New idea for Dyson sphere proposed

March 30, 2015 by Bob Yirka weblog
A Dyson Sphere with 1 AU radius in Sol system. Credit: arXiv:1503.04376 [physics.pop-ph]

(Phys.org)—A pair of Turkish space scientists with Bogazici University has proposed that researchers looking for the existence of Dyson spheres might be looking at the wrong objects. İbrahim Semiz and Salim Oğur have written a paper and uploaded it to the preprint server arXiv, in which they suggest that if an advanced civilization were to build a Dyson sphere, it would make the most sense to build it around a white dwarf.

The popularization of the idea for a Dyson sphere came about when physicist Freeman Dyson published a paper back in the 60's outlining the idea of an advanced civilization building a sphere around a star to capture its energy for its own use. The idea has been popularized in science fiction and has grabbed the attention of real life researchers who suggest that if a Dyson sphere could be detected, it would present strong evidence for the existence of an advanced extraterrestrial civilization of some sort.

Over time, Dyson and other scientists have found that the massive amount of material needed to build such a sphere would be untenable, thus, a more likely scenario would be a civilization building a ring of energy capturing satellites which could be continually expanded.

But the notion of the sphere persists and so some scientists continue to look for one, believing that if such a sphere were built, the process of capturing the energy from the interior sun would cause an unmistakable infrared signature, allowing us to notice its presence. But thus far, no such signatures have been found. That might be because we are alone in the universe, or, as Semiz and Oğur argue, it might be because we are looking at the wrong types of stars. They suggest that it would seem to make more sense for an advanced civilization to build their sphere around a white dwarf, rather than a star that is in its main sequence, such as our sun—not only would the sphere be smaller (they have even calculated an estimate for a just one meter thick—1023 kilograms of matter) but the gravity at its surface would be similar to their home planet (assuming it were similar to ours).

Unfortunately, if Semiz and Oğur are right, we may not be able to prove it for many years, as the luminosity of a white dwarf is much less than other stars, making it extremely difficult to determine if the infrared signal is natural, or if it has been altered by aliens.

Explore further: The strange case of the missing dwarf

More information: Dyson Spheres around White Dwarfs, arXiv:1503.04376 [physics.pop-ph] arxiv.org/abs/1503.04376

Abstract
A Dyson Sphere is a hypothetical structure that an advanced civilization might build around a star to intercept all of the star's light for its energy needs. One usually thinks of it as a spherical shell about one astronomical unit (AU) in radius, and surrounding a more or less Sun-like star; and might be detectable as an infrared point source.
We point out that Dyson Spheres could also be built around white dwarfs. This type would avoid the need for artificial gravity technology, in contrast to the AU-scale Dyson Spheres. In fact, we show that parameters can be found to build Dyson Spheres suitable —temperature- and gravity-wise— for human habitation. This type would be much harder to detect.

via TechnologyReview

Related Stories

The strange case of the missing dwarf

February 18, 2015

The new SPHERE instrument on ESO's Very Large Telescope has been used to search for a brown dwarf expected to be orbiting the unusual double star V471 Tauri. SPHERE has given astronomers the best look so far at the surroundings ...

Could we harvest energy from a star?

February 4, 2014

Our civilization will need more power in the future. Count on it. The ways we use power today: for lighting, transportation, food distribution and even entertainment would have sounded hilarious and far fetched to our ancestors.

Are aliens watching old TV shows?

January 20, 2015

You've probably heard the trope about how aliens have been watching old episodes of "I Love Lucy" and might think these are our "historical documents". How far have our signals reached?

Exploded star blooms like a cosmic flower

February 12, 2015

Because the debris fields of exploded stars, known as supernova remnants, are very hot, energetic, and glow brightly in X-ray light, NASA's Chandra X-ray Observatory has proven to be a valuable tool in studying them. The ...

Recommended for you

Quantum internet goes hybrid

November 22, 2017

In a recent study published in Nature, ICFO researchers led by ICREA Prof. Hugues de Riedmatten report an elementary "hybrid" quantum network link and demonstrate photonic quantum communication between two distinct quantum ...

