1. EXTRA TERRESTRIAL LIFE

4. EXTRATERRESTRIALS became a widespread phenomenon In the wake of the Roswell UFO incident in 1947, conspiracy theories on the presence of extraterrestrials became a widespread phenomenon in the United States during the 1940s and the beginning Space Age during the 1950s, accompanied by a surge of UFO reports. The term UFO itself was coined in 1952 in the context of the enormous popularity of the concept of "flying saucers" in the wake of the Kenneth Arnold UFO sighting in 1947.

5. The Roswell UFO incident took place in the U.S. in 1947, when an airborne object crashed on a ranch near Roswell, New Mexico, in June or July, 1947. Explanations of what took place are based on both official and unofficial communications. Although the crash is attributed to a U.S. military surveillance balloon by the U.S. government, the most famous explanation of what occurred is that the object was a spacecraft containing extraterrestrial life. Since the late 1970s, the Roswell incident has been the subject of much controversy, and conspiracy theories have arisen about the event.

7. Carl Sagan, David Grinspoon, Geoffrey A. Landisand Dirk Schulze-Makuch have put forward a hypothesis that microbes could exist in the stable cloud layers 50 km above the surface of venus The hypothesis is based on the premises of hospitable climates and chemical disequilibrium.

8. Life on Mars has been long speculated. Liquid water is widely thought to have existed on Mars in the past, and there may still be liquid water beneath the surface. By July 2008, laboratory tests aboard NASA's Phoenix Mars Lander had identified water in a soil sample. There is evidence that Mars had a warmer and wetter past: dried-up river beds, polar ice caps, volcanoes and minerals that form in the presence of water have all been found. present conditions on Mars may support life since lichens were found to successfully survive Martian conditions in the Mars Simulation Laboratory (MSL) maintained by the German Aerospace Center (DLR).

9. Carl Sagan and others in the 1960s and 1970s computed conditions for hypothetical amino acid-based macroscopic life in the atmosphere of Jupiter, based on observed conditions of this atmosphere. However, the conditions do not appear to permit the type of encapsulation thought necessary for molecular biochemistry, so life is thought to be unlikely. However, some of Jupiter's moons may have habitats to sustain life. Scientists have suggested that heated subsurface oceans of water may exist deep under the crusts of the three outer Galilean moons— Europa, Ganymede, and Callisto. Carl Sagan and others in the 1960s and 1970s computed conditions for hypothetical amino acid-based macroscopic life in the atmosphere of Jupiter, based on observed conditions of this atmosphere. However, the conditions do not appear to permit the type of encapsulation thought necessary for molecular biochemistry, so life is thought to be unlikely. However, some of Jupiter's moons may have habitats to sustain life. Scientists have suggested that heated subsurface oceans of water may exist deep under the crusts of the three outer Galilean moons— Europa, Ganymede, and Callisto.

11. While Saturn is itself considered inhospitable to life, the planet's natural satellites Titan and Enceladus have been speculated to possess possible habitats for life. Titan, the largest moon of Saturn, is the only known moon with a significant atmosphere. Data from the Cassini–Huygens mission refuted the hypothesis of a liquid hydrocarbon lakes in the polar regions—the first stable bodies of liquid discovered outside of Earth. Enceladus, a moon of Saturn, has some of the conditions for life including geothermal activity and water vapor as well as possible under-ice oceans heated by tidal effects. The Cassini probe detected carbon, hydrogen, nitrogen and oxygen—all key elements for supporting living organisms—during a fly-by through one of Enceladus's geysers spewing ice and gas in 2005.

12. Scientific search Direct search Indirect search

13. The scientific search for extraterrestrial life is being carried out both directly and indirectly. Directly – In this type of search the space shuttles, rovers or Landers are send to the place where the search has to be done. Indirectly – In these type of searches no rovers, Landers or space shuttles sort of thing is send instead laser signals are used for searching extra terrestrial life

14. The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research. President D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958. The new agency became operational on October 1, 1958.

15.  In February 2005, NASA scientists reported that they may have found some evidence of present life on Mars.  In August 2011, findings by NASA, based on studies of meteorites found on Earth, suggests DNA and RNA components (adenine, guanine and related organic molecules), building blocks for life as we know it, may be formed extraterrestrially in outer space.  In October 2011, scientists reported that cosmic dust contains complex organic matter ("amorphous organic solids with a mixed aromatic- aliphatic structure") that could be created naturally, and rapidly, by stars  In November 2011, NASA launched the Mars Science Laboratory (MSL) rover which is designed to search for past or present habitability on Mars using a variety of scientific instruments.

16. Unidentified flying object An unidentified flying object, or UFO, in its most general definition, is any apparent anomaly in the sky (or near or on the ground, but observed hovering, landing, or departing into the sky) that is not readily identifiable as any known object or phenomenon by visual observation and/or use of associated instrumentation such as radar. These anomalies were referred to popularly as “ flying saucers or flying discs The term "UFO" (or "UFOB") was officially created in 1953 by the United States Air Force (USAF) to replace the more popular terms because of the variety of shapes described other than "discs" or "saucers."

17. Project Sign was an official U.S. government study of unidentified flying objects (UFOs) undertaken by the United States Air Force and active for most of 1948. Project Sign's final report, published in early 1949, stated that while some UFOs appeared to represent actual aircraft there was not enough data to determine their origin. Project Magnet was an unidentified flying object (UFO) study programme established by the Canadian Department of Transport (DOT) on December 2, 1950 Smith eventually concluded that UFOs were probably extraterrestrial in origin and likely operated by manipulation of magnetism Project Grudge was a short-lived project by the U.S. Air Force to investigate unidentified flying objects (UFOs). Grudge succeeded Project Sign in February, 1949, and was then followed by Project Blue Book The project formally ended in December 1949, reporting that no evidence was found.

18. The search for extraterrestrial intelligence (SETI) is the collective name for a number of activities undertaken to search for intelligent extraterrestrial life. SETI project use scientific matter in this search. For example, electromagnetic radiation is monitored for signs of civilizations on other worlds. There are great challenges in searching the cosmos for signs of intelligent life, including their identification and interpretation. SETI projects use the best available scientific knowledge to conduct experiments, which has traditionally led to searches for electromagnetic radiations emitted by advanced technologies

19. CETI research has focused on four broad areas: mathematical languages, pictorial systems such as the Arecibo message, algorithmic communication systems (ACETI) and computational approaches to detecting and deciphering "natural" language communication Communication with extraterrestrial intelligence (CETI) is a branch of the search for extraterrestrial intelligence that focuses on composing and deciphering messages that could theoretically be understood by another technological civilization.