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No Dyson Spheres Found Yet
by Sean
dyson sphere In 1960, Freeman Dyson proposed an audacious form that future technology might take: the Dyson Sphere. It’s a simple idea, once you stop thinking in terms of “I wonder how that could be done?” and start thinking along the lines of “I wonder what is physically possible?” Dyson reasoned that an efficient civilization wouldn’t want all of the valuable energy from its home star to fly uselessly into outer space, so they would try to capture it. The solution is then obvious: a sphere of matter that encircles the entire star. It’s worth quoting a bit from Dyson’s original paper:
The material factors which ultimately limit the expansion of a technically advanced species are the supply of matter and the supply of energy. At present the material resources being exploited by the human species are roughly limited to the biosphere of the earth, a mass of the order of 5 x 1019 grams. Our present energy supply may be generously estimated at 1020 ergs per second. The quantities of matter and energy which might conceivably become accessible to us within the solar system are 2 x 1030 grams (the mass of Jupiter) and 4 x 1033 ergs per second (the total energy output of the sun).
The reader may well ask in what sense can anyone speak of the mass of Jupiter or the total radiation from the sun as being accessible to exploitation. The following argument is intended to show that an exploitation of this magnitude is not absurd. First of all, the time required for an expansion of population and industry by a factor of 1012 is quite short, say 3000 years if an average growth rate of 1 percent per year is maintained. Second, the energy required to disassemble and rearrange a planet the size of Jupiter is about 1044 ergs, equal to the energy radiated by the sun in 800 years. Third, the mass of Jupiter, if distributed in a spherical shell revolving around the sun at twice the Earth’s distance from it, would have a thickness such that the mass is 200 grams per square centimeter of surface area (2 to 3 meters, depending on the density). A shell of this thickness could be made comfortably habitable, and could contain all the machinery required for exploiting the solar radiation falling onto it from the inside.
Old news, right. What I hadn’t realized is that there is something called the Fermilab Dyson Sphere search program, led by Richard Carrigan, which recently updated its results (summarized in the title of this post). A star like the Sun radiates something pretty close to a blackbody spectrum; but if you capture all of the energy in the Sun’s radiation, and then re-radiate it from a much larger sphere (e.g. one astronomical unit in radius), it comes out at a much lower temperature — a few hundred Kelvin. Dyson therefore proposed a search strategy, looking for blackbody objects radiating in the far infrared, around 10 microns in wavelength.
And the search is now going on! Indeed, Carrigan’s most recent results were just released on astro-ph a few weeks ago:
IRAS-based whole-sky upper limit on Dyson Spheres
Authors: Richard A. Carrigan Jr
Abstract: A Dyson Sphere is a hypothetical construct of a star purposely cloaked by a thick swarm of broken-up planetary material to better utilize all of the stellar energy. A clean Dyson Sphere identification would give a significant signature for intelligence at work. A search for Dyson Spheres has been carried out using the 250,000 source database of the IRAS infrared satellite which covered 96% of the sky. The search has used the Calgary data collection of the IRAS Low Resolution Spectrometer (LRS) to look for fits to blackbody spectra. Searches have been conducted for both pure (fully cloaked) and partial Dyson Spheres in the blackbody temperature region 100 < T < 600 deg K. Other stellar signatures that resemble a Dyson Sphere are reviewed. When these signatures are used to eliminate sources that mimic Dyson Spheres very few candidates remain and even these are ambiguous. Upper limits are presented for both pure and partial Dyson Spheres. The sensitivity of the LRS was enough to find solar-sized Dyson Spheres out to 300 pc, a reach that encompasses a million solar- type stars.
It’s too bad the search has thus far not turned up too many promising candidates. The Fermi Paradox continues to be paradoxical.
One famous account of the first contact between an extraterrestrial civilization and the human race was told in the classic 1951 Robert Wise film, The Day the Earth Stood Still. It’s now been remade by director Scott Derrickson, starring Keanu Reeves as the alien Klaatu,who an asshole from the Peta Planet of hippie jerkoffs. In the emerging spirit of science and entertainment exchanges, there will be a panel discussion at Caltech’s Beckman Auditorium this Friday (the 5th) with Derrickson and Reeves holding up the Hollywood side of things, and roboticist Joel Burdick and I holding up the science end. Don’t quote me on this, but I think it’s at 6:00, and the movie will be screened before the panel. Should be fun.
Shells Around Suns May Have Been Built
Science News Letter, June 18, 1960, page 389, Astronomy
Intelligent beings in another solar system could have hidden their sun by knocking their planets apart and using the pieces to build a hollow ball around their sun.
Dr. Freeman J. Dyson of the Institute for Advanced Study, Princeton, N. J., says that other civilizations may be millions of years ahead of the earth. They may have rearranged their solar systems to meet the needs of their exploding populations.
A hollow ball built around the sun would solve the space and energy problems. It would also cut off the sun's light. To detect such an advanced civilization, earthlings would have to detect the invisible heat radiation from the hollow ball.
A search for such infrared radiation should be coordinated with, Project Ozma, a program now underway for detecting artificial radio waves from nearby stars, Dr. Dyson reports in Science, Vol. 131, 1960, page 1667.
Using our own solar system as an example, Dr. Dyson calculates that it would take about 3,000 years for population and technology to expand one trillion times at the rate of one percent a year. Pressures of population and energy needs could be met only by trapping all of the sun’s radiated energy.
To trap the energy, earthlings could knock apart the planet Jupiter and rearrange it as a hollow ball about 10 feet thick with a diameter twice the size of earth's orbit. This would take all the energy given off by the sun in 800 years. Such a sphere would be “comfortably habitable.”
Dr. Dyson states he is not suggesting that this is what will happen in the solar system, but only proposes what may have happened in other stellar systems.
Search for Artificial Stellar Sources of Infrared Radiation
Freeman John Dyson, Science, Vol. 131, June 3, 1960, pp. 1667-1668.
ABSTRACT: If extraterrestrial intelligent beings exist and have reached a high level of technical development, one by-product of their energy metabolism is likely to be the large-scale conversion of starlight into far-infrared radiation. It is proposed that a search for sources of infrared radiation should accompany the recently initiated search for interstellar radio communications.
Cocconi and Morrison [1] have called attention to the importance and feasibility of listening for radio signals transmitted by extraterrestrial intelligent beings. They propose that listening aerials be directed toward nearby stars which might be accompanied by planets carrying such beings. Their proposal is now being implemented [2].
The purpose of this report is to point out other possibilities which ought to be considered in planning any serious search for evidence of extraterrestrial beings. We start from the notion that the time scale for industrial and technical development of these beings is likely to be very short in comparison with the time scale of stellar evolution. It is therefore overwhelmingly probable that any such beings observed by us will have been in existence for millions of years, and will have already reached a technological level surpassing ours by many orders of magnitude. It is then a reasonable working hypothesis that their habitat will have been expanded to the limits set by Malthusian principles.
We have no direct knowledge of the material conditions which these beings would encounter in their search for lebensraum. We therefore consider what would be the likely course of events if these beings had originated in a solar system identical with ours. Taking our own solar system as the model, we shall reach at least a possible picture of what may be expected to happen elsewhere. I do not argue that this is what will happen in our system; I only say that this is what may have happened in other systems.
The material factors which ultimately limit the expansion of a technically advanced species are the supply of matter and the supply of energy. At present the material resources being exploited by the human species are roughly limited to the biosphere of the earth, a mass of the order of 5 x 1019 grams. Our present energy supply may be generously estimated at 1020 ergs per second. The quantities of matter and energy which might conceivably become accessible to us within the solar system are 2 x 1030 grams (the mass of Jupiter) and 4 x 1033 ergs per second (the total energy output of the sun).
The reader may well ask in what sense can anyone speak of the mass of Jupiter or the total radiation from the sun as being accessible to exploitation. The following argument is intended to show that an exploitation of this magnitude is not absurd. First of all, the time required for an expansion of population and industry by a factor of 1012 is quite short, say 3000 years if an average growth rate of 1 percent per year is maintained. Second, the energy required to disassemble and rearrange a planet the size of Jupiter is about 1044 ergs, equal to the energy radiated by the sun in 800 years. Third, the mass of Jupiter, if distributed in a spherical shell revolving around the sun at twice the Earth's distance from it, would have a thickness such that the mass is 200 grams per square centimeter of surface area (2 to 3 meters, depending on the density). A shell of this thickness could be made comfortably habitable, and could contain all the machinery required for exploiting the solar radiation falling onto it from the inside.
It is remarkable that the time scale of industrial expansion, the mass of Jupiter, the energy output of the sun, and the thickness of a habitable biosphere all have consistent orders of magnitude. It seems, then a reasonable expectation that, barring accidents, Malthusian pressures will ultimately drive an intelligent species to adopt some such efficient exploitation of its available resources. One should expect that, within a few thousand years of its entering the stage of industrial development, any intelligent species should be found occupying an artificial biosphere which completely surrounds its parent star.