Enhancing the quantum sensing capabilities of diamond

November 22, 2017

Researchers have discovered that dense ensembles of quantum spins can be created in diamond with high resolution using an electron microscopes, paving the way for enhanced sensors and resources for quantum technologies.

Study shows how to get sprayed metal coatings to stick

November 21, 2017

When bonding two pieces of metal, either the metals must melt a bit where they meet or some molten metal must be introduced between the pieces. A solid bond then forms when the metal solidifies again. But researchers at MIT ...

Imaging technique unlocks the secrets of 17th century artists

November 21, 2017

The secrets of 17th century artists can now be revealed, thanks to 21st century signal processing. Using modern high-speed scanners and the advanced signal processing techniques, researchers at the Georgia Institute of Technology ...

26 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

antialias_physorg
4.9 / 5 (9) Mar 30, 2015
But thus far, no such signatures have been found. That might be because we are alone in the universe, or, as Semiz and Oğur argue, it might be because we are looking at the wrong types of stars.

Or it might be because building something like this is stupid?
If you want to live on a surface you need gravity to hold you down on that surface. Unless these aliens also have universal gravity generating machines a Dyson sphere will not have that. Even a spinning Dyson sphere will have that "target" gravity only at the equator and nowhere else.

In the end the Dyson sphere argument boils down to energy. Even our (rather primitive) tech already shows a trend towards more efficiency. Energy is already super-abundant if only a very small amount of the solar radiation is tapped. Dyson spheres posit that aliens need a lot more energy than we do (and have no way of creating energy on the spot through fusion or even better means) - and that makes no sense at all.
mathewbinkley
5 / 5 (1) Mar 30, 2015
I had the same idea a couple of years ago, and I'm glad to see someone run with it. My work (back of the envelope stuff, not nearly as refined as theirs) is below.

binkley.accre.vanderbilt.edu/dyson-planet.pdf
gkam
3 / 5 (4) Mar 30, 2015
Superman and Scrooge McDuck are more likely to be materialized than this scientology-scale idea.
Scottingham
5 / 5 (2) Mar 30, 2015
I'm totally with you. However, I wonder if there are some really kick-ass applications of stupid-high amounts of energy that we have no idea of at this point on our technological trajectory. Perhaps conversion of energy to mass is particularly useful in creating artificial gravity or something.

Also, I don't think they'd be 'living' on the sphere, I always thought it'd beam the energy to where they are currently residing.
nkalanaga
4.4 / 5 (7) Mar 30, 2015
A Dyson sphere around a white dwarf wouldn't look anything like a white dwarf. It would resemble a brown dwarf, but be much larger than even those. It would would be vastly larger than a white dwarf, which is about the diameter of Earth, and would emit energy almost entirely in the infrared.

As for gravity, one built around a white dwarf would have surface gravity everywhere, because the mass of the white dwarf would provide it. A Dyson sphere with a radius of about 3.7 solar radii, about 2,500,000 kilometers, around a WD with 0.5 solar masses, would have a surface gravity roughly equal to Earth's. One built around a Sun-like star, on the other hand, would have no significant surface gravity, due to its large radius.
Jeffhans1
4.2 / 5 (5) Mar 30, 2015
As for gravity, one built around a white dwarf would have surface gravity everywhere, because the mass of the white dwarf would provide it. A Dyson sphere with a radius of about 3.7 solar radii, about 2,500,000 kilometers, around a WD with 0.5 solar masses, would have a surface gravity roughly equal to Earth's. One built around a Sun-like star, on the other hand, would have no significant surface gravity, due to its large radius.


Now imagine you take your idea one step further and use a lower mass black hole as the gravity and mass conversion energy creating process and put an earth normal gravity layer shell to absorb the radiation and protect the inhabitants. You could then make the whole thing look like a gas giant to help radiate the heat from your civilization. It would also make it very hard to locate your planet from an outsiders point of view.
antialias_physorg
not rated yet Mar 30, 2015
nm

gjbloom
2 / 5 (2) Mar 30, 2015
Now imagine you take your idea one step further and use a lower mass black hole as the gravity and mass conversion energy creating process and put an earth normal gravity layer shell to absorb the radiation and protect the inhabitants. You could then make the whole thing look like a gas giant to help radiate the heat from your civilization. It would also make it very hard to locate your planet from an outsiders point of view.


