29 episodes

Part 29: Attempts at and methods of communication with intelligent aliens, as well as the implications this holds for our species.

These short videos were created in August 2007 by Dr. Christopher D. Impey, Professor of Astronomy at the University of Arizona, for his students. They cover a broad range of terms, concepts, and princples in astronomy and astrobiology. Dr. Impey is a University Distinguished Professor and Deputy Head of the Astonomy Department. All videos are intended solely for educational purposes and are licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. The full list of collections follows below:

01. Fundamentals of Science and Astronomy
02. Ancient Astronomy and Celestial Phenomena
03. Concepts and History of Astronomy and Physics
04. Chemistry and Physics
05. Quantum Theory and Radiation
06. Optics and Quantum Theory
07. Geology and Physics
08. Solar Neighborhood and Space Exploration
09. Outer Planets and Planetary Atmospheres
10. The Solar System
11. Interplanetary Bodies
12. Formation and Nature of Planetary Systems
13. Particle Physics and the Sun
14. Stars 1
15. Stars 2
16. Stars 3
17. Galactic Mass Distribtuion and Galaxy Structure
18. Galaxies
19. Galaxies 2
20. Galaxy Interaction and Motion
21. Deep Space and High-Energy Phenomena
22. The Big Bang, Inflation, and General Cosmology
23. The Big Bang, Inflation, and General Cosmology 2
24. Chemistry and Context for Life
25. Early Earth and Life Processes
26. Life on Earth
27. Life in the Universe
28. Interstellar Travel, SETI, and the Rarity of Life
29. Prospects of Nonhuman Intelligences

29. Prospects of Nonhuman Intelligences University of Arizona

    • Science
    • 3.8 • 5 Ratings

Part 29: Attempts at and methods of communication with intelligent aliens, as well as the implications this holds for our species.

These short videos were created in August 2007 by Dr. Christopher D. Impey, Professor of Astronomy at the University of Arizona, for his students. They cover a broad range of terms, concepts, and princples in astronomy and astrobiology. Dr. Impey is a University Distinguished Professor and Deputy Head of the Astonomy Department. All videos are intended solely for educational purposes and are licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. The full list of collections follows below:

01. Fundamentals of Science and Astronomy
02. Ancient Astronomy and Celestial Phenomena
03. Concepts and History of Astronomy and Physics
04. Chemistry and Physics
05. Quantum Theory and Radiation
06. Optics and Quantum Theory
07. Geology and Physics
08. Solar Neighborhood and Space Exploration
09. Outer Planets and Planetary Atmospheres
10. The Solar System
11. Interplanetary Bodies
12. Formation and Nature of Planetary Systems
13. Particle Physics and the Sun
14. Stars 1
15. Stars 2
16. Stars 3
17. Galactic Mass Distribtuion and Galaxy Structure
18. Galaxies
19. Galaxies 2
20. Galaxy Interaction and Motion
21. Deep Space and High-Energy Phenomena
22. The Big Bang, Inflation, and General Cosmology
23. The Big Bang, Inflation, and General Cosmology 2
24. Chemistry and Context for Life
25. Early Earth and Life Processes
26. Life on Earth
27. Life in the Universe
28. Interstellar Travel, SETI, and the Rarity of Life
29. Prospects of Nonhuman Intelligences

    • video
    Power and Radio Communication

    Power and Radio Communication

    Transcript: Why has the SETI strategy focused so heavily on radio waves for communication? There are simple reasons to do with fundamental physics. Radio photons are preferred over optical photons because they have low energy and so are less costly to produce in energetic terms, and they travel unimpeded through space, being unaffected by dust and gas. Also, there are regions of the electromagnetic spectrum where there are minimum amount of cosmic noise from other energy sources, and the radio part of the spectrum from one to a hundred gigahertz is just such a range. Also the sensitivity of our technology to radio detection is extraordinary. The Pioneer 10 satellite, currently at a distance of more than six billion miles from the Earth was detected by the Arecibo Radio Telescope when it was five billion miles from the Earth, yet it had the equivalent energy in its transmitter of a one Watt radio light bulb. The Arecibo dish itself, a thousand feet across, is the world’s largest radio telescope. In an interesting thought experiment, the Arecibo radio dish can not only listen but can send pulsed microwaves. If Arecibo-type radio technology existed anywhere else in the Milky Way galaxy, we could detect it if it were transmitting pulsed signals. Presumably the converse is true, and they could detect us. Thus radio waves, in principle, allow communication across the entire Milky Way galaxy.

