A related suggestion

A related suggestion is that aliens might broadcast pulsed and continuous laser signals in the optical, as well as infrared, spectrum;^[112] laser signals have the advantage of not "smearing" in the interstellar medium, and may prove more conducive to communication between the stars. While other communication techniques, including laser transmission and interstellar spaceflight,  HP KSB06105HA Laptop CPU Cooling Fan have been discussed seriously and may well be feasible, the measure of effectiveness is the amount of information communicated per unit cost. This results in radio transmission as the method of choice. Some have hypothesized that very advanced civilizations may create artificial black holes as an energy source or method of waste disposal. Dell Latitude E6510 Laptop CPU Cooling Fan Thus, they suggest that the observation of a black hole with a mass of less than 3.5 solar masses, the theoretical lower mass limit for a naturally occurring black hole, would be evidence of an alien civilization. Astronomers search for extrasolar planets that may be conducive to life, narrowing the search to terrestrial planets within the habitable zone.^[114][115] HP Pavilion dv6-2019er Laptop CPU Cooling Fan Current radiodetection methods have been inadequate for such a search, since the resolution afforded by recent technology is inadequate for a detailed study of extrasolar planetary objects. Future telescopes should be able to image planets around nearby stars, which may reveal the presence of life – either directly or through spectrography – and would reveal key information. HP Pavilion dv6-3126ea Laptop CPU Cooling Fan It has been argued that Alpha Centauri, the closest star system to Earth, may contain planets which could be capable of sustaining life.^[116] On April 24, 2007, scientists at the European Southern Observatory in La Silla, Chile said they had found the first Earth-like planet. HP 532613-001 Laptop CPU Cooling Fan The planet, known as Gliese 581 c, orbits within the habitable zone of its star Gliese 581, a red dwarf star which is 20.5 light years (194 trillion km) from the Earth. It was initially thought that this planet could contain liquid water, but recent computer simulations of the climate on Gliese 581 c by Werner von Bloh and his team at Germany's Institute for HP Pavilion dv6-3300ss Laptop CPU Cooling Fan Climate Impact Research suggest that carbon dioxide and methane in the atmosphere would create a runaway greenhouse effect. This would warm the planet well above the boiling point of water (100 degrees Celsius/212 degreesFahrenheit), thus dimming the hopes of finding life. As a result of greenhouse models, scientists are now turning their attention to Gliese 581 d, which lies just outside of the star's traditional habitable zone.^[117] IBM Lenovo Thinkpad W500 Series Laptop CPU Cooling Fan On May 29, 2007, the Associated Press released a report stating that scientists identified twenty-eight new extra-solar planetary bodies. One of these newly discovered planets is said to have many similarities to Neptune.^[118] In May 2011, researchers predicted that Gliese 581 d, not only exists in the "Goldilocks zone" where water can be present in liquid form, HP 646578-001 Laptop CPU Cooling Fan but is big enough to have a stable carbon dioxide atmosphere and "warm enough to have oceans, clouds, and rainfall," according to France's National Centre for Scientific Research.^[119] In December 2011, NASA confirmed that 600-light-year distant Kepler-22b, at 2.4 times the radius of Earth, is potentially the closest match to Earth in terms of both size and temperature.^[120][121] HP Pavilion dv5-1020et Laptop CPU Cooling Fan Since 1992, hundreds of planets around other stars ("extrasolar planets" or "exoplanets") in the Milky Way Galaxy have been discovered. As of February 18, 2014, the Extrasolar Planets Encyclopaedia identified 1077 extrasolar planets (in 814 planetary systems and 179 multiple planetary systems); the extrasolar planets range in size from that of terrestrial planets similar to Earth to that of gas giants larger than Jupiter.^[122HP Pavilion dv5030 Laptop CPU Cooling Fan ^] The number of observed exoplanets is expected to increase greatly in the coming years. Because the Kepler spacecraft must view three stellar transits by exoplanets before it identifies them as candidate planets, it has so far only been able to identify planets that orbit their star at a relatively quick rate. The mission is expected to continue until at least 2016, in which time many more exoplanet candidates are expected to be found.