October 15, 2015

Kepler Space telescope could have detected a dyson swarm or a very unlikely massive displacement of comets

For over four years, NASA’s Kepler mission measured the bright-ness of objects within a 100 square-degree patch of sky in the direction of the constellations Cygnus and Lyrae. The program’s targets were primarily selected to address the Kepler mission goals of discovering Earth-like planets orbiting other stars. Kepler targeted over 150,000 stars, primarily with a 30-minute observing cadence, leading to over 2.5-billion data points per year (over 10 billion data points over the nominal mission lifetime)

KIC 8462852 is an unique source in the Kepler field. They conducted numerous observations of the star and its environment, and our analysis characterizes the object as both remarkable (e.g., the “dipping” events in the Kepler light curve) and unremarkable (ground-based data reveal no deviation from a normal F-type star) at the same time. They presented an extensive set of scenarios to explain the occurrence of the dips, most of which are unsuccessful in explaining the observations in their entirety. However, of the various considered, they find that the break-up of a exocomet provides the most compelling explanation.

The light pattern suggests there is a lot of objects circling the star, in tight formation. That would be expected if the star were young. When our solar system first formed, four and a half billion years ago, a messy disk of dust and debris surrounded the sun, before gravity organized it into planets, and rings of rock and ice. But this unusual star isn’t young. If it were young, it would be surrounded by dust that would give off extra infrared light. There doesn’t seem to be an excess of infrared light around this star.

It appears to be mature.

If another star had passed through the unusual star’s system, it could have pulled a lot of comets inward. A huge number of comets could have made the dimming pattern. It would have had to have happened few thousand years ago. This would be a one in several million chance event for it to happen with the billions of year life of stars.

An interesting possibility is that we are looking at an alien built Dyson Swarm of orbiting solar arrays.

A "Dyson swarm" consists of a large number of independent constructs (usually solar power satellites and space habitats) orbiting in a dense formation around the star. This construction approach has advantages: components could be sized appropriately, and it can be constructed incrementally. Various forms of wireless energy transfer could be used to transfer energy between components and Earth. It is the most technically feasible method of gathering most of the power from a star.

Three astronomers want to point a radio dish at the star to look for wavelengths associated with technological civilisations. And the first observations could be ready to take place as early as January, with follow-up observations potentially coming even quicker.

Starting to build a Dyson Swarm is not that far beyond todays technology

Devon Crowe - Large Bubbles in Space

Large bubble structures in space could accelerate our ability to build large collectors for Dyson swarms.
Nasa Institute for Advanced Concepts in March 2007 meeting had Devon Crowe of PSI Corporation making large space structures from bubbles that are made rigid using metals or UV curing.

A single bubble can be 1 meter in earth gravity, 100 kilometer in low earth orbit or 1000 kilometers in deep space. Foams made of many bubbles could be far larger in size. The size of a 1000 kilometer bubble is nearly the size of Charon, the moon of Pluto. Charon is 1200 kilometers in diameter. Saturn's moon Tethys is 1050-1080 kilometers in diameter Ceres the largest object in the asteroid belt is 970 kilometers in diameter. A single tesselation foam (like in the picture) of 1000 kilometer bubbles would be about the size of Earth's moon. A Penrose tesselation like the one in the picture of 1000 kilometer bubbles would be in between the size of Neptune or Saturn. A Tesselation foam of 100 kilometer bubbles in earth orbit could form an object the size our existing moon or larger.

Kardavshev Two - Capturing 100% of the Solar Energy is 386 Yottawatts

1% of the solar energy is 3.86 Yottawatts or 3.86 X 10^24 watts

Using all of the deuterium in the Earth's Ocean would last a 1% of Kardashev Two civilization just over one year. Using all of the deuterium in the Gas giants (Jupiter, Saturn, Neptune and Uranus) would last a full Kardashev Two civilization 100,000 years.

10^12 W TW terawatt (The total power used by humans worldwide (about 16 TW in 2006) is commonly measured in this unit.)

10^15 W PW petawatt (the total energy flow of sunlight striking Earth's atmosphere is estimated at 174 PW)

Brett Bellmore Comment
Brett, a reader of this site, added a good comment and here it is. I would just mention that the shadowing problem could be mitigated with some level of energy efficient heliocentric orbit modification ability by the solar collectors. Also, up to a few percentage points of coverage (which is still trillions of times our current energy level) there is minimal shadowing problems.