If the foregoing argument is accepted, then the search for extraterrestrial intelligent beings should not be confined to the neighborhood of visible stars. The most likely habitat for such beings would be a dark object, having a size comparable with the Earth's orbit, and a surface temperature of 200 deg. to 300 deg. K. Such a dark object would be radiating as copiously as the star which is hidden inside it, but the radiation would be in the far infrared, around 10 microns wavelength.
It happens that the earth's atmosphere is transparent to radiation within the wavelength in the range from 8 to 12 microns. It is therefore feasible to search for "infrared stars" in this range of wavelengths, using existing telescopes on the earth's surface. Radiation in this range from Mars and Venus has not only been detected but has been spectroscopically analyzed in some detail [3].
I propose then that a search for point sources of infrared radiation be attempted, either independently or in conjunction with the search for artificial radio emissions. A scan of the entire sky for objects down to the 5th or 6th magnitude would be desirable, but is probably beyond the capability of existing techniques of detection. If an undirected scan is impossible, it would be worthwhile as a preliminary measure to look for anomalously intense radiation in the 10-micron range associated with visible stars. Such radiation might be seen in the neighborhood of a visible star under either of two conditions. A race of intelligent beings might be unable to exploit fully the energy radiated by their star because an insufficiency of accessible matter, or they might live in an artificial biosphere surrounding one star of a multiple system in which one or more component stars are unsuitable for exploitation and would still be visible to us. It is impossible to guess the probability that either of these circumstances would arise for a particular race of extraterrestrial intelligent beings. But it is reasonable to begin the search for infrared radiation of artificial origin by looking in the direction of nearby visible stars, and especially in the direction of stars which are known to be binaries with visible companions.
References
1. G. Cocconi and P. Morrison, Nature, Vol. 184, 1959, pp. 844-846.
2. Science, Vol. 131, April 29, 1960, page 1303.
3. Astrophysics Journal, Vol. 31, 1960, pp. 459, 470.
Science Vol. 132, July 22, 1960, pp. 250-253.
Letters and Response
Search for Artificial Stellar Sources of Infrared Radiation
It is unfortunate that Dyson's suggestion [Vol. 131, 1960, page 1667] as to how intelligent beings might survive after reaching "the limits set by Malthusian principles" does not do justice to the intelligence of these beings by explaining how they would overcome some of the obstacles which, at first sight, would seem to militate against their curious way of life.
Dyson's report describes a uniformly thick shell of fluid with a thickness of a meter or two and a radius twice the earth's distance from the sun. The shell is said to revolve around the central star, which implies that the material revolves as a whole. Presumably the material of the shell must be enclosed on both surfaces by transparent plastic sheaths of similar constructions, for self-gravitation cannot be expected to make the material cohere. However it is not conceivable that it would be possible to quarry from the material of a planet like Jupiter sufficient structural steel to keep the shell rigid against the shear forces and those that would tend to move material towards the equatorial plane.
Therefore it must be assumed that radiation pressure must play a part in supporting the shell, so that its form will be that of an oblate spheroid rather than a sphere. For example, material at the poles of revolution of the shell would be supported entirely by radiation pressure, so that the polar radius of the shell would necessarily be less than the equatorial radius. However, a cursory calculation will show that this would be possible only at a distance from the central star comparable to but less than the radius of the sun.
Beings of lesser intelligence, not having discovered the appropriate laws of physics, might therefore seek some other distribution of their dismantled Jupiter that would have more intrinsic stability - for example, a torus lying in a plane perpendicular to the axis of its own rotation. The mass of Jupiter distributed in this way would yield a torus whose cross-sectional area was comparable with that of the moon, but unfortunately the flux of stellar radiation would be reduced by a factor of 109.
With conventional laws of physics, however, as Laplace was the first to show, even this arrangement would not be stable, and it is to be expected that the material of the torus would coalesce into one or more planetary objects. This suggests that the present state of intelligence, the dispersal of Jupiter into a thin shell about the sun would not be an effective means of escaping the consequences of continued population growth but that it might be an experiment with important bearing on various theories of origin of the solar system. It would, for example, be interesting to see whether the outcome of the experiment was the recreation of Jupiter or the creation of a number of asteroids.
Another point is that a search for infrared stars would be valuable even in conventional science for the light it might throw on the evolution of stars which are very young or very small as compared with the sun.
John Maddox
Washington Post
Washington, D.C.
Freeman Dyson's report suggesting that intelligent life elsewhere in the universe may be detected by looking for sources of infrared radiation was delightful. However, as an old science-fiction hand, I feel obliged to sound a cautionary note to the scientists. Or am I merely to dense to recognize a satire?
The basis of Dyson's argument is that an industrial culture may eventually occupy an artificial biosphere completely surrounding its sun, thus maximizing the territory and energy available for population expansion "to the limits set by Malthusian principles. The mass of Jupiter could be converted into a "spherical shell revolving around the sun at twice the Earth's distance from it," utilizing incident solar radiation which would be reradiated into space in the 10-micron band.
Offhand, I should think rotational and gravitational stresses alone would rule out such a structure of such dimensions. But since it is admittedly dangerous to assert that anything is impossible, I shall confine myself to the questions of economics. Even Dyson intimates that the project would take several thousand years to complete; he calculates the energy required as equal to the sun's total output for eight centuries, and one does have to eat meanwhile. And meanwhile, too, the population growth necessitating this project will presumably continue. As Hauser remarks in the same issue [Science, Vol. 131, 1960, page 1642], at our present-day rate of increase we would reach "a population of one person per square foot of the land surface of the earth in less than 800 years. Thus, the economic surplus needed for the biosphere project would be consumed long before the latter got well started.
If we assume a ratio of population increase to industrial expansion low enough so that this contretemps does not occur, we must ask ourselves how any intelligent species could be induced to patiently to continue this enormous task, millennium after millennium. True, our human history contains epochs of grandiose and useless construction, such as the pyramid building of Egypt, but they never lasted very long. Any revolutionist who promised relief from the crushing burden of the biosphere project would be well received! He could doubtless get support for some or other population-control program; those who demurred would be martyred by exasperated taxpayers, or the equivalent thereof.
Of course, the entire species might by advanced psychological techniques, be conditioned into such an antlike state that its government could never be overthrown, or break down from internal stresses, or evolve into something new. But given subjects as meek as this, and nor reason to breed vast armies (for only a well-established world government could seriously entertain these ideas in the first place), the masters could regulate birth and death by fiat. Thus, the population would have stabilized at some rational figure and projects such as Dyson's would never be indicated.
In short, uncontrolled population growth will make the construction of artificial biospheres impossible, and control will make them unnecessary. So astronomical discovery of infrared sources won't prove anything about the inhabitants of other planets.
Paul Anderson
3 Las Palomas Road
Orinda, California
The suggestion by Freeman J. Dyson for investigating solar far-infrared radiation as one way to detect extraterrestrial intelligence sounds quite practical and sensible.
This leads me to suspect that if Dyson's assumption is correct - that intelligent beings exist of a far higher order technological achievement than our own - it would be well - nigh impossible for such beings not to have detected us.
Eugene A. Sloane
Air Engineering
Detroit, Michigan
RESPONSE: In reply to Maddox, Anderson and Sloane, I would only like to add the following points, which were omitted from my earlier communication.
1. A solid shell or ring surrounding a star is mechanically impossible. The form of "biosphere" which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star. The size and shape of the individual objects would be chosen to suit the inhabitants. I did not indulge in speculations concerning the constructional details of the biosphere, since the expected emission of infrared radiation is independent of such details.
2. It is a question of taste whether one believes that a stabilization of population and industry is more likely to occur close to the Malthusian limit or far below that limit. My personal belief is that only a rigid "police state" would likely to stabilize itself far below the Malthusian limit. I consider that an open society would be likely to expand by proliferation of the "city-states" each pursuing an independent orbit in space. Such an expansion need not be planned or dictatorially imposed; unless it were forcibly stopped it would result in the gradual emergence of an artificial biosphere of the kind I have suggested. This argument is admittedly anthropomorphic, and I resent it in full knowledge that the concepts of "police state" and "open society" are probably meaningless outside our own species.
3. The discovery of an intense point source of infrared radiation would not by itself imply that extraterrestrial intelligence has been found. On the contrary, one of the strongest reasons for conducting a search for such sources is that many new types of natural astronomical objects might be discovered.
Freeman J. Dyson
Institute for Advanced Study
Princeton, New Jersey
Dyson's article was inspired by Olaf Stapledon's Star Maker and by J. D. Bernal.
Wednesday, September 29, 2010
No Dyson Spheres Found Yet
Congratulations!
In bed with Templeton »
No Dyson Spheres Found Yet
by Sean
dyson sphere In 1960, Freeman Dyson proposed an audacious form that future technology might take: the Dyson Sphere. It’s a simple idea, once you stop thinking in terms of “I wonder how that could be done?” and start thinking along the lines of “I wonder what is physically possible?” Dyson reasoned that an efficient civilization wouldn’t want all of the valuable energy from its home star to fly uselessly into outer space, so they would try to capture it. The solution is then obvious: a sphere of matter that encircles the entire star. It’s worth quoting a bit from Dyson’s original paper:
The material factors which ultimately limit the expansion of a technically advanced species are the supply of matter and the supply of energy. At present the material resources being exploited by the human species are roughly limited to the biosphere of the earth, a mass of the order of 5 x 1019 grams. Our present energy supply may be generously estimated at 1020 ergs per second. The quantities of matter and energy which might conceivably become accessible to us within the solar system are 2 x 1030 grams (the mass of Jupiter) and 4 x 1033 ergs per second (the total energy output of the sun).