^[123] Compaq Presario CQ61-416EG Laptop CPU Cooling Fan Despite these successes, the transit method employed by the Kepler spacecraft requires that planetary orbits be at a small inclination to the line of sight of the observer. Due to this constraint, the probability of detecting a planet of Earth's size and orbital radius around a distant star is just 0.47%. Thus, the number of planets we are currently able to detect is only a small fraction of the total number of planets present within the galaxy. HP 532614-001 Laptop CPU Cooling Fan Criticism of the Drake equation follows mostly from the observation that the terms in the equation are entirely based on conjecture. Thus the equation cannot be used to draw firm conclusions of any kind.^[125] Although the Drake equation currently involves speculation about unmeasured parameters, it was not meant to be science, but intended as a way to stimulate dialogue on these topics. HP Pavilion dv5-1020et Laptop CPU Cooling Fan Then the focus becomes how to proceed experimentally. Indeed, Drake originally formulated the equation merely as an agenda for discussion at the Green Bank conference.^[126] Drake used the equation to estimate that there are approximately 10,000 planets in the Milky Way galaxy containing intelligent life with the possible capability of communicating with Earth.^[127]  HP 646578-001 Laptop CPU Cooling Fan Based on observations from the Hubble Space Telescope, there are at least 125 billion galaxies in the observable Universe. It is estimated that at least ten percent of all sun-like stars have a system of planets,^[128] i.e. there are 6.25×10¹⁸ stars with planets orbiting them in the observable Universe. Even if we assume that only one out of a billion of these stars have planets supporting life, HP Pavilion dv5-1020et Laptop CPU Cooling Fan HP Pavilion dv5030 Laptop CPU Cooling Fan there would be some 6.25×10⁹ (billion) life-supporting planetary systems in the observable Universe. The apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations is known as the Fermi paradox. In antiquity, it was common to assume a cosmos consisting of "many worlds" inhabited by intelligent, Compaq Presario CQ61-416EG Laptop CPU Cooling Fan non-human life-forms, but these "worlds" were mythological and not informed by the heliocentric understanding of the solar system, or the understanding of the Sun as one among countless stars.^[129] An example would be the fourteen Loka of Hindu cosmology, or theNine Worlds of Old Norse mythology, etc. The Sun and the Moon often appear as inhabited worlds in such contexts, or as vehicles (chariots or boats, etc.) driven by gods. HP 532614-001 Laptop CPU Cooling Fan The Japanese folk tale of The Tale of the Bamboo Cutter (10th century) is an example of a princess of the Moon people visiting Earth. Buddhist and Hindu beliefs of endlessly repeated cycles of life called Samsara have led to descriptions of multiple worlds in existence and their mutual contacts (Sanskrit word sampark (सम्पर्क) means "contact" as in Mahasamparka (महासम्पर्क) = "the great contact"). HP MCF-W13BM05 Laptop CPU Cooling Fan According to Buddhist and Hindu scriptures, there are numerous universes to facilitate the fulfillment of the separated desires of the numerous living entities. However, the purpose of such creations is to bring back the deluded souls to correct understanding about the purpose of life and achieve Nirvana. Aside from the numerous universes which are material, there is an unlimited number spirit worlds, HP Pavilion dv5-1174ca Laptop CPU Cooling Fan where the purified living entities live with perfect conception about life and ultimate reality. The spiritually aspiring saints and devotees, as well as thoughtful men of the material world, have been getting guidance and help from these purified living entities of the spiritual world from time immemorial.^{[citation needed]} The Jewish Talmud states that there are at least 18,000 other worlds, but provides little elaboration on the nature of those worlds, HP Pavilion dv7-3050ec Laptop CPU Cooling Fan or on whether they are physical or spiritual. Based on this, however, the 18th-century exposition "Sefer HaB'rit" posits that extraterrestrial creatures exist, and that some may well possess intelligence. It adds that humans should not expect creatures from another world to resemble earthly life any more than sea creatures resemble land animals.^[130][131] HP KSB06105HA Laptop CPU Cooling Fan According to Ahmadiyya a more direct reference from the Quran is presented by Mirza Tahir Ahmad as a proof that life on other planets may exist according to the Quran. In his book, Revelation, Rationality, Knowledge & Truth, he quotes verse 42:29 "And among His Signs is the creation of the heavens and the earth, and of whatever living creatures (da'bbah) He has spread forth in both..."; HP 646578-001 Laptop CPU Cooling Fan according to this verse there is life in heavens. According to the same verse "And He has the power to gather them together (jam-'i-him) when He will so please"; indicates the bringing together the life on Earth and the life elsewhere in the Universe. The verse does not specify the time or the place of this meeting but rather states that this event will most certainly come to pass whenever God so desires. HP 489126-001 Laptop CPU Cooling Fan It should be pointed out that the Arabic term Jam-i-him used to express the gathering event can imply either a physical encounter or a contact through communication.