Dyson Sphere Hunt Using Kepler Data

by Paul Gilster on October 11, 2012

The idea of the multiverse — an infinite number of universes co-existing with our own — has a philosophical and mathematical appeal, at least if you’re a follower of string theory. Indeed, there are those who would argue there could be as many as 10500 universes, each with its own particular characteristics, most probably inimical to the development of life. But I have to say that I’m far more interested in the universe that is demonstrably here, our own, and thus the news that Geoff Marcy has received a grant to look for Dyson spheres catches my eye more than news of a similar grant to physicist Raphael Bousso to probe multiverse theory.

Not that I have anything against Dr. Bousso (UC-Berkeley) and his work, and if he eventually does find a way to make predictions of multiverse theory that can be tested, I’m all for it. But I think the new grants, given to the researchers in a series called New Frontiers in Astronomy & Cosmology International Grants (funded through the UK’s Templeton Foundation), were wisely balanced between the practical (observational astronomy) and the highly theoretical. Marcy will use his to probe the continually swelling Kepler datastream looking for distinctive signatures.

Instead of planets, though, Marcy has more unusual targets, the vast structures Freeman Dyson hypothesized over fifty years ago that could ring or completely enclose their parent star. Such structures, the work of a Kardashev Type II civilization — one capable of drawing on the entire energy output of its star — would power the most power-hungry society and offer up reserves of energy that would support its continuing expansion into the cosmos, if it so chose. Marcy’s plan is to look at a thousand Kepler systems for telltale evidence of such structures by examining changes in light levels around the parent star.

Image: A Dyson sphere under construction. Credit: Steve Bowers.

Interestingly, the grant of $200,000 goes beyond the Dyson sphere search to look into possible laser traffic among extraterrestrial civilizations. Says Marcy:

“Technological civilizations may communicate with their space probes located throughout the galaxy by using laser beams, either in visible light or infrared light. Laser light is detectable from other civilizations because the power is concentrated into a narrow beam and the light is all at one specific color or frequency. The lasers outshine the host star at the color of the laser.”

The topic of Dyson spheres calls Richard Carrigan to mind. The retired Fermilab physicist has studied data from the Infrared Astronomical Satellite (IRAS) to identify objects that radiate waste heat in ways that imply a star completely enclosed by a Dyson sphere. This is unconventional SETI in that it presumes no beacons deliberately announcing themselves to the cosmos, but instead looks for signs of civilization that are the natural consequences of physics.

Carrigan has estimated that a star like the Sun, if enclosed with a shell at the radius of the Earth, would re-radiate its energies at approximately 300 Kelvin. Marcy will turn some of the thinking behind what Carrigan calls ‘cosmic archaeology’ toward stellar systems we now know to have planets, thanks to the work of Kepler. Ultimately, Carrigan’s ‘archaeology’ could extend to planetary atmospheres possibly marked by industrial activity, or perhaps forms of large-scale engineering other than Dyson spheres that may be acquired through astronomical surveys and remain waiting in our data to be discovered. All this reminds us once again how the model for SETI is changing.

For more, see two Richard Carrigan papers, the first being “IRAS-based Whole-Sky Upper Limit on Dyson Spheres,” Journal of Astrophysics 698 (2009), pp. 2075-2086 (preprint), and “Starry Messages: Searching for Signatures of Interstellar Archaeology,” JBIS 63 (2010), p. 90 (preprint). Also see James Annis, “Placing a limit on star-fed Kardashev type III civilisations,” JBIS 52, pp.33-36 (1999). A recent Centauri Dreams story on all this is Interstellar Archaeology on the Galactic Scale but see also Searching for Dyson Spheres and Toward an Interstellar Archaeology.

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Eniac October 17, 2012 at 20:49

The Dyson Sphere FAQ discusses rigid Dyson Shells, for which the level of technology is indeed ludicrously high.

I have accounted for the FAQ, and using its math I have explained how a standard shell lacks “only” one single order of magnitude in material strength, while an expanded one at 10 AU would require nothing stranger than diamond. If you call that ludicrous, then you are right. Personally, I would reserve the word ludicrous for femtotechnology, quarkonium matter and other things of that nature which are a few quantum leaps removed from diamond. If you had something else in mind that is ludicrous, please explain.

I am not trying to argue that this is something that should be, could be, or might be built. I am merely hoping someone might share my surprise and appreciation that this popular concept, which on first glance seems to require ludicrously implausible technology, actually doesn’t, on closer inspection.

