III. Ecosmos: A Revolutionary Fertile, Habitable, Solar-Bioplanet, Incubator Lifescape

5. ExoUniverse Studies: Detectable Presence, Conceptual Features

			This is a current “multiverse image” that can be found on Google, there attributed to Florida State University. When I began this long project in the 1960s a point of cosmic origin was not even known, starry galaxies found a few decades earlier. In the later 2010s, a sign of worldwide scientific progress is an ability to perceive and quantify an infinite constellation of stochastic cosmoses. This 2015 section will collect and report upon theoretical entries which consider other universes with regard to parameters and propensities which may or may not foster living entities like us. A nascent aspect is a glimmer of ways to detect their actual presence. We include extended Abstracts of expertise and technical vernacular as our infinitesimal but valiant Earth intelligence may begin to sense, gain and fulfill infinite promise.

While inklings of other cosmoses were broached through history (Siegfried), actual theoretical studies have only been possible into the 2010s by way of cumulative global postings. For a contrast, I heard Andrei Linde present his fractal multiverse theory in 1983 by way of overhead slides, in 2015 Fred Adams could show streaming videos of galactic evolution. Recent papers by Adams and colleagues, Sandora McCullen, and others can consider an entire unitary cosmos to see how varying physical parameters and chemical elements might effect their relative lifetime and habitability. And ever again, how fantastic is it that we sentient beings on a tiny but special bioplanet are altogether able to contemplate and quantify on a scale of whole cosmoses?

2020: In 1983 I attended Andrei Linde’s first US public lecture at Harvard where he spoke of bubbling fractal universes. But as the 21st century began, cosmic multitudes beyond our own remained a theoretical conjecture. Into the 2010s, due to Fred Adams, McCullen Sandora and other seekers, deeper insights along with detectable inklings now indicate a vast array of vicarious universes. Several entries consider whole cosmoses with regard to variable parameters and elemental makeup. As a result this infinity (maybe 10500) are thought to span wide contingent ranges to an extent that again some selective process may be going on. Since we Earthlings are here due to a rarest cocatenation, our home spacescape must favor anthropic qualities. But how fantastic is it that in a few centuries a sentient worldly species on a tiny orb some 10-33 orders smaller can yet explore and achieve such vast knowledge.

Adams, Fred C.. The Degree of Fine-Tuning in our Universe – and Others. arXiv:1902.03928.
Alonso-Serrano, Ana, et al, eds. The Multiverse. Universe. July, 2019.
Baumgartner, Sandra and Jaiyul Yoo. Living in a Non-Flat Universe. arXiv:2205.12973.
Elhatisari, Serdar, et al. Alpha-alpha Scattering in the Multiverse. arXiv:2112.09409.
Horndeski, Gregory. The Multiverse and Cosmic Procreation via Cofinsler Spaces: Being or Nothingness. arXiv:2301.10275
Kartvelishvili, Guram, et al. The Self-Organized Critical Multiverse. arXiv:2003.12594.

Masaki, Shogo, et al. Anisotropic Separate Universe Simulations. arXiv:2003.10052.
Mastromarino, Claudio, et al. Properties and Observables of Massive Galaxies in Self-Interacting Dark Matter Cosmologies. arXiv:2212.01403.
Sandora, McCullen, et al. Multiverse Predictions for Habitability: Element Abundances. arXiv:2302.10919.
Siegfried, Tom. The Number of the Heavens, Cambridge: Harvard University Press, 2019.
Vidotto, Francesca. Time, Space and Matter in the Primordial Universe. arXiv:2207.13722.
Wood, Charlie. Why This Universe?. Quanta. November 17,, 2022.

2023:

Adams, Fred. Constraints on Alternative Universes: Stars and Habitable Planets with Different Fundamental Constants. arXiv:1511.06958. The University of Michigan astronomer and author has been a leader of these frontier journeys to distant cosmic spacescapes.

This paper develops constraints on the values of the fundamental constants that allow universes to be habitable. We focus on the fine structure constant α and the gravitational structure constant αG, and find the region in the α-αG plane that supports working stars and habitable planets. This work is motivated, in part, by the possibility that different versions of the laws of physics could be realized within other universes. The following constraints are enforced: [A] long-lived stable nuclear burning stars exist, [B] planetary surface temperatures are hot enough to support chemical reactions, [C] stellar lifetimes are long enough to allow biological evolution, [D] planets are massive enough to maintain atmospheres, [E] planets are small enough in mass to remain non-degenerate, [F] planets are massive enough to support sufficiently complex biospheres, [G] planets are smaller in mass than their host stars, and [H] stars are smaller in mass than their host galaxies. This paper delineates the portion of the α-αG plane that satisfies all of these constraints. The results indicate that viable universes --- with working stars and habitable planets --- can exist within a parameter space where the structure constants α and αG vary by several orders of magnitude. (Abstract)

