Type III Societies (Apparently) Do Not Exist

Abstract

Whether technological societies remain small and planet-bound like our own, or ultimately span across galaxies is an open question in the Search for Extraterrestrial Intelligence. Societies that engineer on a galactic scale are classified as Type III on Kardashev's scale. I argue that Type III societies can take the form of blackboxes, entire galaxies veiled in an opaque screen. A blackbox has a temperature that is just above that of the cosmic microwave background, for the maximum possible thermodynamic efficiency. The screen can be made from artificial dust pervading the galaxy, establishing feedback on the diffuse interstellar medium itself. I show that there is enough material in galaxies to build blackboxes if the dust is fashioned into dipole antennas, especially if they are made of carbon nanotubes.The thermal emission of a blackbox makes it a bright microwave source. I examine the Planck Catalog of Compact Sources (PCCS2) to constrain the abundance of blackboxes. None of the 100 GHz sources has the spectrum expected of a blackbox. The null result rules out shrouded galaxy clusters out to z ≈ 1 and shrouded Milky Ways out to (comoving) 700 Mpc. The reach of the results includes 3 million galaxies containing an estimated 300 quadrillion terrestrial planets, as well as tens of thousands of galaxy clusters. A more detailed search of the PCCS2 can find or rule out blackboxes in 30 million galaxies, and the South Pole Telescope Sunyaev-Zeldovich survey can search another 20 million galaxies.Combined with the null results from other searches for Type III societies, I conclude that they are so rare that they basically do not exist within the observable Universe. A hypothesis of "Cosmic Pessimism" is discussed, in which we are alone, our long-term chances for survival are slim, and if we do survive, our future history will be checkered. Our loneliness is suggested by the lack of Type III societies. I discuss the remaining forms of Type III societies not yet well constrained by observation. I argue that the ease of building blackboxes on planetary and Solar System scales may lead, within a few centuries, to environmental catastrophes vastly more devastating than anything we are doing now, boding ill for us.

The Log Log Prior for the Frequency of Extraterrestrial Intelligences

“…The recent Ĝ survey has a reach of ∼ 0.9 (Griffith et al 2015). Similar reaches are achieved by surveys for Type II radio beacons (Horowitz & Sagan 1993) and very cold waste heat from Type III societies (Lacki 2016), and from the observation that intergalactic travelers are not here (Olson 2015). Furthermore, Type III societies are presumably long-lived simply because it takes so much time to cross a galaxy and engineer it (Kardashev 1985;Wright et al 2014b;Zackrisson et al 2015;Lacki 2016).…”

“…SETI has sought evidence for extraterrestrials through many programs and an increasing number of methods, from the traditional surveys for radio broadcasts (e.g., Tarter 1985;Blair et al 1992;Horowitz & Sagan 1993;Anderson et al 2002;Gray & Ellingsen 2002;Siemion et al 2010), to searches for laser light (Shvartsman et al 1993;Reines & Marcy 2002;Howard et al 2004;Hanna et al 2009;Borra 2012), high energy radiation (Harris 2002; see also Learned 1994;Corbet 1997;Lacki 2015), extraterrestrial technology in the Solar System (Freitas 1983;Steel 1995), artificial "megastructures" the sizes of planets (Arnold 2005;Wright et al 2016;Boyajian et al 2016) or star systems (Slysh 1985;Timofeev et al 2000;Jugaku & Nishimura 2004;Carrigan 2009;Villarroel et al 2016), and the engineering of entire galaxies (Kardashev 1964;Annis 1999;Wright et al 2014a;Griffith et al 2015;Zackrisson et al 2015;Lacki 2016). But so far, no alien societies have been found yet, and there is no consensus about what that means (Brin 1983;Ćirković 2009).…”

Dyson Spheres

“…His approach was general, but many other analyses of the gravitational, radiative, and thermodynamic properties of Dyson spheres invoke specific geometries, purposes, energy generation schemes, or other activities for the Dyson spheres. Some examples are studies of the gravitational dynamics of monolithic rings around stars (McInnes 2003;Rippert 2014, and references therein), the Harrop-Dyson satellite that exploits solar wind particles instead of photons (Harrop & Schulze-Makuch 2010), spheres with an inside surface temperature near 300K (Badescu 1995), much hotter and smaller Dyson spheres that radiate in the optical (Osmanov & Berezhiani 2018), analyses of very cold Dyson spheres (Lacki 2016), and partial shells used for stellar propulsion or energy extraction (Badescu & Cathcart 2000, 2006. Studies have also examined Dyson spheres around white dwarfs (Semiz & Ogur 2015), neutron stars (Osmanov 2016), black holes (Inoue & Yokoo 2011;Opatrný et al 2017), and X-ray binaries (Imara & Di Stefano 2018).…”

“…The first observational search for galaxy-wide populations of Dyson spheres was that of Annis (1999a), who examined a sample of over 100 galaxies of similar distance to search for any that were optically underluminous, consistent with a significant amount of starlight blocked by Dyson spheres. Griffith et al (2015) used the WISE all-sky survey to search for resolved sources of extended infrared emission to search for populations of Dyson spheres by their waste heat, and Lacki (2016) used Planck data to put upper limits on galaxies with all of their starlight being reprocessed to very low temperatures. Zackrisson et al (2015) combined these strategies, searching for optically underluminous galaxies and following up with infrared measurements to identify the whether "missing" luminosity was being emitted there.…”

Sunscreen: Photometric Signatures of Galaxies Partially Cloaked in Dyson Spheres

“…First, would waste-heat appear in a visible form? Maybe the aliens maintain their artifacts at a non-Earthly temperature -if it's between ∼ 10-100 K (glowing in far-infrared) or 600 K, the waste heat would not have been found yet (Lacki 2016; see also Bradbury 2000;Osmanov & Berezhiani 2018). Perhaps they broadcast it in neutrinos or some other nigh-undetectable particle, or beam it anisotropically away from us 1 , or dump it into black holes.…”