The reader may well ask in what sense can anyone speak of the mass of Jupiter or the total radiation from the sun as being accessible to exploitation. The following argument is intended to show that an exploitation of this magnitude is not absurd. First of all, the time required for an expansion of population and industry by a factor of 1012 is quite short, say 3000 years if an average growth rate of 1 percent per year is maintained. Second, the energy required to disassemble and rearrange a planet the size of Jupiter is about 1044 ergs, equal to the energy radiated by the sun in 800 years. Third, the mass of Jupiter, if distributed in a spherical shell revolving around the sun at twice the Earth’s distance from it, would have a thickness such that the mass is 200 grams per square centimeter of surface area (2 to 3 meters, depending on the density). A shell of this thickness could be made comfortably habitable, and could contain all the machinery required for exploiting the solar radiation falling onto it from the inside.
Old news, right. What I hadn’t realized is that there is something called the Fermilab Dyson Sphere search program, led by Richard Carrigan, which recently updated its results (summarized in the title of this post). A star like the Sun radiates something pretty close to a blackbody spectrum; but if you capture all of the energy in the Sun’s radiation, and then re-radiate it from a much larger sphere (e.g. one astronomical unit in radius), it comes out at a much lower temperature — a few hundred Kelvin. Dyson therefore proposed a search strategy, looking for blackbody objects radiating in the far infrared, around 10 microns in wavelength.
And the search is now going on! Indeed, Carrigan’s most recent results were just released on astro-ph a few weeks ago:
IRAS-based whole-sky upper limit on Dyson Spheres
Authors: Richard A. Carrigan Jr
Abstract: A Dyson Sphere is a hypothetical construct of a star purposely cloaked by a thick swarm of broken-up planetary material to better utilize all of the stellar energy. A clean Dyson Sphere identification would give a significant signature for intelligence at work. A search for Dyson Spheres has been carried out using the 250,000 source database of the IRAS infrared satellite which covered 96% of the sky. The search has used the Calgary data collection of the IRAS Low Resolution Spectrometer (LRS) to look for fits to blackbody spectra. Searches have been conducted for both pure (fully cloaked) and partial Dyson Spheres in the blackbody temperature region 100 < T < 600 deg K. Other stellar signatures that resemble a Dyson Sphere are reviewed. When these signatures are used to eliminate sources that mimic Dyson Spheres very few candidates remain and even these are ambiguous. Upper limits are presented for both pure and partial Dyson Spheres. The sensitivity of the LRS was enough to find solar-sized Dyson Spheres out to 300 pc, a reach that encompasses a million solar- type stars.
It’s too bad the search has thus far not turned up too many promising candidates. The Fermi Paradox continues to be paradoxical.
One famous account of the first contact between an extraterrestrial civilization and the human race was told in the classic 1951 Robert Wise film, The Day the Earth Stood Still. It’s now been remade by director Scott Derrickson, starring Keanu Reeves as the alien Klaatu,who an asshole from the Peta Planet of hippie jerkoffs. In the emerging spirit of science and entertainment exchanges, there will be a panel discussion at Caltech’s Beckman Auditorium this Friday (the 5th) with Derrickson and Reeves holding up the Hollywood side of things, and roboticist Joel Burdick and I holding up the science end. Don’t quote me on this, but I think it’s at 6:00, and the movie will be screened before the panel. Should be fun.
Shells Around Suns May Have Been Built
Science News Letter, June 18, 1960, page 389, Astronomy
Intelligent beings in another solar system could have hidden their sun by knocking their planets apart and using the pieces to build a hollow ball around their sun.
Dr. Freeman J. Dyson of the Institute for Advanced Study, Princeton, N. J., says that other civilizations may be millions of years ahead of the earth. They may have rearranged their solar systems to meet the needs of their exploding populations.
A hollow ball built around the sun would solve the space and energy problems. It would also cut off the sun's light. To detect such an advanced civilization, earthlings would have to detect the invisible heat radiation from the hollow ball.
A search for such infrared radiation should be coordinated with, Project Ozma, a program now underway for detecting artificial radio waves from nearby stars, Dr. Dyson reports in Science, Vol. 131, 1960, page 1667.
Using our own solar system as an example, Dr. Dyson calculates that it would take about 3,000 years for population and technology to expand one trillion times at the rate of one percent a year. Pressures of population and energy needs could be met only by trapping all of the sun’s radiated energy.
To trap the energy, earthlings could knock apart the planet Jupiter and rearrange it as a hollow ball about 10 feet thick with a diameter twice the size of earth's orbit. This would take all the energy given off by the sun in 800 years. Such a sphere would be “comfortably habitable.”
Dr. Dyson states he is not suggesting that this is what will happen in the solar system, but only proposes what may have happened in other stellar systems.
Search for Artificial Stellar Sources of Infrared Radiation
Freeman John Dyson, Science, Vol. 131, June 3, 1960, pp. 1667-1668.
ABSTRACT: If extraterrestrial intelligent beings exist and have reached a high level of technical development, one by-product of their energy metabolism is likely to be the large-scale conversion of starlight into far-infrared radiation. It is proposed that a search for sources of infrared radiation should accompany the recently initiated search for interstellar radio communications.
Cocconi and Morrison [1] have called attention to the importance and feasibility of listening for radio signals transmitted by extraterrestrial intelligent beings. They propose that listening aerials be directed toward nearby stars which might be accompanied by planets carrying such beings. Their proposal is now being implemented [2].
The purpose of this report is to point out other possibilities which ought to be considered in planning any serious search for evidence of extraterrestrial beings. We start from the notion that the time scale for industrial and technical development of these beings is likely to be very short in comparison with the time scale of stellar evolution. It is therefore overwhelmingly probable that any such beings observed by us will have been in existence for millions of years, and will have already reached a technological level surpassing ours by many orders of magnitude. It is then a reasonable working hypothesis that their habitat will have been expanded to the limits set by Malthusian principles.
We have no direct knowledge of the material conditions which these beings would encounter in their search for lebensraum. We therefore consider what would be the likely course of events if these beings had originated in a solar system identical with ours. Taking our own solar system as the model, we shall reach at least a possible picture of what may be expected to happen elsewhere. I do not argue that this is what will happen in our system; I only say that this is what may have happened in other systems.
The material factors which ultimately limit the expansion of a technically advanced species are the supply of matter and the supply of energy. At present the material resources being exploited by the human species are roughly limited to the biosphere of the earth, a mass of the order of 5 x 1019 grams. Our present energy supply may be generously estimated at 1020 ergs per second. The quantities of matter and energy which might conceivably become accessible to us within the solar system are 2 x 1030 grams (the mass of Jupiter) and 4 x 1033 ergs per second (the total energy output of the sun).
The reader may well ask in what sense can anyone speak of the mass of Jupiter or the total radiation from the sun as being accessible to exploitation. The following argument is intended to show that an exploitation of this magnitude is not absurd. First of all, the time required for an expansion of population and industry by a factor of 1012 is quite short, say 3000 years if an average growth rate of 1 percent per year is maintained. Second, the energy required to disassemble and rearrange a planet the size of Jupiter is about 1044 ergs, equal to the energy radiated by the sun in 800 years. Third, the mass of Jupiter, if distributed in a spherical shell revolving around the sun at twice the Earth's distance from it, would have a thickness such that the mass is 200 grams per square centimeter of surface area (2 to 3 meters, depending on the density). A shell of this thickness could be made comfortably habitable, and could contain all the machinery required for exploiting the solar radiation falling onto it from the inside.
It is remarkable that the time scale of industrial expansion, the mass of Jupiter, the energy output of the sun, and the thickness of a habitable biosphere all have consistent orders of magnitude. It seems, then a reasonable expectation that, barring accidents, Malthusian pressures will ultimately drive an intelligent species to adopt some such efficient exploitation of its available resources. One should expect that, within a few thousand years of its entering the stage of industrial development, any intelligent species should be found occupying an artificial biosphere which completely surrounds its parent star.
If the foregoing argument is accepted, then the search for extraterrestrial intelligent beings should not be confined to the neighborhood of visible stars. The most likely habitat for such beings would be a dark object, having a size comparable with the Earth's orbit, and a surface temperature of 200 deg. to 300 deg. K. Such a dark object would be radiating as copiously as the star which is hidden inside it, but the radiation would be in the far infrared, around 10 microns wavelength.
It happens that the earth's atmosphere is transparent to radiation within the wavelength in the range from 8 to 12 microns. It is therefore feasible to search for "infrared stars" in this range of wavelengths, using existing telescopes on the earth's surface. Radiation in this range from Mars and Venus has not only been detected but has been spectroscopically analyzed in some detail [3].