One other advantage of using a low-mass black hole for your energy supply would be that you can adjust the energy production to suit your needs. If a mega-scale engineering project needs extra juice, you simply trim the mass-feed into your low-mass black hole and allow it to radiate down to a suitably smaller mass, then capture the much higher energy output. When your project is complete, you simply throw some extra mass into the black hole to damp it back down to a more comfortable level.
Sigh
not rated yet Mar 30, 2015
In the end the Dyson sphere argument boils down to energy. Even our (rather primitive) tech already shows a trend towards more efficiency. Energy is already super-abundant if only a very small amount of the solar radiation is tapped. Dyson spheres posit that aliens need a lot more energy than we do (and have no way of creating energy on the spot through fusion or even better means) - and that makes no sense at all.

I think it might. Why build fusion reactors if you've already got one running, in the form of a star? And if you live in a virtual universe, it gets bigger the more computing power you have, which needs energy. Of course, then you don't care about gravity, and can optimise the radius of the Dyson sphere for energy capture.
Dethe
1.7 / 5 (6) Mar 30, 2015
Dyson sphere is a silly sci-fi concept of 50's - the really advanced civilizations would utilize the cold fusion or overunity devices for production of energy at the place of its consumption. Any speculations about it is just a waste of tax payers money dedicated for research of really useful stuffs.
TheGhostofOtto1923
1.7 / 5 (3) Mar 30, 2015
What - nobody here has read niven? A sphere could be spun and 'people' could live on the interior, at the equator. Sure it wold be hard to stabilize. But they probably wont find spheres or rings because the machines which naturally evolve from organic intelligence such as ours wont need all that energy or space.

If they want to conserve energy for the long term perhaps they would collapse a portion of their system mass and feed matter into it in a controlled manner. There must be a way of doing this. Google 'black hole farming' for some examples not worth repeating.

Of course they would drain mass off of their sun until the wasteful and inefficient nuclear fire goes out. Machine singularities may as a result be completely dark.
Superman and Scrooge McDuck are more likely to be materialized than this scientology-scale idea
-Bet you wish you had something mayure and knowledgable to say eh?
antialias_physorg
4.5 / 5 (2) Mar 30, 2015
Of course, then you don't care about gravity, and can optimise the radius of the Dyson sphere for energy capture.

Total energy captured is independent of size of the sphere.

Why build fusion reactors if you've already got one running, in the form of a star?

Because building a fusion reactor is a tad less work than building a Dyson sphere?
Even if you build a Dyson sphere around a dwarf. What do you do about CMEs? What do you do about radiation shielding? A 1 meter thick support isn't going to shield you at that close a distance.

As for the article and its point about an energy signature. IF such a sphere can be built - why would they assume such a sphere would radiate energy evenly? Construction of heat moving systems (and possibly limiting the number of heat expulsion sittes - e.g. to the poles) would mean the signature could be basically anything: From invisible at some directions to intense polar jets.
FainAvis
4.3 / 5 (6) Mar 31, 2015
Otto: You are super critical of anyone else who comes up with a daft idea, even to the point of being a dastardly bully.
I'm with gkam's comment on this. More likely that Superman or Scrooge will materialize than your silly idea.
cjn
5 / 5 (1) Mar 31, 2015
I feel like the Dyson Sphere is a concept that reflects the bias our human perspective puts on how we think other civilizations will advance technologically. We are understandably fixated with the idea of living on a rock around a star, but I doubt that investing the amount of resources necessary to envelope and harness a single star is a rational approach when there are a hundred billion galaxies, each with hundreds of billions of stars.