^[132] When Christianity spread throughout the West, the Ptolemaic system became very widely accepted, and although the Church never issued any formal pronouncement on the question of alien life at least tacitly, the idea was aberrant. DELL Inspiron E1405 Laptop CPU Cooling Fan In 1277, the Bishop of Paris, Étienne Tempier, did overturn Aristotle on one point: Godcould have created more than one world (given His omnipotence). Taking a further step, and arguing that aliens actually existed, remained rare. Notably, Cardinal Nicholas of Kues speculated about aliens on the Moon and Sun.^[133] William Vorilong also speculated about the existence of humans on alien worlds, DELL DFS541305MH0T Laptop CPU Cooling Fan but he came to the conclusion that God, although empowered to create them, would choose to not do so. There was a dramatic shift in thinking initiated by the invention of the telescope and the Copernican assault on geocentric cosmology. Once it became clear that the Earth was merely one planet amongst countless bodies in the universe, the theory of extraterrestrial life started to become a topic in the scientific community. HP G62-341NR Laptop CPU Cooling Fan The best known early-modern proponent of such ideas was the Italian philosopher Giordano Bruno, who argued in the 16th century for an infinite Universe in which every star is surrounded by its own planetary system. Bruno wrote that other worlds "have no less virtue nor a nature different to that of our earth" and, like Earth, "contain animals and inhabitants".^[134] HP Pavilion dv6648el Laptop CPU Cooling Fan In the early 17th century, the Czech astronomer Anton Maria Schyrleus of Rheita mused that "if Jupiter has (...) inhabitants (...) they must be larger and more beautiful than the inhabitants of the Earth, in proportion to the [characteristics] of the two spheres".^[135] In Baroque literature such as The Other World: The Societies and Governments of the Moon by Cyrano de Bergerac, HP Pavilion dv7-6151ed Laptop CPU Cooling Fan extraterrestrial societies are presented as humoristic or ironic parodies of earthly society. The didactic poet Henry Moretook up the classical theme of the Greek Democritus in "Democritus Platonissans, or an Essay Upon the Infinity of Worlds" (1647). In "The Creation: a Philosophical Poem in Seven Books" (1712), Sir Richard Blackmore observed: "We may pronounce each orb sustains a race / Of living things adapted to the place". Toshiba Satellite P100-386 Laptop CPU Cooling Fan With the new relative viewpoint that the Copernican revolution had wrought, he suggested "our world's sunne / Becomes a starre elsewhere". Fontanelle's "Conversations on the Plurality of Worlds" (translated into English in 1686) offered similar excursions on the possibility of extraterrestrial life, expanding, rather than denying, the creative sphere of a Maker.  HP G42-380LA Laptop CPU Cooling Fan The possibility of extraterrestrials remained a widespread speculation as scientific discovery accelerated. William Herschel, the discoverer of Uranus, was one of many 18th–19th-century astronomers convinced that the Solar System, and perhaps others, would be well populated by alien life. Other luminaries of the period who championed "cosmic pluralism" included Immanuel Kant and Benjamin Franklin.  HP G60-230us Laptop CPU Cooling Fan At the height of the Enlightenment, even the Sun and Moon were considered candidates for extraterrestrial inhabitants. Since the 1830s, Mormons have believed that God has created and will create many Earth-like planets on which humans live.^[136] HP KSB06105HA Laptop CPU Cooling Fan They believe that all of these people are children of God. Joseph Smith, the founder of The Church of Jesus Christ of Latter-day Saints, taught that God revealed this information to Moses and that the Creation account written by Moses corresponded only to "our" earth.^[137] There is no official doctrine relating to the location or commonality of these inhabited planets.^[138] SONY Vaio VPC-EB1E0E Laptop CPU Cooling FanSpeculation about life on Mars increased in the late 19th century, following telescopic observation by some observers of apparent Martian canals — which were however soon found to be optical illusions. Despite this, in 1895, American astronomer Percival Lowell published his book Mars, followed by Mars and its Canalsin 1906, proposing that the canals were the work of a long-gone civilization.