    • 1 min
    • video
    Accidental Communication

    Accidental Communication

    Transcript: Why has the SETI strategy focused so heavily on radio waves for communication? There are simple reasons to do with fundamental physics. Radio photons are preferred over optical photons because they have low energy and so are less costly to produce in energetic terms, and they travel unimpeded through space, being unaffected by dust and gas. Also, there are regions of the electromagnetic spectrum where there are minimum amount of cosmic noise from other energy sources, and the radio part of the spectrum from one to a hundred gigahertz is just such a range. Also the sensitivity of our technology to radio detection is extraordinary. The Pioneer 10 satellite, currently at a distance of more than six billion miles from the Earth was detected by the Arecibo Radio Telescope when it was five billion miles from the Earth, yet it had the equivalent energy in its transmitter of a one Watt radio light bulb. The Arecibo dish itself, a thousand feet across, is the world’s largest radio telescope. In an interesting thought experiment, the Arecibo radio dish can not only listen but can send pulsed microwaves. If Arecibo-type radio technology existed anywhere else in the Milky Way galaxy, we could detect it if it were transmitting pulsed signals. Presumably the converse is true, and they could detect us. Thus radio waves, in principle, allow communication across the entire Milky Way galaxy.

    • 1 min
    • video
    Optical SETI

    Optical SETI

    Transcript: Although traditional SETI is conducted in terms of radio waves and their communication, it’s worth considering the possibility of optical SETI, using light waves to communicate through interstellar space. This has become possible due to current and modern technologies. For example, we have lasers which in a pulsed mode can outshine the Sun by a factor of ten thousand, if only for a microsecond or less. If such lasers existed on planets around nearby stars and were being pulsed in a meaningful way, these pulses would outshine the stars, and so the pulses would be visible from a very large distance. So in principle, optical intelligent signals could be seen. An even more sophisticated technique would involve a civilization aligning its signals with an intervening star or planet and using gravitational lensing to magnify, focus, and amplify the starlight, thus boosting the signal across large regions of space.

    • 1 min
    • video
    The Difficulty of Communication

    The Difficulty of Communication

    Transcript: Even if we accept the premise of SETI, that intelligent civilizations exist, and we accept the methodology of using radio waves to communicate across large distances of space and time, we are still left with a profound question. What should we say, and how should we say it? The idea of communication involves the idea of a message, but how do we encapsulate human intelligence and civilization in a message that can be coded and transmitted across regions of space? The danger, obviously, is anthropocentric thinking, couching our message too much in terms of human specific intelligence and culture. The specificity of culture and language should not be exaggerated. Remember that we share the planet with great apes like gorillas with whom we share ninety-nine percent of our DNA, yet we cannot communicate with them. We also have orcas and dolphins which may be intelligent, but we can communicate with them. So imagine now how difficult it might be to communicate with aliens of utterly different function and form.

    • 1 min
    • video
    Coding a Message

    Coding a Message

    Transcript: If we want to communicate through interstellar space with intelligent civilizations, we’ll have to decide on what message we want to send and how to code it. This is highly complex. How do we turn a subtle and complicated idea into a simple set of signals or bits of information? We have to reduce complexity to simple form, ones and zeroes, on and off, light and dark. This is a difficult process. We presume that a successful SETI signal will have to be pulsed to distinguish it from cosmic noise or other astrophysical sources of radiation. We presume that a successful signal that carries meaning will have to have a pattern. In other words it is neither random, nor completely regular. A completely regular periodic signal carries only one bit of information, the frequency of the pulsed source. These are the principles, but in practice it is likely to be far easier to decide that any signal that we might receive is nonrandom than to actually decode what it means. This is one of the fundamental lessons of cryptology.

    • 1 min
    • video
    The Arecibo Message

    The Arecibo Message

    Transcript: Rather than simply theorize or speculate, astronomers have been conducting modest experiments in interstellar communication. One of the first and most famous was done in 1974 using the Arecibo Radio Telescope, a thousand-foot radio dish in Puerto Rico. A pulsed set of messages was sent out sequentially to the M13 globular cluster. The sequence of signals consisted of one thousand six hundred and seventy-nine bits of information, that is on-off radio pulses. An intelligent civilization receiving such a message would presumably realize that sixteen seventy-nine has only two factors, seventy-three and twenty-three, suggesting hopefully two ways to arrange the information in a grid. One way produces a meaningless picture but the other way clearly indicates graphics if you also understand that you are to turn the bright or on signals into dark and the light into off, thus converting on-off signals into light and dark, or a picture. When shown this way, the Arecibo signal consists of a graphic of the solar system, of the Arecibo Radio Telescope, a little stick man, a schematic of the DNA molecule, and eight of the primary amino acids involved in life, but it’s just a schematic. There is no language involved and a civilization would have to understand what it means. It’s all very hypothetical anyway because M13 is twenty-five thousand lightyears away, so we will have to wait nearly fifty thousand years for a response if any is coming.

    • 1 min

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Interesting

Short, concise, informative, nicely done, and worthy of more time.

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