I suppose, if one cannot travel beyond the speed of light, suitable systems are very few and far between, or the cost of space exploration too great for its ROI, then maybe investing heavily in a the development of a single star may be a reasonable approach. But again, this is a very "human" thought process, and may not be common -for it may be difficult to comprehend just what type of efforts another civ could use this scale of energy to accomplish.
TheGhostofOtto1923
2.3 / 5 (3) Mar 31, 2015
Otto: You are super critical of anyone else who comes up with a daft idea, even to the point of being a dastardly bully.
I'm with gkam's comment on this. More likely that Superman or Scrooge will materialize than your silly idea.
Gkam is an ass whose is compelled to post whether he has anything relevant to say or not, and subsequently litters these threads with empty comments. Gkam also makes up his own facts and lies about his qualifications in order to support them.

It is certainly not bullying to object to his litter and expose his lies, and that's what I'm doing. The people who care about the quality of this site, and who respect honesty and integrity in general, should do the same.

But then who cares what you think?
antialias_physorg
5 / 5 (1) Mar 31, 2015
We are understandably fixated with the idea of living on a rock around a star,

Very good point. Projecting technology into the future is always a bit difficult.
However I would think that developing tech that would let us live under any kind of condition via artificial bodies (and/or a significant extension of lifespans - if not downright quasi-immortality) will be achieved far earlier than the ability to create megastructures in space on the order of Dyson spheres.

...and once such artificial bodies/immortality is achieved then the idea of a Dyson sphere becomes moot. In the former case it's not needed...in the latter case birth rates would drop drastically to the point where such humongous living spaces aren't needed either.

I suppose, if one cannot travel beyond the speed of light, suitable systems are very few and far between,

If either of the above technologies come first then travel times become unimportant.
nkalanaga
3.7 / 5 (3) Mar 31, 2015
Jeffhans1, and others: That has been seriously suggested, and does have advantages, IF one can find low-mass black holes. Feed matter to the hole, then capture the released energy, which some estimates say could be as much as half the mass-energy of whatever falls in.

antialias_physorg: White Dwarfs are dead. No fusion, no flares, no CMEs. Unless they're hit by something, they just sit there, radiating away their stored heat. They wouldn't give off much energy above ultraviolet, and that's easily stopped by a meter of solid matter.

For a WD the diameter of the Earth, at a temp of 10,000 K, the habitable zone is about 4.6 MKms. So, one would need a more massive WD, a cooler WD, a way of dissipating excess heat, or make do with lower gravity. None of those would be difficult compared with building the thing in the the first place.
Sigh
5 / 5 (1) Apr 01, 2015
Of course, then you don't care about gravity, and can optimise the radius of the Dyson sphere for energy capture.
Total energy captured is independent of size of the sphere.

Sure, but material needed is not. And if efficiency depends on temperature gradient, then the size of the sphere matters.

Why build fusion reactors if you've already got one running, in the form of a star?

Because building a fusion reactor is a tad less work than building a Dyson sphere?

One reactor, sure, but nobody would even consider a Dyson sphere unless vast amounts of energy were called for, and a corresponding number of reactors. How much fuel would that number of reactors need? Where would you get it from? For how long do you want the system to work? Seeing we have no idea how a functioning fusion reactor would look, and what the economics are like using technology we don't have, I don't think we can say reactors make more sense than a Dyson sphere. We just don't know.
antialias_physorg
5 / 5 (2) Apr 01, 2015
but nobody would even consider a Dyson sphere unless vast amounts of energy were called for

Exactly. The point is: Why would such vast amounts be called for? Certainly no (planet) evolved life form needs that amount of power (per square meter) or it could not have evolved.
Technology also doesn't need that amount of power spread over a wide surface.

If you're an alien society and actually need the power output of a star for some specific purpose then you need a concentrator - and that can be done without resortung to megastructures.

The current idea of Dyson spheres is thatthey provide a place for organics to live on or a power source for large computational facilities. For both the power needs seem VASTLY overblown.
nkalanaga
5 / 5 (2) Apr 02, 2015
The biggest problem with a Dyson Sphere seems to have been overlooked. Never mind the cost, or the amount of material needed, or why one would want the thing. Just like Ringworld, hollow spheres with stars inside are unstable. There's nothing to keep the star centered, and once it drifts even a little bit off-center, for any reason, it will continue to move until it hits the inside of the sphere. Some form of dynamic stability system, in other words a propulsion system, would be need to keep the system stable.