A big, thin reflective balloon is not exactly that useful, at least for habitation.

The idea was that you thicken it gradually until it is a rigid, compressively supported shell, consistent with the standard Dyson Sphere concept. Sorry if that was not clear.

Whether it is useful for habitation is another matter. You could attach habitats to it, but why that would be better than free-floating ones is not clear. However, the defining purpose of a Dyson Sphere is to capture all the energy of a star, and that could indeed be achieved with such a structure. Why you would need to do that, is, again, not entirely clear. Personally, I think it is utterly useless to speculate about the motivations of anything or anybody who would be able to build such a thing.

Eniac October 17, 2012 at 21:07

James:

Even if an advanced race had the technological abilities to construct a Dyson Sphere, the sheer quantity of materials needed to do so is just absurd.

Absurd, perhaps. But, depending on size, material, and desired thickness, the required amounts would indeed be available in the solar system. See the FAQ for that. To get a nice and thick one, though, the Earth would have to be demolished. :-)

Brett Bellmore October 19, 2012 at 20:40

“Why you would need to do that, is, again, not entirely clear. ”

Takes an absurd amount of energy to launch large numbers of relativistic spacecraft. A Dyson sphere can provide absurd amounts of energy.

The only sort of Dyson sphere I think is really feasible, unless our understanding of physics is wrong, is the statite version. Fortunately, that only takes the material in a largish asteroid, and in return, you never lack for energy again. You can illuminate every planet in the solar system with the right amount of light, (And no UV, forget sunscreen!) to bring it into the habitable zone. You can launch interstellar colonization ships by the thousands. You can create so many huge space habitats a population a hundred times our would never feel crowded.

The task seems freakishly difficult from our perspective, but I expect that, by the end of the century, it will look, if not so much “easy”, entirely doable.

Eniac October 20, 2012 at 14:54

Brett Bellmore:

The only sort of Dyson sphere I think is really feasible, unless our understanding of physics is wrong, is the statite version

Why do you think this? See above for some arguments why this may not be the case, surprisingly.

Brett Bellmore October 21, 2012 at 13:50

1. Mass requirements quite modest.
a. Disassemble an asteroid, not several planets.
b. Construction can be completed in decades, not millennia.
c. Construction can be incremental. Is stable at all stages of construction.
2. Not subject to catastrophic failure if damaged.
a. Structure is not under compression, each individual tile supports itself.
b. Tiles can be replaced if destroyed by meteors, or “grown” in from edge.
3. No need for extraordinary materials. No “scrith” or even diamond.
4. Still accomplishes only practical goal of a Dyson sphere: Energy collection.

Yes, it’s interesting to know that, if you had access to several (hundred?) stellar systems worth of carbon, you might be able to build a diamond sphere around a star, which would catastrophically implode if damaged, and do nothing for you a more modest statite array wouldn’t do… I suppose a really wealthy interstellar society might do such a thing just to demonstrate that it had resources to waste. But probably not.

ljk October 22, 2012 at 14:04

Forget puny laser beams pushing sails from Dyson Shells: Someone is moving an entire galaxy around the Universe…

22 October 2012

Text, images, and video:

http://www.icrar.org/news/news_items/media-releases/astronomers-study-two-million-light-year-extragalactic-afterburner

ASTRONOMERS STUDY TWO MILLION LIGHT-YEAR ‘EXTRAGALACTIC AFTERBURNER’

Blasting over two million light-years from the center of a distant galaxy is a supersonic jet of material that looks strikingly similar to the afterburner flow of a fighter jet, except in this case the jet engine is a supermassive black hole and the jet material is moving at nearly the speed of light.

Research published over the weekend in the Astrophysical Journal Letters shows the galaxy-scale jet to have bright and dark regions, similar to the phenomenon in an afterburner exhaust called ‘shock diamonds.’

Eniac October 22, 2012 at 22:24

Brett:

Yes, it’s interesting to know that, if you had access to several (hundred?) stellar systems worth of carbon, you might be able to build a diamond sphere around a star, …

That is all I was trying to say. I see that we agree on this, otherwise, pretty much. I was hoping, though, it would be just one stellar system worth of carbon. If not, that would indeed reduce feasibility drastically.

I also agree that there are probably more worthy pursuits than this, although I am very reluctant to pass any kind of judgement on things so far removed from our experience.

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