^[139]  Compaq Presario CQ70-220EO Laptop CPU Cooling Fan This idea led British writer H. G. Wells to write The War of the Worlds in 1897, telling of an invasion by aliens from Mars who were fleeing the planet's desiccation. Spectroscopic analysis of Mars' atmosphere began in earnest in 1894, when U.S. astronomer William Wallace Campbell showed that neither water nor oxygen was present in the Martian atmosphere.^[140] HP Pavilion dv7-3060sb Laptop CPU Cooling Fan By 1909 better telescopes and the best perihelic opposition of Mars since 1877 conclusively put an end to the canal hypothesis. The science fiction genre, although not so named during the time, develops during the late 19th century. Jules Verne's Around the Moon (1870) features a discussion of the possibility of life on the Moon, but with the conclusion that it is barren. ACER Aspire 7720 Series Laptop CPU Cooling Fan Stories involving extraterrestrials are found in e.g. Garrett P. Serviss's Edison's Conquest of Mars (1897). The War of the Worlds by H. G. Wells was published in 1898 and stands at the beginning of the popular idea of the "Martian invasion" of Earth prominent in 20th-century pop culture. A radio drama version of Wells' novel broadcast in 1938 over the CBS Radio Network led to outrage because it supposedly suggested to many listeners that an actual alien invasion by Martians was in progress. SONY UDQF2PH52CF0 Laptop CPU Cooling Fan 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 sightingin 1947. Compaq Presario CQ61-216TU Laptop CPU Cooling Fan The Majestic 12 documents published in 1982 suggest that there was genuine interest in UFO conspiracy theories in the US government during the 1940s. The trend to assume that celestial bodies were populated almost by default was tempered as actual probes visited potential alien abodes in the Solar System beginning in the second half of the 20th century, Toshiba Satellite A215-S5802 Laptop CPU Cooling Fan and by the 1970s belief in UFOs had become part of the fringe beliefs associated with the paranormal, New Age, Earth mysteries, Forteana etc. A number of UFO religions developed during the surge in UFO belief during the 1950s to 1970s period, and some, such as Scientology (founded 1953) and Raëlism (founded 1974) remain active into the present. Toshiba Satellite A210-1BC Laptop CPU Cooling Fan The idea of "paleocontact", supposing that extraterrestrials ("ancient astronauts") have visited the Earth in the remote past and left traces in ancient cultures, appears in early-20th-century fiction such as The Call of Cthulhu (1926) and the idea came to be established as a notable aspect of the Ufology subculture in the wake of Erich von Däniken's Chariots of the Gods? (1968). DELL Inspiron 630m Laptop CPU Cooling Fan Alien abduction claims were widespread during the 1960s and 1970s in the United States. On the scientific side, the possibility of extraterrestrial life on the Moon was decisively ruled out by the 1960s, and during the 1970s it became clear that most of the other bodies of the Solar System do not harbour highly developed life, although the question of primitive life on bodies in the Solar System remains an open question. ACER Travelmate 4152nlci Laptop CPU Cooling Fan Carl Sagan, Bruce Murray, and Louis Friedman founded the U.S. Planetary Society, partly as a vehicle for SETI studies in 1980, and since the 1990s, systematic search for radio signals attributable to intelligent extraterrestrial life has been ongoing. In the early 1990s, NASA was set to join in on SETI research with a planned targeted search and all-sky survey. HP Pavilion dv6-3034tx Laptop CPU Cooling Fan However, Senator Richard Bryan of Nevada cut funding for the project, and no comparable search has taken place since. The failure so far of the SETI program to detect an intelligent radio signal after decades of effort, has at least partially dimmed the prevailing optimism of the beginning of the space ageHP G62-107SA Laptop CPU Cooling Fan . Notwithstanding, the belief in extraterrestrial beings continues to be voiced inpseudoscience, conspiracy theories, and in popular folklore, notably "Area 51" and legends. It has become a pop culture trope given less-than-serious treatment in popular entertainment with e.g. the ALF TV series (1986–1990), The X-Files (1993–2002), etc.  HP G62-455TX Laptop CPU Cooling Fan The SETI program is not the result of a continuous, dedicated search, but instead utilizes what resources and manpower it can, when it can. Furthermore, the SETI program only searches a limited range of frequencies at any one time.^[142] In the words of SETI's Frank Drake, "All we know for sure is that the sky is not littered with powerful microwave transmitters".