The Darwin Mission is a proposed European Space Agency (ESA) program designed to directly detect Earth-like planets orbiting nearby stars, and search for evidence of life on these planets. The European Space Agency ( ESA) established in 1975 is an intergovernmental organisation dedicated to the exploration of space, currently with 17 member EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 An extrasolar planet, or exoplanet, is a Planet beyond the Solar System, orbiting around other Stars As of September 2008 312 Extraterrestrial life is Life originating outside of the Earth. The launch date will be at or after 2015 according to the ESA. The current design envisions three free-flying space telescopes, each at least 3 meters in diameter, flying in formation as an astronomical interferometer. A space observatory is any instrument in Outer space which is used for observation of distant planets galaxies and other outer space objects An astronomical interferometer is an array of telescopes or mirror segments acting together to probe structures with higher resolution These telescopes will redirect the light to the main spacecraft which will contain the beam combiner, spectrographs and cameras for the interferometer array, and which will also act as a communications hub.
The space telescopes will observe in the infrared part of the electromagnetic spectrum. Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of The electromagnetic (EM spectrum is the range of all possible Electromagnetic radiation frequencies As well as studying extrasolar planets, the telescopes will probably have a general purpose imaging mode which will produce very high resolution (i. An extrasolar planet, or exoplanet, is a Planet beyond the Solar System, orbiting around other Stars As of September 2008 312 e. milliarcsecond) infrared images, allowing detailed study of a variety of astrophysical processes. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. The infrared region was chosen because in that part of the spectrum an Earth-like planet is only outshone by its star by a factor of a million; in the visible spectrum an Earth-like planet is outshone by its star by a factor of a billion.
The planet search would use a nulling interferometer configuration. A nuller is a tool used to block out a strong source so that fainter nearby signals can be observed In this system, phase shifts would be introduced into the three beams, so that light from the central star would suffer destructive interference and cancel itself out. However, light from any orbiting planets would not cancel out, as the planets are offset slightly from the position of the star. This would allow planets to be detected, despite the much brighter signal from the star.
For planet detection, the telescopes would operate in an imaging mode. To detect an Earth-like planet would require about 10 hours of observation in total, spread out over several months. Once a planet is detected, a more detailed study of its atmosphere would be made by taking an infrared spectrum of the planet. By analysing this spectrum, the chemistry of the atmosphere could be determined, and this could provide evidence for life on the planet. The presence of oxygen along with water vapor in the atmosphere would be evidence for life, as water vapor is extremely effective in reducing oxygen back to other gases. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the If nevertheless large amounts of oxygen exist in the atmosphere, it must be continually reproduced "artificially", i. e. via biological photosynthesis. Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. The presence of oxygen alone could not be seen as evidence. Numerical simulations showed that under proper conditions it is possible to build up an oxygen atmosphere via photolysis of carbon dioxide. Numerical analysis is the study of Algorithms for the problems of continuous mathematics (as distinguished from Discrete mathematics) Photodissociation, photolysis, or photodecomposition is a Chemical reaction in which a Chemical compound is broken down by Photons Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single
The interferometric version of NASA's Terrestrial Planet Finder mission is very similar in concept to Darwin, and also has very similar scientific aims. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program The Terrestrial Planet Finder ( TPF) was a plan by the National Aeronautics and Space Administration of the United States for a Telescope
Antoine Labeyrie has proposed a much larger space-based astronomical interferometer similar to Darwin, but with the individual telescopes positioned in a spherical arrangement and with an emphasis on interferometric imaging. Antoine Émile Henry Labeyrie (born 1943 is a French Astronomer. The spherical geometry reduces the amount of pathlength compensation required in re-pointing the interferometer array. This "Hypertelescope" project would be much more expensive and complex than the Darwin and TPF missions, involving many large free-flying spacecraft.
See also
External links
- DARWIN The official ESA homepage
- Darwin (Space IR Interferometry Project) on the Internet
- Interferometric Nulling at TNO
- The Darwin Breadboard Cryogenic Optical Delay Line
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