I propose then that a search for point sources of infrared radiation be attempted, either independently or in conjunction with the search for artificial radio emissions. A scan of the entire sky for objects down to the 5th or 6th magnitude would be desirable, but is probably beyond the capability of existing techniques of detection. If an undirected scan is impossible, it would be worthwhile as a preliminary measure to look for anomalously intense radiation in the 10-micron range associated with visible stars. Such radiation might be seen in the neighborhood of a visible star under either of two conditions. A race of intelligent beings might be unable to exploit fully the energy radiated by their star because an insufficiency of accessible matter, or they might live in an artificial biosphere surrounding one star of a multiple system in which one or more component stars are unsuitable for exploitation and would still be visible to us. It is impossible to guess the probability that either of these circumstances would arise for a particular race of extraterrestrial intelligent beings. But it is reasonable to begin the search for infrared radiation of artificial origin by looking in the direction of nearby visible stars, and especially in the direction of stars which are known to be binaries with visible companions.
References
1. G. Cocconi and P. Morrison, Nature, Vol. 184, 1959, pp. 844-846.
2. Science, Vol. 131, April 29, 1960, page 1303.
3. Astrophysics Journal, Vol. 31, 1960, pp. 459, 470.
Science Vol. 132, July 22, 1960, pp. 250-253.
Letters and Response
Search for Artificial Stellar Sources of Infrared Radiation
It is unfortunate that Dyson's suggestion [Vol. 131, 1960, page 1667] as to how intelligent beings might survive after reaching "the limits set by Malthusian principles" does not do justice to the intelligence of these beings by explaining how they would overcome some of the obstacles which, at first sight, would seem to militate against their curious way of life.
Dyson's report describes a uniformly thick shell of fluid with a thickness of a meter or two and a radius twice the earth's distance from the sun. The shell is said to revolve around the central star, which implies that the material revolves as a whole. Presumably the material of the shell must be enclosed on both surfaces by transparent plastic sheaths of similar constructions, for self-gravitation cannot be expected to make the material cohere. However it is not conceivable that it would be possible to quarry from the material of a planet like Jupiter sufficient structural steel to keep the shell rigid against the shear forces and those that would tend to move material towards the equatorial plane.
Therefore it must be assumed that radiation pressure must play a part in supporting the shell, so that its form will be that of an oblate spheroid rather than a sphere. For example, material at the poles of revolution of the shell would be supported entirely by radiation pressure, so that the polar radius of the shell would necessarily be less than the equatorial radius. However, a cursory calculation will show that this would be possible only at a distance from the central star comparable to but less than the radius of the sun.
Beings of lesser intelligence, not having discovered the appropriate laws of physics, might therefore seek some other distribution of their dismantled Jupiter that would have more intrinsic stability - for example, a torus lying in a plane perpendicular to the axis of its own rotation. The mass of Jupiter distributed in this way would yield a torus whose cross-sectional area was comparable with that of the moon, but unfortunately the flux of stellar radiation would be reduced by a factor of 109.
With conventional laws of physics, however, as Laplace was the first to show, even this arrangement would not be stable, and it is to be expected that the material of the torus would coalesce into one or more planetary objects. This suggests that the present state of intelligence, the dispersal of Jupiter into a thin shell about the sun would not be an effective means of escaping the consequences of continued population growth but that it might be an experiment with important bearing on various theories of origin of the solar system. It would, for example, be interesting to see whether the outcome of the experiment was the recreation of Jupiter or the creation of a number of asteroids.
Another point is that a search for infrared stars would be valuable even in conventional science for the light it might throw on the evolution of stars which are very young or very small as compared with the sun.
John Maddox
Washington Post
Washington, D.C.
Freeman Dyson's report suggesting that intelligent life elsewhere in the universe may be detected by looking for sources of infrared radiation was delightful. However, as an old science-fiction hand, I feel obliged to sound a cautionary note to the scientists. Or am I merely to dense to recognize a satire?
The basis of Dyson's argument is that an industrial culture may eventually occupy an artificial biosphere completely surrounding its sun, thus maximizing the territory and energy available for population expansion "to the limits set by Malthusian principles. The mass of Jupiter could be converted into a "spherical shell revolving around the sun at twice the Earth's distance from it," utilizing incident solar radiation which would be reradiated into space in the 10-micron band.
Offhand, I should think rotational and gravitational stresses alone would rule out such a structure of such dimensions. But since it is admittedly dangerous to assert that anything is impossible, I shall confine myself to the questions of economics. Even Dyson intimates that the project would take several thousand years to complete; he calculates the energy required as equal to the sun's total output for eight centuries, and one does have to eat meanwhile. And meanwhile, too, the population growth necessitating this project will presumably continue. As Hauser remarks in the same issue [Science, Vol. 131, 1960, page 1642], at our present-day rate of increase we would reach "a population of one person per square foot of the land surface of the earth in less than 800 years. Thus, the economic surplus needed for the biosphere project would be consumed long before the latter got well started.
If we assume a ratio of population increase to industrial expansion low enough so that this contretemps does not occur, we must ask ourselves how any intelligent species could be induced to patiently to continue this enormous task, millennium after millennium. True, our human history contains epochs of grandiose and useless construction, such as the pyramid building of Egypt, but they never lasted very long. Any revolutionist who promised relief from the crushing burden of the biosphere project would be well received! He could doubtless get support for some or other population-control program; those who demurred would be martyred by exasperated taxpayers, or the equivalent thereof.
Of course, the entire species might by advanced psychological techniques, be conditioned into such an antlike state that its government could never be overthrown, or break down from internal stresses, or evolve into something new. But given subjects as meek as this, and nor reason to breed vast armies (for only a well-established world government could seriously entertain these ideas in the first place), the masters could regulate birth and death by fiat. Thus, the population would have stabilized at some rational figure and projects such as Dyson's would never be indicated.
In short, uncontrolled population growth will make the construction of artificial biospheres impossible, and control will make them unnecessary. So astronomical discovery of infrared sources won't prove anything about the inhabitants of other planets.
Paul Anderson
3 Las Palomas Road
Orinda, California
The suggestion by Freeman J. Dyson for investigating solar far-infrared radiation as one way to detect extraterrestrial intelligence sounds quite practical and sensible.
This leads me to suspect that if Dyson's assumption is correct - that intelligent beings exist of a far higher order technological achievement than our own - it would be well - nigh impossible for such beings not to have detected us.
Eugene A. Sloane
Air Engineering
Detroit, Michigan
RESPONSE: In reply to Maddox, Anderson and Sloane, I would only like to add the following points, which were omitted from my earlier communication.
1. A solid shell or ring surrounding a star is mechanically impossible. The form of "biosphere" which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star. The size and shape of the individual objects would be chosen to suit the inhabitants. I did not indulge in speculations concerning the constructional details of the biosphere, since the expected emission of infrared radiation is independent of such details.
2. It is a question of taste whether one believes that a stabilization of population and industry is more likely to occur close to the Malthusian limit or far below that limit. My personal belief is that only a rigid "police state" would likely to stabilize itself far below the Malthusian limit. I consider that an open society would be likely to expand by proliferation of the "city-states" each pursuing an independent orbit in space. Such an expansion need not be planned or dictatorially imposed; unless it were forcibly stopped it would result in the gradual emergence of an artificial biosphere of the kind I have suggested. This argument is admittedly anthropomorphic, and I resent it in full knowledge that the concepts of "police state" and "open society" are probably meaningless outside our own species.
3. The discovery of an intense point source of infrared radiation would not by itself imply that extraterrestrial intelligence has been found. On the contrary, one of the strongest reasons for conducting a search for such sources is that many new types of natural astronomical objects might be discovered.
Freeman J. Dyson
Institute for Advanced Study
Princeton, New Jersey
Dyson's article was inspired by Olaf Stapledon's Star Maker and by J. D. Bernal.
In bed with Templeton »
No Dyson Spheres Found Yet
by Sean
dyson sphere In 1960, Freeman Dyson proposed an audacious form that future technology might take: the Dyson Sphere. It’s a simple idea, once you stop thinking in terms of “I wonder how that could be done?” and start thinking along the lines of “I wonder what is physically possible?” Dyson reasoned that an efficient civilization wouldn’t want all of the valuable energy from its home star to fly uselessly into outer space, so they would try to capture it. The solution is then obvious: a sphere of matter that encircles the entire star. It’s worth quoting a bit from Dyson’s original paper:
The material factors which ultimately limit the expansion of a technically advanced species are the supply of matter and the supply of energy. At present the material resources being exploited by the human species are roughly limited to the biosphere of the earth, a mass of the order of 5 x 1019 grams. Our present energy supply may be generously estimated at 1020 ergs per second. The quantities of matter and energy which might conceivably become accessible to us within the solar system are 2 x 1030 grams (the mass of Jupiter) and 4 x 1033 ergs per second (the total energy output of the sun).
