Freeman Dyson hypothesized the vast structures 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.
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: “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).
The Dyson Sphere Hypothesis is an extrapolation of 1950s technologies and theories that claim that advanced societies will need more and more energy, spouting radiation and radio waves all over the place. Dyson theorized that civilizations as they grew should be detectable in the infrared radiation range, the waste heat being the thing that is the signature of a Kardashev II civilization.
Little did we realize then that as our technology advanced, it required less and less energy to supply it, and that’s not counting digital technology that doesn’t broadcast out into the Cosmos!
So is looking for Dyson Spheres/Swarms a waste of time? I don’t think so. Simply because of the fact that aliens by large might not think like humans and some might prefer a brute force approach of providing their civilizations the energy they require.
Plus stellar archaeology is cool!
Rendevous With Rama, a 1972 novel written by Sir Arthur C. Clarke, is about an asteroid sized alien starship that enters the Solar System in the 22nd Century. A human spaceship crew enters and explores the huge vessel and has to leave when the crew discovers the ship is heading toward the Sun, apparently toward its doom.
The ship doesn’t destroy itself however. Instead it extends a filament into the Sun’s corona and draws the Sun’s material into itself; thus rebuilding losses incurred while traveling immense distances between the stars.
Below is a supposed photo by the NASA Solar Dynamic Observatory of a phenomenon doing just that. And it’s not just a Rama-sized asteroid object, it’s a stellar sized Death Star object!
Stellar Filament or Death Star Refueling?
I know I posted something like this a couple of years ago, but this is an updated video from the NASA SOHO spacecraft orbiting our Sun.
Take a good look. Are they alien spacecraft, or just photographic “artifacts” as NASA purports?
You be the judge.
Larry Klaes of the Tau Zero Foundation writes at the Centauri Dreams blog about how “explosive” the Universe really is and how we perceive the twinkling lights in the sky as a peaceful, beautific scene is severely flawed:
When we look up at the night sky with our eyes alone, everything about it seems calm and even peaceful. Aside from a passing airplane or satellite, only the occasional meteor or twinkling star indicate any natural activities up there. Otherwise, the Universe seems almost immobile and permanent, even when we watch the stars for a long while.
Recent news by the astronomy community shows just how much of an illusion this perception actually is. On May 14, NASA announced the discovery of the youngest local supernova remnant yet known, an object unpoetically known as G1.9+0.3, located near the center of our Milky Way galaxy about 26,000 light years from Earth.
Though most stars exist for ages far longer than human minds can conceive, they are not immortal. Some last for billions of years and eventually more-or-less quietly fade away; this will be the fate of our Sun.
More massive suns do not exist for quite so long, nor do they leave the Universe peacefully. These natural fusion reactors often end up in a titanic explosion called a supernova. Some lose their nuclear fuel, causing their cores to collapse and release huge amounts of energy in the process, leaving a neutron star or black hole in their wake. Other large suns that are part of a binary system where one star is a white dwarf create their death act when too much material from the giant star is pulled onto the white dwarf companion, causing its core to heat enough to create runaway nuclear fusion and tear itself apart.
White dwarf stars are not only formed in binary systems, main sequence single stars such as F, G and K types are capable as well. When these stars age, they use up most of their hydrogen fuel. Our sun is a type G, so it is theorized that as it ages and uses up its fuel, it will swell in size as it tries to fuse heavier elements like helium and lithium. The core starts to get more dense as it converts the heavier fuels into heavier yet materials, but the surrounding gas envelop expands. Eventually, the sphere will gulp down Mercury, Venus, Earth, Mars, Jupiter and eventually Saturn as it enters its red giant phase:
As a red giant, the Sun will have a maximum radius beyond the Earth’s current orbit, 1 AUm), 250 times the present radius of the Sun. However, by the time it is an asymptotic giant branch star, the Sun will have lost roughly 30% of its present mass due to a stellar wind, so the orbits of the planets will move outward. If it were only for this, Earth would probably be spared, but new research suggests that Earth will be swallowed by the Sun due to tidal interactions.
Eventually the Sun will “blow” off the outer gas layers in a “semi-nova” (because it’s not massive enough to collapse into a full nova) and a white dwarf star will result.
Of course by then I fully expect the Solar System to be empty of life, either by Exodus, Diaspora, already extinct or transcension by Singulary(s) (or other means).
The Universe is an interesting, and violent place.
Even our own little corner of it has that “take a walk on the wild side” quality!