize the search for life on exoplanets from participating research teams and acquire new knowledge about exoplanets and extrasolar planetary systems.
The Virtual Planetary Laboratory (VPL) is a virtual institute based at the University of Washington that studies how to detect exoplanetary habitability and their potential biosignatures. First formed in 2001, the VPL is part of the NASA Astrobiology Institute (NAI) and connects more than fifty researchers at twenty institutions together in an interdisciplinary effort. VPL is also part of the Nexus for Exoplanet System Science (NExSS) network, with principal investigator Victoria Meadows leading the NExSS VPL team.
The Carl Sagan Institute: Pale Blue Dot and Beyond was founded in 2014 at Cornell University in Ithaca, New York to further the search for habitable planets and moons in and outside the Solar System. It is focused on the characterization of exoplanets and the instruments to search for signs of life in the universe. The founder and current director of the institute is astronomer Lisa Kaltenegger.
A superhabitable planet is a hypothetical type of exoplanet or exomoon that may be better suited than Earth for the emergence and evolution of life. The concept was introduced in 2014 by René Heller and John Armstrong, who have criticized the language used in the search for habitable planets and proposed clarifications. According to Heller and Armstrong, knowing whether or not a planet is in its host star's habitable zone (HZ) is insufficient to determine its habitability: It is not clear why Earth should offer the most suitable physicochemical parameters to living organisms, as "planets could be non-Earth-like, yet offer more suitable conditions for the emergence and evolution of life than Earth did or does." While still assuming that life requires water, they hypothesize that Earth may not represent the optimal planetary habitability conditions for maximum biodiversity; in other words, they define a superhabitable world as a terrestrial planet or moon that could support more diverse flora and fauna than there are on Earth, as it would empirically show that its environment is more hospitable to life.
Rare Earth: Why Complex Life Is Uncommon in the Universe is a 2000 popular science book about xenobiology by Peter Ward, a geologist and evolutionary biologist, and Donald E. Brownlee, a cosmologist and astrobiologist. The book is the origin of the term 'Rare Earth Hypothesis' which denotes the central claim of the book: that complex life is rare in the universe.
Shawn D. Domagal-Goldman is a research space scientist at NASA Goddard Space Flight Center, who specializes in exoplanets, Archean geochemistry, planetary atmospheres, and astrobiology.
Athena Coustenis is an astrophysicist specializing in planetology. Dr. Coustenis, a French national, is director of research, Centre national de la recherche scientifique, at LESIA, at the Paris Observatory, Meudon. She is involved in several space mission projects for the European Space Agency (ESA) and for NASA. Her focus is on gas giant planets Saturn, Jupiter and their moons, and she is considered a foremost expert on Saturn's moon Titan.
Habitability of yellow dwarf systems defines the suitability for life of exoplanets belonging to yellow dwarf stars. These systems are the object of study among the scientific community because they are considered the most suitable for harboring living organisms, together with those belonging to K-type stars.
James Kasting, Origins 2011 congress