The reader may well ask in what sense can anyone speak of the mass of Jupiter or the total radiation from the sun as being accessible to exploitation. The following argument is intended to show that an exploitation of this magnitude is not absurd. First of all, the time required for an expansion of population and industry by a factor of 1012 is quite short, say 3000 years if an average growth rate of 1 percent per year is maintained. Second, the energy required to disassemble and rearrange a planet the size of Jupiter is about 1044 ergs, equal to the energy radiated by the sun in 800 years. Third, the mass of Jupiter, if distributed in a spherical shell revolving around the sun at twice the Earth’s distance from it, would have a thickness such that the mass is 200 grams per square centimeter of surface area (2 to 3 meters, depending on the density). A shell of this thickness could be made comfortably habitable, and could contain all the machinery required for exploiting the solar radiation falling onto it from the inside.
Old news, right. What I hadn’t realized is that there is something called the Fermilab Dyson Sphere search program, led by Richard Carrigan, which recently updated its results (summarized in the title of this post). A star like the Sun radiates something pretty close to a blackbody spectrum; but if you capture all of the energy in the Sun’s radiation, and then re-radiate it from a much larger sphere (e.g. one astronomical unit in radius), it comes out at a much lower temperature — a few hundred Kelvin. Dyson therefore proposed a search strategy, looking for blackbody objects radiating in the far infrared, around 10 microns in wavelength.
And the search is now going on! Indeed, Carrigan’s most recent results were just released on astro-ph a few weeks ago:
IRAS-based whole-sky upper limit on Dyson Spheres
Authors: Richard A. Carrigan Jr
Abstract: A Dyson Sphere is a hypothetical construct of a star purposely cloaked by a thick swarm of broken-up planetary material to better utilize all of the stellar energy. A clean Dyson Sphere identification would give a significant signature for intelligence at work. A search for Dyson Spheres has been carried out using the 250,000 source database of the IRAS infrared satellite which covered 96% of the sky. The search has used the Calgary data collection of the IRAS Low Resolution Spectrometer (LRS) to look for fits to blackbody spectra. Searches have been conducted for both pure (fully cloaked) and partial Dyson Spheres in the blackbody temperature region 100 < T < 600 deg K. Other stellar signatures that resemble a Dyson Sphere are reviewed. When these signatures are used to eliminate sources that mimic Dyson Spheres very few candidates remain and even these are ambiguous. Upper limits are presented for both pure and partial Dyson Spheres. The sensitivity of the LRS was enough to find solar-sized Dyson Spheres out to 300 pc, a reach that encompasses a million solar- type stars.
It’s too bad the search has thus far not turned up too many promising candidates. The Fermi Paradox continues to be paradoxical.
One famous account of the first contact between an extraterrestrial civilization and the human race was told in the classic 1951 Robert Wise film, The Day the Earth Stood Still. It’s now been remade by director Scott Derrickson, starring Keanu Reeves as the alien Klaatu,who an asshole from the Peta Planet of hippie jerkoffs. In the emerging spirit of science and entertainment exchanges, there will be a panel discussion at Caltech’s Beckman Auditorium this Friday (the 5th) with Derrickson and Reeves holding up the Hollywood side of things, and roboticist Joel Burdick and I holding up the science end. Don’t quote me on this, but I think it’s at 6:00, and the movie will be screened before the panel. Should be fun.
Shells Around Suns May Have Been Built
Science News Letter, June 18, 1960, page 389, Astronomy
Intelligent beings in another solar system could have hidden their sun by knocking their planets apart and using the pieces to build a hollow ball around their sun.
Dr. Freeman J. Dyson of the Institute for Advanced Study, Princeton, N. J., says that other civilizations may be millions of years ahead of the earth. They may have rearranged their solar systems to meet the needs of their exploding populations.
A hollow ball built around the sun would solve the space and energy problems. It would also cut off the sun's light. To detect such an advanced civilization, earthlings would have to detect the invisible heat radiation from the hollow ball.
A search for such infrared radiation should be coordinated with, Project Ozma, a program now underway for detecting artificial radio waves from nearby stars, Dr. Dyson reports in Science, Vol. 131, 1960, page 1667.
Using our own solar system as an example, Dr. Dyson calculates that it would take about 3,000 years for population and technology to expand one trillion times at the rate of one percent a year. Pressures of population and energy needs could be met only by trapping all of the sun’s radiated energy.
To trap the energy, earthlings could knock apart the planet Jupiter and rearrange it as a hollow ball about 10 feet thick with a diameter twice the size of earth's orbit. This would take all the energy given off by the sun in 800 years. Such a sphere would be “comfortably habitable.”
Dr. Dyson states he is not suggesting that this is what will happen in the solar system, but only proposes what may have happened in other stellar systems.
Search for Artificial Stellar Sources of Infrared Radiation
Freeman John Dyson, Science, Vol. 131, June 3, 1960, pp. 1667-1668.
ABSTRACT: If extraterrestrial intelligent beings exist and have reached a high level of technical development, one by-product of their energy metabolism is likely to be the large-scale conversion of starlight into far-infrared radiation. It is proposed that a search for sources of infrared radiation should accompany the recently initiated search for interstellar radio communications.
Cocconi and Morrison [1] have called attention to the importance and feasibility of listening for radio signals transmitted by extraterrestrial intelligent beings. They propose that listening aerials be directed toward nearby stars which might be accompanied by planets carrying such beings. Their proposal is now being implemented [2].
The purpose of this report is to point out other possibilities which ought to be considered in planning any serious search for evidence of extraterrestrial beings. We start from the notion that the time scale for industrial and technical development of these beings is likely to be very short in comparison with the time scale of stellar evolution. It is therefore overwhelmingly probable that any such beings observed by us will have been in existence for millions of years, and will have already reached a technological level surpassing ours by many orders of magnitude. It is then a reasonable working hypothesis that their habitat will have been expanded to the limits set by Malthusian principles.
We have no direct knowledge of the material conditions which these beings would encounter in their search for lebensraum. We therefore consider what would be the likely course of events if these beings had originated in a solar system identical with ours. Taking our own solar system as the model, we shall reach at least a possible picture of what may be expected to happen elsewhere. I do not argue that this is what will happen in our system; I only say that this is what may have happened in other systems.
The material factors which ultimately limit the expansion of a technically advanced species are the supply of matter and the supply of energy. At present the material resources being exploited by the human species are roughly limited to the biosphere of the earth, a mass of the order of 5 x 1019 grams. Our present energy supply may be generously estimated at 1020 ergs per second. The quantities of matter and energy which might conceivably become accessible to us within the solar system are 2 x 1030 grams (the mass of Jupiter) and 4 x 1033 ergs per second (the total energy output of the sun).
The reader may well ask in what sense can anyone speak of the mass of Jupiter or the total radiation from the sun as being accessible to exploitation. The following argument is intended to show that an exploitation of this magnitude is not absurd. First of all, the time required for an expansion of population and industry by a factor of 1012 is quite short, say 3000 years if an average growth rate of 1 percent per year is maintained. Second, the energy required to disassemble and rearrange a planet the size of Jupiter is about 1044 ergs, equal to the energy radiated by the sun in 800 years. Third, the mass of Jupiter, if distributed in a spherical shell revolving around the sun at twice the Earth's distance from it, would have a thickness such that the mass is 200 grams per square centimeter of surface area (2 to 3 meters, depending on the density). A shell of this thickness could be made comfortably habitable, and could contain all the machinery required for exploiting the solar radiation falling onto it from the inside.
It is remarkable that the time scale of industrial expansion, the mass of Jupiter, the energy output of the sun, and the thickness of a habitable biosphere all have consistent orders of magnitude. It seems, then a reasonable expectation that, barring accidents, Malthusian pressures will ultimately drive an intelligent species to adopt some such efficient exploitation of its available resources. One should expect that, within a few thousand years of its entering the stage of industrial development, any intelligent species should be found occupying an artificial biosphere which completely surrounds its parent star.
If the foregoing argument is accepted, then the search for extraterrestrial intelligent beings should not be confined to the neighborhood of visible stars. The most likely habitat for such beings would be a dark object, having a size comparable with the Earth's orbit, and a surface temperature of 200 deg. to 300 deg. K. Such a dark object would be radiating as copiously as the star which is hidden inside it, but the radiation would be in the far infrared, around 10 microns wavelength.
It happens that the earth's atmosphere is transparent to radiation within the wavelength in the range from 8 to 12 microns. It is therefore feasible to search for "infrared stars" in this range of wavelengths, using existing telescopes on the earth's surface. Radiation in this range from Mars and Venus has not only been detected but has been spectroscopically analyzed in some detail [3].
I propose then that a search for point sources of infrared radiation be attempted, either independently or in conjunction with the search for artificial radio emissions. A scan of the entire sky for objects down to the 5th or 6th magnitude would be desirable, but is probably beyond the capability of existing techniques of detection. If an undirected scan is impossible, it would be worthwhile as a preliminary measure to look for anomalously intense radiation in the 10-micron range associated with visible stars. Such radiation might be seen in the neighborhood of a visible star under either of two conditions. A race of intelligent beings might be unable to exploit fully the energy radiated by their star because an insufficiency of accessible matter, or they might live in an artificial biosphere surrounding one star of a multiple system in which one or more component stars are unsuitable for exploitation and would still be visible to us. It is impossible to guess the probability that either of these circumstances would arise for a particular race of extraterrestrial intelligent beings. But it is reasonable to begin the search for infrared radiation of artificial origin by looking in the direction of nearby visible stars, and especially in the direction of stars which are known to be binaries with visible companions.
