Galactic habitable zoneIn astrobiology and planetary astrophysics, the galactic habitable zone is the region of a galaxy in which life might most likely develop. The concept of a galactic habitable zone analyzes various factors, such as metallicity (the presence of elements heavier than hydrogen and helium) and the rate and density of major catastrophes such as supernovae, and uses these to calculate which regions of a galaxy are more likely to form terrestrial planets, initially develop simple life, and provide a suitable environment for this life to evolve and advance.
Kepler space telescopeThe Kepler space telescope is a disused space telescope launched by NASA in 2009 to discover Earth-sized planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocentric orbit. The principal investigator was William J. Borucki. After nine and a half years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018.
Hypothetical types of biochemistryHypothetical 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.
Kepler-62fKepler-62f (also known by its Kepler Object of Interest designation KOI-701.04) is a super-Earth exoplanet orbiting within the habitable zone of the star Kepler-62, the outermost of five such planets discovered around the star by NASA's Kepler spacecraft. It is located about from Earth in the constellation of Lyra. Kepler-62f orbits its star at a distance of from its host star with an orbital period of roughly 267 days, and has a radius of around 1.41 times that of Earth.
Kepler-186fKepler-186f (also known by its Kepler object of interest designation KOI-571.05) is an exoplanet orbiting within the habitable zone of the red dwarf star Kepler-186, the outermost of five such planets discovered around the star by NASA's Kepler spacecraft. It is located about from Earth in the constellation of Cygnus. Kepler-186f orbits its star at a distance of about from its host star with an orbital period of roughly 130 days, and a mass and radius around 1.44 and 1.17 times that of Earth, respectively.
Carl SaganCarl Edward Sagan (ˈseɪɡən; ; November 9, 1934 December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, science communicator, author, and professor. His best known scientific contribution is his research on the possibility of extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation.
Kepler-442bKepler-442b (also known by its Kepler object of interest designation KOI-4742.01) is a confirmed near-Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the K-type main-sequence star Kepler-442, about from Earth in the constellation of Lyra. The planet orbits its host star at a distance of about with an orbital period of roughly 112.3 days. It has a mass of around 2.3 and has a radius of about 1.34 times that of Earth.