^[143] HP 532617-001 Laptop CPU Cooling Fan Drake noted that it is entirely possible that advanced technology results in communication being carried out in some way other than conventional radio transmission. At the same time, the data returned by space probes, and giant strides in detection methods, have allowed science to begin delineating habitability criteria on other worlds, and to confirm that at least other planets are plentiful, though aliens remain a question mark. HP Pavilion dv6-1101au CPU Fan The Wow! signal, detected in 1977 by a SETI project, remains a subject of speculative debate. In 2000, geologist and paleontologist Peter Ward and astrobiologist Donald Brownlee published a book entitled Rare Earth: Why Complex Life is Uncommon in the Universe.^[144] In it, they discussed the Rare Earth hypothesis, in which they claim that Earth-like life is rare in the Universe, while microbial life is common. HP Pavilion dv7-3190ev CPU Fan Ward and Brownlee are open to the idea of evolution on other planets which is not based on essential Earth-like characteristics (such as DNA and carbon).The possible existence of primitive (microbial) life outside of Earth is much less controversial to mainstream scientists, although, at present, no direct evidence of such life has been found. Indirect evidence has been offered for the current existence of primitive life on Mars. HP Pavilion dv7-1157cl CPU Fan However, the conclusions that should be drawn from such evidence remain in debate. The Catholic Church has not made a formal ruling on the existence of extraterrestrials. However, writing in the Vatican newspaper, the astronomer, Father José Gabriel Funes, director of the Vatican Observatory near Rome, said in 2008 that intelligent beings created by God could exist in outer space.^[ HP COMPAQ NX9420 CPU Fan In September 2010, it was reported that the U.N. General Assembly had appointed Mazlan Othman as their official extraterrestrial liaison by the UK paper The Sunday Times.^[147] This claim was later refuted.^[148] Theoretical physicist Stephen Hawking in 2010 warned that humans should not try to contact alien life forms. He warned that aliens might pillage Earth for resources. "HP Mini 110-1110ET CPU Fan If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans", he said.^[149]Jared Diamond has expressed similar concerns.^[150] Scientists at NASA and Penn State University published a paper in April 2011 addressing the question "Would contact with extraterrestrials benefit or harm humanity?" The paper describes positive, negative and neutral scenarios.^[151] HP Pavilion dv7-1157cl CPU Fan In 2011, Richard Hoover, an astrobiologist at the U.S. Space Flight Center in Alabama, claimed that filaments and other structures in rare meteorites appear to be microscopic fossils of extraterrestrial beings that resemble cyanobacteria—a phylum of photosynthetic bacteria.^[152] On May 9, 2013, a congressional hearing by two U. S. House of Representatives subcommittees discussed "Exoplanet Discoveries: HP Pavilion dv6-3163eo CPU Fan Have We Found Other Earths?", prompted by the discovery of exoplanet Kepler-62f, along with Kepler-62e and Kepler-62c. A related special issue of the journal Science, published earlier, described the discovery of the exoplanets. For centuries people have speculated about the possibility of life on Mars due to the planet's proximity and similarity toEarth. HP Pavilion dv9740us CPU Fan Serious searches for evidence of life began in the 19th century, and continue via telescopic investigations and landed missions. While early work focused on phenomenology and bordered on fantasy, modern scientific inquiry has emphasized the search for water, chemical biosignatures in the soil and rocks at the planet's surface, and the search for biomarker gases in the atmosphere.^[1] ACER Aspire 4743 CPU Fan Mars is of particular interest for the study of the origins of life, because of its similarity to the early Earth. This is especially so as Mars has a cold climate and lacks plate tectonics or continental drift, and has remained almost unchanged since the end of the Hesperian period. At least two thirds of Mars' surface is more than 3.5 billion years old, and Mars may thus hold the best record of the prebiotic conditions leading to abiogenesis, even if life does not or has never existed there.^[2][3] It remains an open question whether life currently exists on Mars, or has existed there in the past, and fictional Martians have been a recurring feature of popular entertainment of the 20th and 21st centuries. HP Pavilion dv6-2170us CPU Fan On January 24, 2014, NASA reported that current studies on the planet Mars by the Curiosity and Opportunity rovers will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/orchemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.^[ Toshiba Satellite L675-S7018 CPU Fan The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.