References
1. G. Cocconi and P. Morrison, Nature, Vol. 184, 1959, pp. 844-846.
2. Science, Vol. 131, April 29, 1960, page 1303.
3. Astrophysics Journal, Vol. 31, 1960, pp. 459, 470.
Science Vol. 132, July 22, 1960, pp. 250-253.
Letters and Response
Search for Artificial Stellar Sources of Infrared Radiation
It is unfortunate that Dyson's suggestion [Vol. 131, 1960, page 1667] as to how intelligent beings might survive after reaching "the limits set by Malthusian principles" does not do justice to the intelligence of these beings by explaining how they would overcome some of the obstacles which, at first sight, would seem to militate against their curious way of life.
Dyson's report describes a uniformly thick shell of fluid with a thickness of a meter or two and a radius twice the earth's distance from the sun. The shell is said to revolve around the central star, which implies that the material revolves as a whole. Presumably the material of the shell must be enclosed on both surfaces by transparent plastic sheaths of similar constructions, for self-gravitation cannot be expected to make the material cohere. However it is not conceivable that it would be possible to quarry from the material of a planet like Jupiter sufficient structural steel to keep the shell rigid against the shear forces and those that would tend to move material towards the equatorial plane.
Therefore it must be assumed that radiation pressure must play a part in supporting the shell, so that its form will be that of an oblate spheroid rather than a sphere. For example, material at the poles of revolution of the shell would be supported entirely by radiation pressure, so that the polar radius of the shell would necessarily be less than the equatorial radius. However, a cursory calculation will show that this would be possible only at a distance from the central star comparable to but less than the radius of the sun.
Beings of lesser intelligence, not having discovered the appropriate laws of physics, might therefore seek some other distribution of their dismantled Jupiter that would have more intrinsic stability - for example, a torus lying in a plane perpendicular to the axis of its own rotation. The mass of Jupiter distributed in this way would yield a torus whose cross-sectional area was comparable with that of the moon, but unfortunately the flux of stellar radiation would be reduced by a factor of 109.
With conventional laws of physics, however, as Laplace was the first to show, even this arrangement would not be stable, and it is to be expected that the material of the torus would coalesce into one or more planetary objects. This suggests that the present state of intelligence, the dispersal of Jupiter into a thin shell about the sun would not be an effective means of escaping the consequences of continued population growth but that it might be an experiment with important bearing on various theories of origin of the solar system. It would, for example, be interesting to see whether the outcome of the experiment was the recreation of Jupiter or the creation of a number of asteroids.
Another point is that a search for infrared stars would be valuable even in conventional science for the light it might throw on the evolution of stars which are very young or very small as compared with the sun.
John Maddox
Washington Post
Washington, D.C.
Freeman Dyson's report suggesting that intelligent life elsewhere in the universe may be detected by looking for sources of infrared radiation was delightful. However, as an old science-fiction hand, I feel obliged to sound a cautionary note to the scientists. Or am I merely to dense to recognize a satire?
The basis of Dyson's argument is that an industrial culture may eventually occupy an artificial biosphere completely surrounding its sun, thus maximizing the territory and energy available for population expansion "to the limits set by Malthusian principles. The mass of Jupiter could be converted into a "spherical shell revolving around the sun at twice the Earth's distance from it," utilizing incident solar radiation which would be reradiated into space in the 10-micron band.
Offhand, I should think rotational and gravitational stresses alone would rule out such a structure of such dimensions. But since it is admittedly dangerous to assert that anything is impossible, I shall confine myself to the questions of economics. Even Dyson intimates that the project would take several thousand years to complete; he calculates the energy required as equal to the sun's total output for eight centuries, and one does have to eat meanwhile. And meanwhile, too, the population growth necessitating this project will presumably continue. As Hauser remarks in the same issue [Science, Vol. 131, 1960, page 1642], at our present-day rate of increase we would reach "a population of one person per square foot of the land surface of the earth in less than 800 years. Thus, the economic surplus needed for the biosphere project would be consumed long before the latter got well started.
If we assume a ratio of population increase to industrial expansion low enough so that this contretemps does not occur, we must ask ourselves how any intelligent species could be induced to patiently to continue this enormous task, millennium after millennium. True, our human history contains epochs of grandiose and useless construction, such as the pyramid building of Egypt, but they never lasted very long. Any revolutionist who promised relief from the crushing burden of the biosphere project would be well received! He could doubtless get support for some or other population-control program; those who demurred would be martyred by exasperated taxpayers, or the equivalent thereof.
Of course, the entire species might by advanced psychological techniques, be conditioned into such an antlike state that its government could never be overthrown, or break down from internal stresses, or evolve into something new. But given subjects as meek as this, and nor reason to breed vast armies (for only a well-established world government could seriously entertain these ideas in the first place), the masters could regulate birth and death by fiat. Thus, the population would have stabilized at some rational figure and projects such as Dyson's would never be indicated.
In short, uncontrolled population growth will make the construction of artificial biospheres impossible, and control will make them unnecessary. So astronomical discovery of infrared sources won't prove anything about the inhabitants of other planets.
Paul Anderson
3 Las Palomas Road
Orinda, California
The suggestion by Freeman J. Dyson for investigating solar far-infrared radiation as one way to detect extraterrestrial intelligence sounds quite practical and sensible.
This leads me to suspect that if Dyson's assumption is correct - that intelligent beings exist of a far higher order technological achievement than our own - it would be well - nigh impossible for such beings not to have detected us.
Eugene A. Sloane
Air Engineering
Detroit, Michigan
RESPONSE: In reply to Maddox, Anderson and Sloane, I would only like to add the following points, which were omitted from my earlier communication.
1. A solid shell or ring surrounding a star is mechanically impossible. The form of "biosphere" which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star. The size and shape of the individual objects would be chosen to suit the inhabitants. I did not indulge in speculations concerning the constructional details of the biosphere, since the expected emission of infrared radiation is independent of such details.
2. It is a question of taste whether one believes that a stabilization of population and industry is more likely to occur close to the Malthusian limit or far below that limit. My personal belief is that only a rigid "police state" would likely to stabilize itself far below the Malthusian limit. I consider that an open society would be likely to expand by proliferation of the "city-states" each pursuing an independent orbit in space. Such an expansion need not be planned or dictatorially imposed; unless it were forcibly stopped it would result in the gradual emergence of an artificial biosphere of the kind I have suggested. This argument is admittedly anthropomorphic, and I resent it in full knowledge that the concepts of "police state" and "open society" are probably meaningless outside our own species.
3. The discovery of an intense point source of infrared radiation would not by itself imply that extraterrestrial intelligence has been found. On the contrary, one of the strongest reasons for conducting a search for such sources is that many new types of natural astronomical objects might be discovered.
Freeman J. Dyson
Institute for Advanced Study
Princeton, New Jersey
Dyson's article was inspired by Olaf Stapledon's Star Maker and by J. D. Bernal.
Sci Fi Science!
Great Show!
14 September 2010 | by sedativchunk (United States) – See all my reviews
I love Sci Fi Science! I am a big space and science enthusiast as well as a fan of science fiction. Unfortunately in todays world there is a brick wall that separates the factions of both those things. Sci Fi Science: Physics of the Impossible is one show that thins the line between science fiction and real science, and that is a great thing.
When I first watched this show a few weeks ago, I was very skeptical. It seemed silly and unrealistic. Lasers on the Moon? Asteroids crashing into Mars to terraform the planet? As ridiculous as Michio Kaku's ideas sound at first, they are, in my opinion, very realistic as well as practical. Kaku is attempting to explain things scientifically that many other ignorant so called scientist seem to put off as being impossible. Isn't science supposed to be about making the impossible a reality? The main thing that turned me off of this show at first was the overall quality and narration. After recently watching Stephen Hawking's brilliant "Into the Universe" series, this show seemed to be lacking. It wasn't quite at the level Hawking's three part series was. But Stephen Hawking spent over two years editing and narrating three episodes of his show, so of course they are going to be of high quality. Kaku's show is more simplified and is geared towards being a weekly television show rather than a huge one time only deal show, so I lowered the bar for this show and embraced it for what it is. In the end, I found I actually enjoyed it!
Kaku's show seems to be more geared towards sci fi fans more than actual scientist, but that does not mean it is not worth checking out if you are a scientist or science enthusiast. How would you go about creating a society on Mars? What is the best way to protect Earth's ecosystem permanently from killer asteroids? Colonizing Mars and protecting Earth from killer asteroids are more than science fiction. They both could happen one day hundreds of years from now. I think it is nice to see a real scientist actually talk about real problems of the future and come up with a practical solution on how to solve them. For the skeptics, I will talk about one of Kaku's episodes and challenge it's ideas. Being a curious person and computer scientist myself, I challenged Kaku's theory on terraforming Mars. Kaku did an episode of Sci Fi Science where he talked about how we would be able to attach rockets to asteroids from the asteroid belt between Mars and Jupiter, slingshot them around Jupiter and send them hurling towards Mars. When the asteroids would impact, they would theoretically melt the polar ice caps on Mars and create a greenhouse effect on Mars to heat the entire planet. This would hypothetically make the planet suitable for life as well as protect it from the Sun's deadly radiation.