Niven's Ringworld used fusion engines, fueled by solar flares and mass ejections. White dwarfs don't flare, and don't have enough atmosphere for CMEs, so that won't work. Also, since the sphere can drift in any direction, it will require rockets every few degrees over the entire surface, which could make it hard to hold an atmosphere. Without "magic" the things won't work.
nkalanaga
5 / 5 (1) Apr 02, 2015
For those who really want to dig into Dyson spheres, this seems to be a good place to start.

http://www.aleph....FAQ.html

It seems that the original idea was NOT a rigid sphere, but to completely surround the star with orbiting habitats and solar collectors. That idea is stable, as the individual objects are in normal Keplerian orbits, and is easy to build, requiring only a LOT of work. In theory, we could start today.
Captain Stumpy
not rated yet Apr 02, 2015
... vast amounts of energy were called for
Not sure that it makes sense to commit the massive amount of resources to build a dyson sphere when the same amount of material can likely be used to create enough fusion reactors that may surpass even the amount of energy captured by the dyson sphere... and then there is nkalanga's point
There's nothing to keep the star centered
Maybe someone should work out the amount of resources we KNOW will be needed then try to figure out the amount of resources to build a fusion reactor
Take those numbers and work out whether it would even make sense to TRY to build a dyson sphere or just a sh*t load of reactors (my money is on the latter, plus, it adds to the redundancy)
It makes FAR more sense that the redundancy of multiple fusion sources is created than a single sphere that would be catastrophic when/if there was a failure

Time, $$, resources, ability, redundancy, Ease, mobility, functionality=no sphere IMHO
Captain Stumpy
not rated yet Apr 02, 2015
... I don't think we can say reactors make more sense than a Dyson sphere
@sigh
i see your point about that but it is FAR more logical to assume that most of the resources used in fusion reactors will be similar to fission ones, with some caveat's like the AM control of the plasma, and a few other things... so we CAN take a rough ballpark figure and go from there

this is similar to the rough ball park figure being used to the Dyson Sphere ... we don't know that the thickness of the sphere will be enough to withstand the various pressures from the star inside and then the additional object strikes outside... so it would have to be of a considerable thickness to withstand both but also to take the gravity and other (manufacturing) pressures

Then there is the amount of energy actually absorbed vs output
I still think multiple reactors is FAR more feasible AND logical
slightly anthropomorphic i know, and tech could FAR surpass ours, true, but still
it's IMHO anyway
Eikka
5 / 5 (1) Apr 04, 2015

Exactly. The point is: Why would such vast amounts be called for? Certainly no (planet) evolved life form needs that amount of power (per square meter) or it could not have evolved.


You don't know what they'll need the energy for. Certainly you don't need it if you're content on existing as little ants on the surface of a rock ball, living or dying at the whim of the universe.

A civilization that attempts to build a dyson sphere probably has some good use for it, like trying to bend space to create wormholes, or simulate an entire universe from the quantum level up etc.
phprof
1 / 5 (1) Apr 04, 2015
This is stupid. A very interesting idea but it suffers from a major flaw. Who cares? We need useful fusion before one even cares about a Dyson Sphere. If they have the tech to build such a structure they could just show up and enslave us.
Urgelt
3 / 5 (2) Apr 06, 2015
Dyson spheres require truly vast structural strength to hold together at the poles. Spinning them only balances gravity at the equator. I think it's a waste of time to bother looking for any at all.

A much more practical design, suggested by Larry Niven, is a solid rotating ring. It takes less material to construct one - though it's still a lot - and needs much less structural strength than a Dyson sphere. You can obtain simply enormous amounts of living space from a ring design. Niven's ringworld is a million miles wide with a circumference of 600 million miles - all of it filled with atmosphere on the inner surface and a standard 'gravity' from centrifugal force. That's a lot of room.

It would be tricky to detect one, though. If the sun is occluded by the ring from our line of sight, we won't see much. If it isn't, we won't notice the ring. A partial occlusion might be detectable, but we shouldn't expect variable luminosity to give it away.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.