History of Extraterrestrial Life Debate PDF

History of Extraterrestrial Life Debate NATS1525 Instructor: Parandis Tajbakhsh Summer 2024  Giovanni Schiaparelli By 1870s, most astronomers believed that with the exception of Mars, it is unlikely to nd life elsewhere in the sol...

History of Extraterrestrial Life Debate NATS1525 Instructor: Parandis Tajbakhsh Summer 2024  Giovanni Schiaparelli By 1870s, most astronomers believed that with the exception of Mars, it is unlikely to nd life elsewhere in the solar system. In 1877, Giovanni Schiaparelli, a respected Italian astronomer, started a series of observations of Mars and reported the sighting of canali. The year 1877 was special since, Mars was in Giovanni Schiaparelli (1835-1910) opposition, meaning that Mars and Sun appeared on opposite sides of the Earth. This event was especially important since Mars and In English translations, the word Earth came as close as 56 million km. “Canali” was translated to “Canals” rather than “Channels”. While “Channels” are formed in nature, “Canals” are man-made and thus gave the impression of structures made by Martians. fi  Giovanni Schiaparelli Many, including astronomer Edward Maunder and artist Nathaniel Green dismissed Canals as optical illusions but some took the idea very seriously and began follow up observations. Percival Lowell The Lowell Observatory Percival Lowell (1855-1916) One of the most ardent proponents of the idea of Martian Canals was the wealthy businessman, Percival Lowell. He personally paid for the construction of the Lowell observatory, still in use today.  Percival Lowell Lowell believed that Mars is covered by a system of Canals. Lowell Believed that an intelligent Martian civilization had built the canals to bring water from the polar caps towards the Martian equator. Mariner 4 pictures put the nal nail in What he was seeing was nothing but an optical the cof n of Martian canals illusion which had poisoned Schiaparelli’s vision as well. fi fi  Wallace and Life on Mars In 1907, Alfred Russell Wallace published his Is mars habitable? in response to Lowell’s claims. In this book, he argued that Mars has a very thin atmosphere and the temperature is much colder than what Lowell claims. Wallace rejected any claim of existence of complex life on Mars. Huge temperature variation on Mars from -150 C in winter polar caps to 35 C in equatorial summer is due to the thin atmosphere. From Lowell’s book, Mars and its canals But Mars remains one of the main targets of our search for life in the solar system.  Mars as We know It Today! We know that Mars had much warmer climate in the past and a large supply of water. id water in the past The planet however of Jan 24th!) minerals formed in hangradually 4 billionlost yeara ago signi cant amount of its atmosphere and its d water water.was probably present for https://www.youtube.com/watch?v=XI4k6jdqD0U fi  Mars as We know It Today! We know that Mars had much warmer climate in the past and a large supply of water. id water in the past The planet however of Jan 24th!) minerals formed in hangradually 4 billionlost yeara ago signi cant amount of its atmosphere and its d water water.was probably present for https://www.youtube.com/watch?v=XI4k6jdqD0U fi  Mars as We know It Today! We know that Mars had much warmer climate in the past and a large supply of water. id water in the past The planet however of Jan 24th!) minerals formed in hangradually 4 billionlost yeara ago signi cant amount of its atmosphere and its d water water.was probably present for https://www.youtube.com/watch?v=XI4k6jdqD0U fi  Mars as We know It Today! We know that Mars had much warmer climate in the past and a large supply of water. id water in the past The planet however of Jan 24th!) minerals formed in hangradually 4 billionlost yeara ago signi cant amount of its atmosphere and its d water water.was probably present for Terraforming is referred to a process which attempts to engineer Martian environment hospitable for terrestrial life. https://www.youtube.com/watch?v=XI4k6jdqD0U fi  Communicating with Extraterrestrials In the novel Micromegas, the inhabitants of different worlds easily established communication by learning human language. Interestingly enough, at the beginning of the 19th century, there appeared some proposals regarding the possibility of communication with extraterrestrials, especially Lunarians and Martians. Most of these methods rely on the use of Mathematics as a language or sending a light signal to other civilizations. Carl Friedrich Gauss (1778-1855) As a “misbehaving” One of these modes of communication is attributed to primary school kid Gauss Carl Friedrich Gauss, the prominent mathematician of found how to calculate the 19th century. 