As much as I tried to challenge this asteroid concept, in the end, I couldn't find a better solution. There are variables involved. How would we attach rockets to massive asteroids? How would we navigating them back through the asteroid belt after sling shotting around Jupiter? How long would the process take? How long would Mars be hot for or how long would the effects last? As many questions as there are, the idea is practical and realistic. How else do you heat an entire planet? Mirrors reflecting light from the sun on the planet? Changing the albedo of the entire surface of the planet? The cost and ideas of those other theories are astronomical. Building guided missiles and sling shotting objects in space has been done before, so why can't that be applied to asteroids and Mars?
Have fun and watch this show, challenge Kaku's ideas and you will find that his show is not all just silly business for science fiction. It is real, practical science. Give this show a try. It may not be everyones flavor of science, but I like it more than the typical Discovery Channel type show.
The big flaw? Parallel circles that don't orbit the sun won't work. The concept illustrated in A New Solar System will collapse into chaos. For a sphere to work, the individual elements will have to orbit in great circles around the periphery of the sphere also creating chaotic conditions as orbits must cross each other and perturbations become extremely complex. The only truly stable formation would be the Dyson ring with all elements in the same orbital plane. A good illustration of why the sphere wouldn't work are the rings of Saturn. There are none in skewed orbits and that also shows the fate of the sphere. Gravity will collapse it into a ring over time if it is attempted.
http://en.wikipedia.org/wiki/Dyson_sphere#Dyson_swarm
Just the ring, Michio! It's an ambitious enough project in itself.
P.S. (Sept 18) With elements of a ring or sphere in orbit, artificial gravity can't be created on the inside as Kaku proposed. To maintain orbit gravitational and centripetal forces must balance resulting in 0g forces. Any attempt to accelerate the ring/sphere to produce 1g will quickly blow it apart.
10 months ago
Presumably a Dyson Sphere would only be constructed around a dwarf-type star as they are extremely long-lived and more stable than larger stars. But even those stars would not last forever. And the death of such a star would probably be a nonviolent cooling. What bothers me about the DS is the amount of matter required to build it. All system bodies would have to be liquidated and much more would be required. I don't see how any race of beings, regardless of advancement, could do it.
Well,unless they are a super civilization like Atlanteans and Sidairians.Check out Terra-Prime at Maveric Universe Wiki
14 September 2010 | by sedativchunk (United States) – See all my reviews
I love Sci Fi Science! I am a big space and science enthusiast as well as a fan of science fiction. Unfortunately in todays world there is a brick wall that separates the factions of both those things. Sci Fi Science: Physics of the Impossible is one show that thins the line between science fiction and real science, and that is a great thing.
When I first watched this show a few weeks ago, I was very skeptical. It seemed silly and unrealistic. Lasers on the Moon? Asteroids crashing into Mars to terraform the planet? As ridiculous as Michio Kaku's ideas sound at first, they are, in my opinion, very realistic as well as practical. Kaku is attempting to explain things scientifically that many other ignorant so called scientist seem to put off as being impossible. Isn't science supposed to be about making the impossible a reality? The main thing that turned me off of this show at first was the overall quality and narration. After recently watching Stephen Hawking's brilliant "Into the Universe" series, this show seemed to be lacking. It wasn't quite at the level Hawking's three part series was. But Stephen Hawking spent over two years editing and narrating three episodes of his show, so of course they are going to be of high quality. Kaku's show is more simplified and is geared towards being a weekly television show rather than a huge one time only deal show, so I lowered the bar for this show and embraced it for what it is. In the end, I found I actually enjoyed it!
Kaku's show seems to be more geared towards sci fi fans more than actual scientist, but that does not mean it is not worth checking out if you are a scientist or science enthusiast. How would you go about creating a society on Mars? What is the best way to protect Earth's ecosystem permanently from killer asteroids? Colonizing Mars and protecting Earth from killer asteroids are more than science fiction. They both could happen one day hundreds of years from now. I think it is nice to see a real scientist actually talk about real problems of the future and come up with a practical solution on how to solve them. For the skeptics, I will talk about one of Kaku's episodes and challenge it's ideas. Being a curious person and computer scientist myself, I challenged Kaku's theory on terraforming Mars. Kaku did an episode of Sci Fi Science where he talked about how we would be able to attach rockets to asteroids from the asteroid belt between Mars and Jupiter, slingshot them around Jupiter and send them hurling towards Mars. When the asteroids would impact, they would theoretically melt the polar ice caps on Mars and create a greenhouse effect on Mars to heat the entire planet. This would hypothetically make the planet suitable for life as well as protect it from the Sun's deadly radiation.
As much as I tried to challenge this asteroid concept, in the end, I couldn't find a better solution. There are variables involved. How would we attach rockets to massive asteroids? How would we navigating them back through the asteroid belt after sling shotting around Jupiter? How long would the process take? How long would Mars be hot for or how long would the effects last? As many questions as there are, the idea is practical and realistic. How else do you heat an entire planet? Mirrors reflecting light from the sun on the planet? Changing the albedo of the entire surface of the planet? The cost and ideas of those other theories are astronomical. Building guided missiles and sling shotting objects in space has been done before, so why can't that be applied to asteroids and Mars?
Have fun and watch this show, challenge Kaku's ideas and you will find that his show is not all just silly business for science fiction. It is real, practical science. Give this show a try. It may not be everyones flavor of science, but I like it more than the typical Discovery Channel type show.
The big flaw? Parallel circles that don't orbit the sun won't work. The concept illustrated in A New Solar System will collapse into chaos. For a sphere to work, the individual elements will have to orbit in great circles around the periphery of the sphere also creating chaotic conditions as orbits must cross each other and perturbations become extremely complex. The only truly stable formation would be the Dyson ring with all elements in the same orbital plane. A good illustration of why the sphere wouldn't work are the rings of Saturn. There are none in skewed orbits and that also shows the fate of the sphere. Gravity will collapse it into a ring over time if it is attempted.
http://en.wikipedia.org/wiki/Dyson_sphere#Dyson_swarm
Just the ring, Michio! It's an ambitious enough project in itself.
P.S. (Sept 18) With elements of a ring or sphere in orbit, artificial gravity can't be created on the inside as Kaku proposed. To maintain orbit gravitational and centripetal forces must balance resulting in 0g forces. Any attempt to accelerate the ring/sphere to produce 1g will quickly blow it apart.
10 months ago
Presumably a Dyson Sphere would only be constructed around a dwarf-type star as they are extremely long-lived and more stable than larger stars. But even those stars would not last forever. And the death of such a star would probably be a nonviolent cooling. What bothers me about the DS is the amount of matter required to build it. All system bodies would have to be liquidated and much more would be required. I don't see how any race of beings, regardless of advancement, could do it.
Well,unless they are a super civilization like Atlanteans and Sidairians.Check out Terra-Prime at Maveric Universe Wiki
Thursday, September 9, 2010
Giant-Size Spider-Man
Giant-Size Spider-Man.THE YESTERDAY CONNECTION
In 1934, Doc Savage and his men encounter a strange ,beautiful ,blue skinned woman from a parallel dimension, who seeks his help in vanquishing another strange, violent being, also from her dimension. Saku,the world she comes from was described as a world where our dimension of time corresponds to a linear dimension. Thus merely by traveling a linear distance on Saku, a traveler may emerge on Earth many years before or after an earlier visit.Where as this seems to make sense,the dimension time moves through space,than space moving through or is the other way around,dosen't much sense in the light many believe time and space are not separate,but something called space time.Anyway,the whole Saku would is silly,with little gyro pyramides floating about their seas Natives of Saku possess some forms of advanced equipment, capable of space-time manipulation, and the transubstantiator
THE YESTERDAY CONNECTION
A scientist and sub-space explorer, she developed some unknown grievance with Tarros and tried to destroy him. When she found out that he had merely been transformed, she traveled to find him on Earth in 1934, where she enlisted Doc Savage and his allies. They succeeded in trapping Tarros. In the modern era, when Tarros would have escaped, she tried to convince Spidey to destroy him. Spidey saw through her, freed Tarros, and let him take her back to Saku.A scientist and sub-space explorer, she developed some unknown grievance with Tarros and tried to destroy him. When she found out that he had merely been transformed, she traveled to find him on Earth in 1934, where she enlisted Doc Savage and his allies. They succeeded in trapping Tarros. In the modern era, when Tarros would have escaped, she tried to convince Spidey to destroy him. Spidey saw through her, freed Tarros, and let him take her back to Saku.