The basic problem of the Dyson swarm is shadowing between the individual components. As you approach 100% coverage of the star, this becomes quite severe, meaning that you won't capture much of the star's energy, AND the individual units capturing the energy will be doing so in thermodynamically unfavorable circumstances, shadowed and exposed to the waste heat of other units.

The 'solid' sphere allows for 100% coverage, while providing better circumstances for thermodynamic efficiency, since both the absorbing and emitting surfaces are subject to steady state conditions, the spherical surface neither shadows itself on the inside, nor sees itself on the outside.

The classic problems of the 'solid' Dyson sphere are that, 1, it must be made of some absurdly strong material, 2, it is not self centering on the star, and 3, it is radically unstable while partially complete. All of these problems are a result of not analyzing the sphere as a real engineering proposal.

Problem 1 is solved by building the sphere as a dynamic structure: The absorbing and emitting surfaces would be stationary with respect to the star, but magnetically coupled to rotating bands of material traveling at well above orbital velocity. The greater this excess, the less of the structure has to be devoted to it, of course. This allows the structure to be self-supporting with all forces locally neutralized, it does not require materials stronger than we currently have access to. Elements not suited to structural purposes could be used as ballast in the support rings.

Problem 2 is almost trivially solved by the use of stabilizing algorithms, rather than reliance on natural stability. It does require some fraction of the weight and energy budget to be devoted to station keeping, but this could be very small, assuming the sphere were kept close to where it was supposed to be.

Problem 3; You don't build half a Dyson sphere. You build a band around the star, in a natural orbit. You then bring the bulk of it to a halt, while accelerating it's support ring to full speed. Build another such band, at an angle, repeat, attach to the first. The sphere can be assembled gradually as material is mined, and is stable at all stages in it's construction. The first ring requires no more material than would be found in a moderate sized asteroid.

Finally, you don't live on the Dyson sphere, this is inefficient. You beam the power to habitats distant from the enclosed star, where the background temperatures allow you to utilize the beamed energy with much higher efficiency. Dyson spheres are power sources for clouds of habitats in the cometary zone, not places where people will live.

A real-world Dyson sphere would not be some massive affair with people standing on it's inner surface, looking up at the sun. It would be a fairly thin structure devoted only to energy capture and transmission, probably amounting only to grams per square meter. It would be so light that a significant fraction of it's support might come from the star's radiation pressure. (Actually, the radiation pressure of the light reflecting about inside the sphere; The radiation pressure from the star's *net* emission would have to cancel out with that of the waste heat and transmitted power, or the sphere would continually rise in temperature.)

A statite deployed around our own sun would have to have an overall density of 0.78 grams per square meter of sail. The total mass of a bubble of such material 1 AU in radius would be about 2.17 × 10^20 kg, which is about the same mass as the asteroid Pallas. If you placed the statites closer to the sun at say 2.5 million miles from the surface of the sun, then the surface area would be about 28 trillion square miles or about 1000 times less than the 1 AU surface area. 2.17 × 10^17 kg (217 trillion tons) of material would be needed. The surface area would be about 12 times the surface area of the sun and about 150,000 times the 197 million square mile surface area of the Earth. About 100,000 tons of material (deployed as 2.5 million mile from the sun statite energy collectors) would be needed to capture the energy for a Kardashev level One civilization (equal to the solar energy hitting the earth). If you could get another one million miles closer then the amount of material would be halved. (2 million mile diameter sphere instead of 3 million mile). The systems would need to be able to handle the heat, variable magnetic fields and flares.

Let me repeat a key takeaway from this:
* when we have nanotechnology that is able to produce carbon solar sails/solar power collectors/statites that are about four times lighter than we can make now and produce and launch 100,000 tons of it and get it in close to the sun and transmit and use the power then we are at Kardashev level one. It would be early molecular manufacturing capability or good high volume carbon nanotube and graphene capabilities. The amount of material would be about 20,000 times less than the surface area of the earth or about 10,000 square miles.

SOURCE : Arxiv, wikipedia

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