1+2+3+…+N = N(N+1)/2  Communicating with Extraterrestrials According to one version of story, Gauss, suggested that a giant gure in the shape of the “windmill” diagram be erected in Siberia (where wheat can be planted to depict this diagram). Apparently, his reasoning was that since the mathematics of the Selenites (Lunarians) is identical to ours, then they will Euclid’s proof of Pythagorean theorem recognize this image and will 2 2 2 know about their intelligent a +b =c neighbours. fi  Communicating with Extraterrestrials The Austrian astronomer, Joseph Johann von Littrow suggested that a huge square or circle canal be carved in the Sahara and lled with Kerosene. Once this is set ablaze, Selenites would recognize the existence of terrestrial intelligence. Joseph Johann von Littrow (1781-1840) The second half of the 19th century witnessed a world-wide application of the electrical telegraphy using Morse code. Reminder: Selenites = Lunarians = Inhabitants of the Moon! fi  Communicating with Extraterrestrials Francis Galton (famous statistician and cousin of Charles Darwin) suggested a combination of mirrors that would re ect enough sunlight to be detected by Martians. He even speculated about developing an interstellar language by a system of light signals. He provided an example of such a language, consisting of dots, dashes and lines, each communicated as a light Francis Galton (1822-1911) signal lasting 1.25, 2.5 and 5 seconds respectively. He showed how much mathematical information can be conveyed through such a system. He however anticipated the fact that extraterrestrials might employ bases other than base 10 (decimals) for their numerical system. fl Communicating with Extraterrestrials In 1901, Nikola Tesla suggested sending electric signals to Mars, convinced by the fact that a signi cant amount of power can lead to wireless communication. Tesla’s ambitious plan was inspired by an incident in his Colorado Spring lab in 1899. While investigating some electrical phenomena at Pike’s Peak, Tesla believed that he had spotted a weak signal that could be neither attributed to the Sun nor to the Earth and its atmospheric disturbances. Nikola Tesla (1856-1943) Tesla was con dent that he was the rst person to have picked up electrical signals from sent by Martians. fi fi fi  Search for Extraterrestrial Intelligence (SETI) Today the search for arti cially generated electromagnetic signals (electromagnetic waves generated not in nature but by potentially intelligent beings) is the basis for SETI or Search for Extraterrestrial Intelligence. These could be deliberate signals from another planetary system, or just the radio or television signals of an alien civilization that have travelled unhindered through space. SETI has started with the efforts of the Soviets in the 1960’s followed by the Americans in the 1970’s. Contact was a movie inspired by SETI So far, no signal has been detected. fi  Is Mathematics a Universal Language? The content of messages to communicate with ETI (extraterrestrial Intelligence), as suggested in the past and at present, heavily rely on the use of mathematics. But is mathematics a universal language? In this context, two schools of thought are considered: Are natural numbers, 1, Extreme Platonism 2, 3, 4, …. creation of difference comes down to answering this question human mind or do they Strict Formalism exist independent of human beings?  Is Mathematics a Universal Language? In this context, two schools of thought are considered: Extreme Platonists: Natural numbers and An intelligent all mathematical objects really exist in alien species can some hyper-world (world of perfect also discover objects) —-> Mathematics is discovered mathematics Strict Formalists: Mathematics is a kind of game played by speci c rules with the goal to solve every problem: Not all intelligent aliens 2 wings of a bird or 2 limbs or 2 cats might share it with us or exist but the natural number 2 does even understand it. not exist ——> Mathematics is the invention of human mind fi  Composing a Mathematical Message In composition of mathematical and scienti c messages, the belief is that all advanced civilizations share the same understanding of the science (recall what we mean by Science) and mathematics. This is best seen in the design of Pioneer plaque which was sent into space aboard pioneer 10, launched in 1972. As of 2023, Pioneer 10 is estimated to be at 139 AU from the Earth and is travelling roughly 2.5 AU each year. The last signal of Pioneer 10, was received in January 2003. fi  Composing a Mathematical Message In composition of mathematical and scienti c messages, the belief is that all advanced civilizations share the same understanding of the science (recall what we mean by Science) and mathematics. This is best seen in the design of Pioneer plaque which was sent into space aboard pioneer 10, launched in 1972. As of 2022, Pioneer 10 is estimated to be at 131 AU from the Earth and is travelling roughly 2.5 AU each year. The last signal of Pioneer 10, was received in January 2003. fi  Clicker Question What do you think this image, represent? (a) A