Desinna was working on a project exploring sub-space with her assistant Tarros. Tarros notified her of a breakthrough, a cosmic twisting of the space-time barrier. However, in his zeal to show it to her, he tripped and fell into their prototype space-time device, and a power surge slew his physical form, transforming him into an energy being and sending him to another dimension.
Desinna created her transubtantiator for (1) translation of her words into another language, (2) creation of a protective force field, (3) tracking energy signatures, and (4) penetrating the dimensions of time and space.Disinna used it to arrive on Earth at the same time as Tarros, and she observed his fully transformed form. Identifying it as evil and insane, she then traveled back a few hours in time to enlist the aid of others for assistant before Tarros would arrive.
- In 1934, Doc Savage received a message that informed him of an impending assassination attempt on mayor Fiorello La Guardia during the dedication of a construction site. Savage and his allies prevented the assassination, but he then correctly determined that the message was from another world, and that its true meaning indicated a threat at the same construction site, but occurring that evening. They returned to the site, where they were met by Desinna, who told him of the menace from beyond time, Tarros.
Just then, Tarros arrived, denouncing Desinna and grabbing her. Savage's ally, Monk, nailed Tarros in the back of the head with a brick, causing him to drop Desinna, and Doc Savage, Renny, and Ham lassoed his neck in an effort to bring him down. The giant Tarros easily broke free from them, leaving them strewn about the ground. Savage sent Renny and Long Tom on an errand, while he occupied Tarros with anything he could get his hands on. His allies completed their errand successfully, and sent him a special cadmium liquid. Savage used this liquid to damped Tarros' electrical energy, trapping him inside the foundation stone for the building that La Guardia had just dedicated.
Several decades later, in the modern era, that same building was slated for demolition. Desinna traveled to that time and used her transubstantiator to send a Morse Code signal that she needed Spider-Man's help. Spidey swung to the scene to investigate, and Desinna told him of the past of Tarros, and of her 1934 adventure. She was interrupted in mid-story when Tarros appeared attempted to capture Desinna once again. Spidey tried in vain to stop the powerful Tarros, until he found an electrically operated jackhammer, which he used to disrupt and disperse his electrical form.
Desinna then finished her story, telling Spider-Man he must finish off Tarros for good. However, Spidey had taken a course in comparative languages and based on what he could understand, combined with Tarros tone when talking to Desinna, he had grown suspicious of Desinna's story. He correctly figured that Tarros was, in fact, the victim. Spidey shattered the foundation stone, freeing Tarros once again. Tarros then transported Desinna back to Saku, to face the music for her crimes, and he thanked Spidey for his help.
Doc succeeds in sealing the creature into the cornerstone of a building under construction, but has a weird feeling that the case is somehow unfinished. In 1974, the building is about to be demolished. The other-dimensional woman seeks Spider-Man's assistance in preventing the creature's escape. Instead, Spidey senses something wrong and demolishes the cornerstone with a jackhammer, freeing the creature. It turns out that the woman had tricked Doc into unjustly imprisoning the creature, and Spidey was able to right an ancient wrong.
Of course, even the chance to learn more about Doc Savage can't blind me to all flaws and there is one quibble. I'm not sure about the fact that, unlike Doc Savage, Spidey sorts out the situation because, unlike Savage, he lives in a time when men know that women aren't always trustworthy. Really? Has he never read any of those hard-boiled detective novels that were so big in Savage's time?
I'm not sure about the fact that, unlike Doc Savage, Spidey sorts out the situation because, unlike Savage, he lives in a time when men know that women aren't always trustworthy. Really? Has he never read any of those hard-boiled detective novels that were so big in Savage's time?Often guys like Sam Spade and Phillip Marlow meet dames who are untrustworthy.The whole Spider-Man and Doc Savage crossover really dosen't work,as does much of the story.The only really neat is Disinna and Saku transubtantiator.It looks allot like the later on Goa'uld Hand Device.
In 1934, Doc Savage and his men encounter a strange ,beautiful ,blue skinned woman from a parallel dimension, who seeks his help in vanquishing another strange, violent being, also from her dimension. Saku,the world she comes from was described as a world where our dimension of time corresponds to a linear dimension. Thus merely by traveling a linear distance on Saku, a traveler may emerge on Earth many years before or after an earlier visit.Where as this seems to make sense,the dimension time moves through space,than space moving through or is the other way around,dosen't much sense in the light many believe time and space are not separate,but something called space time.Anyway,the whole Saku would is silly,with little gyro pyramides floating about their seas Natives of Saku possess some forms of advanced equipment, capable of space-time manipulation, and the transubstantiator
THE YESTERDAY CONNECTION
A scientist and sub-space explorer, she developed some unknown grievance with Tarros and tried to destroy him. When she found out that he had merely been transformed, she traveled to find him on Earth in 1934, where she enlisted Doc Savage and his allies. They succeeded in trapping Tarros. In the modern era, when Tarros would have escaped, she tried to convince Spidey to destroy him. Spidey saw through her, freed Tarros, and let him take her back to Saku.A scientist and sub-space explorer, she developed some unknown grievance with Tarros and tried to destroy him. When she found out that he had merely been transformed, she traveled to find him on Earth in 1934, where she enlisted Doc Savage and his allies. They succeeded in trapping Tarros. In the modern era, when Tarros would have escaped, she tried to convince Spidey to destroy him. Spidey saw through her, freed Tarros, and let him take her back to Saku.
Desinna was working on a project exploring sub-space with her assistant Tarros. Tarros notified her of a breakthrough, a cosmic twisting of the space-time barrier. However, in his zeal to show it to her, he tripped and fell into their prototype space-time device, and a power surge slew his physical form, transforming him into an energy being and sending him to another dimension.
Desinna created her transubtantiator for (1) translation of her words into another language, (2) creation of a protective force field, (3) tracking energy signatures, and (4) penetrating the dimensions of time and space.Disinna used it to arrive on Earth at the same time as Tarros, and she observed his fully transformed form. Identifying it as evil and insane, she then traveled back a few hours in time to enlist the aid of others for assistant before Tarros would arrive.
- In 1934, Doc Savage received a message that informed him of an impending assassination attempt on mayor Fiorello La Guardia during the dedication of a construction site. Savage and his allies prevented the assassination, but he then correctly determined that the message was from another world, and that its true meaning indicated a threat at the same construction site, but occurring that evening. They returned to the site, where they were met by Desinna, who told him of the menace from beyond time, Tarros.
Just then, Tarros arrived, denouncing Desinna and grabbing her. Savage's ally, Monk, nailed Tarros in the back of the head with a brick, causing him to drop Desinna, and Doc Savage, Renny, and Ham lassoed his neck in an effort to bring him down. The giant Tarros easily broke free from them, leaving them strewn about the ground. Savage sent Renny and Long Tom on an errand, while he occupied Tarros with anything he could get his hands on. His allies completed their errand successfully, and sent him a special cadmium liquid. Savage used this liquid to damped Tarros' electrical energy, trapping him inside the foundation stone for the building that La Guardia had just dedicated.
Several decades later, in the modern era, that same building was slated for demolition. Desinna traveled to that time and used her transubstantiator to send a Morse Code signal that she needed Spider-Man's help. Spidey swung to the scene to investigate, and Desinna told him of the past of Tarros, and of her 1934 adventure. She was interrupted in mid-story when Tarros appeared attempted to capture Desinna once again. Spidey tried in vain to stop the powerful Tarros, until he found an electrically operated jackhammer, which he used to disrupt and disperse his electrical form.
Desinna then finished her story, telling Spider-Man he must finish off Tarros for good. However, Spidey had taken a course in comparative languages and based on what he could understand, combined with Tarros tone when talking to Desinna, he had grown suspicious of Desinna's story. He correctly figured that Tarros was, in fact, the victim. Spidey shattered the foundation stone, freeing Tarros once again. Tarros then transported Desinna back to Saku, to face the music for her crimes, and he thanked Spidey for his help.
Doc succeeds in sealing the creature into the cornerstone of a building under construction, but has a weird feeling that the case is somehow unfinished. In 1974, the building is about to be demolished. The other-dimensional woman seeks Spider-Man's assistance in preventing the creature's escape. Instead, Spidey senses something wrong and demolishes the cornerstone with a jackhammer, freeing the creature. It turns out that the woman had tricked Doc into unjustly imprisoning the creature, and Spidey was able to right an ancient wrong.
Of course, even the chance to learn more about Doc Savage can't blind me to all flaws and there is one quibble. I'm not sure about the fact that, unlike Doc Savage, Spidey sorts out the situation because, unlike Savage, he lives in a time when men know that women aren't always trustworthy. Really? Has he never read any of those hard-boiled detective novels that were so big in Savage's time?
I'm not sure about the fact that, unlike Doc Savage, Spidey sorts out the situation because, unlike Savage, he lives in a time when men know that women aren't always trustworthy. Really? Has he never read any of those hard-boiled detective novels that were so big in Savage's time?Often guys like Sam Spade and Phillip Marlow meet dames who are untrustworthy.The whole Spider-Man and Doc Savage crossover really dosen't work,as does much of the story.The only really neat is Disinna and Saku transubtantiator.It looks allot like the later on Goa'uld Hand Device.
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