simpli ed depiction of Earth in orbit around the Sun? (b) Proton and electron in the atom of hydrogen (c) pictorial representation of numbers 0, 1 and 2 (d) Relative position of the solar system with respect to the centre of the milky way fi  Clicker Question What do you think this image, represent? (a) A simpli ed depiction of Earth in orbit around the Sun (b) Proton and electron in the atom of hydrogen (c) pictorial representation of numbers 0, 1 and 2 (d) Relative position of the solar system with respect to the centre of the milky way fi  Clicker Question What is this part of the plaque showing? (a) All destinations where messages from Earth were sent out (b) Relative position of the brightest stars as seen on Earth at the time of launch of the spacecraft (c) our address in the milky way, speci ed in terms of the location of a number of pulsars in the milky way. (d) Ratio of the population of males to females in 15 different locations on Earth fi  Clicker Question What is this part of the plaque showing? (a) All destinations where messages from Earth were sent out (b) Relative position of the brightest stars as seen on Earth at the time of launch of the spacecraft (c) Our address in the milky way, speci ed in terms of the location of a number of pulsars in the milky way. (d) Ratio of the population of males to females in 15 different locations on Earth fi  Clicker Question In your opinion, what feature in this image is the hardest one to be understood by an alien civilization? (a) Hydrogen atom (b) Image of the man and woman (c) Location of the milky way (d) the arrow indicating the origin of the spacecraft  Clicker Question In your opinion, what feature in this image is the hardest one to be understood by an alien civilization? (a) Hydrogen atom (b) Image of the man and woman (c) Location of the milky way (d) the arrow indicating the origin of the spacecraft  Pioneer Plaque A unit of length is provided using the atomic properties of Hydrogen. This unit of length is 21 cm. This is based on the assumption that an advanced extraterrestrial civilization has the same knowledge of Quantum mechanics as we do. Numbers in the plaque are represented by a binary code, consisting of 1s and 0s. 1 is shown with I and 0 is shown with -. The general idea behind the design of Pioneer Plaque is that any advanced extraterrestrial Looks familiar? civilization understands universe using the language of mathematics.  Pioneer Plaque A unit of length is provided using the atomic properties of Hydrogen. This unit of length is 21 cm. This is based on the assumption that an advanced extraterrestrial civilization has the same knowledge of Quantum mechanics as we do. Numbers in the plaque are represented by a binary code, consisting of 1s and 0s. 1 is shown with I and 0 is shown with -. The general idea behind the design of Pioneer Plaque is that any advanced extraterrestrial Looks familiar? civilization understands universe using the language of mathematics.  Pioneer Plaque A unit of length is provided using the atomic properties of Hydrogen. This unit of length is 21 cm. This is based on the assumption that an advanced extraterrestrial civilization has the same knowledge of Quantum mechanics as we do. Numbers in the plaque are represented by a binary code, consisting of 1s and 0s. 1 is shown with I and 0 is shown with -. The general idea behind the design of Pioneer Plaque is that any advanced extraterrestrial Looks familiar? civilization understands universe using the language of mathematics. Pioneer Plaque The radial pattern at the left is our address in the Milky Way, speci ed in terms of the location of a number of pulsars in our galaxy. The binary numbers on each ray is the period of the pulsar in terms of the frequency associated with the 21-cm line. The length of the ray is the distance between the Sun and that pulsar in units of the 21-cm line. Pulsar are stellar corpse otherwise known as rotating neutron stars that send out beams of electromagnetic radiation in precise time intervals. They act much like the light houses and the beam can only be observed when it is sent out towards our direction! fi  Pioneer Plaque At the bottom of the plaque, there is a code showing our location in the solar system. The distance of each planet from the sun is given in terms of binary numbers using the distance of mercury as the unit distance.  Pioneer Plaque At the bottomThe attempt of the to communicate plaque, there is with ET is a product of humankind’s inborn curiosity. Yet, not everyone agrees on a code showing our location in the the potential risks of communication: solar system. Risk of detection (this is to some extent calculable) The distance ofRisk each planet (this of contact fromis unknown and possibly can never the sun is givenbeinknown) terms of binary numbers using the distance of Can we ever agree whether we must send out mercury as the unit distance. messages or not?