Adams, Fred and Evan Grohs. On the Habitability of Universes without Stable Deuterium. Astroparticale Physics. 91/90, 2017. We added this new section to report entries like this which show how it has now become possible for human beings to contemplate entire cosmoses. Also posted at arXiv:1612.04741, here University of Michigan astrophysicists consider if a deficit of deuterium, one of two hydrogen isotopes, would affect an ability to form a modicum of living entities. Upon a natural philosophy reflection, incredulous to a Newton or Galileo, there must be some grand significance and purpose for our collaborative humankinder acumen to be able to quantify such multiUniVerse reaches.

In both stars and in the early universe, the production of deuterium is the first step on the way to producing heavier nuclei. If the strong force were slightly weaker, deuterium would not be stable, and many authors have noted that nuclesynthesis would be compromised so that helium production could not proceed through standard reaction chains. Motivated by the possibility that other regions of space-time could have different values for the fundamental constants, this paper considers stellar evolution in universes without stable deuterium and argues that such universes can remain habitable. With stars evolving through gravitational contraction, explosive nucleosynthesis, the triple-nucleon reaction, and the CNO cycle, universes with no stable deuterium are thus potentially habitable, contrary to many previous claims. (Abstract excerpts)

Adams, Fred and Evan Grohs. Stellar Helium Burning in Other Universes: A Solution to the Triple Alpha Fine-Tuning Problem. arXiv:1608.04690. In these days of multiverse studies, a University of Michigan physicist and an astronomer enlist a new parameter by which a relative cosmic habitability might be quantified. As the Abstract notes this involves a nuance upon relative propensities to make carbon atoms vital for life and evolution. And might we then wonder for what reason can sapient creatures on a tiny ovular world be able to lately survey and quantify such infinite vistas?

Motivated by the possible existence of other universes, with different values for the fundamental constants, this paper considers stellar models in universes where 8Be is stable. Many previous authors have noted that stars in our universe would have difficulty producing carbon and other heavy elements in the absence of the well-known 12C resonance at 7.6 MeV. This resonance is necessary because 8Be is unstable in our universe, so that carbon must be produced via the triple alpha reaction to achieve the requisite abundance. This paper focuses on stellar models that burn helium into beryllium; once the universe in question has a supply of stable beryllium, carbon production can take place during subsequent evolution in the same star or in later stellar generations. Using both a semi-analytic stellar structure model as well as a state-of-the-art stellar evolution code, we find that viable stellar configurations that produce beryllium exist over a wide range of parameter space. Finally, we demonstrate that carbon can be produced during later evolutionary stages. (Abstract excerpts)

This paper argues that the sensitivity of our universe — and others — to the triple alpha reaction for carbon production is more subtle and less confining than previously reported. If nuclear structures are different in other universes, so that the carbon resonance is not present at the proper energy level, then previous work has shown that carbon production through this process can be highly suppressed. If the nuclear structures are different, however, then it remains possible for the isotope 8Be to be stable in other universes. In such universes with long-lived 8Be, carbon production can proceed without the need for the triple alpha process, or the need for any particular resonance. (29)

Adams, Fred C.. The Degree of Fine-Tuning in our Universe – and Others. arXiv:1902.03928. In a 212 page paper to appear in Physics Reports, the collegial University of Michigan astrophysicist (search) enters a broad and deep mathematical survey to date of a stochastic infinity of exo-cosmoses. Its sections go from Particle Parameters, Cosmological Features, Dark Energy, Big Bang Nucleosynthesis, to Galactic Structures, Stellar Evolution, Solar Planets, and more. The main theme is the contingency of this temporally unfolding universe, and myriad vicarious others, with regard to how they might permit living, developmental systems. A conclusion is that while particle values are sharply tuned, astrophysical vistas allow a wider space (wiggle room). A general surmise so far is that our universe with sapient observers may be a better or maximal case. One might note that such witnesses apply J. A. Wheeler’s participatory model whence any extant cosmos requires an internal self-recognition to attain full existence. See also concurrent papers by McCullen Sandora herein.

Both fundamental constants that describe the laws of physics and cosmological parameters that determine the cosmic properties must fall within a range of values in order for the universe to develop astrophysical structures and support life. This paper reviews current constraints on these quantities. The standard model of particle physics contains both coupling constants and particle masses, and the allowed ranges of these parameters are discussed. We then consider cosmic parameters, including the total energy density, vacuum energy density, baryon-to-photon ratio, dark matter contribution, and the amplitude of primordial density fluctuations. These quantities are constrained by the requirements that the universe lives for a long time, emerges from the BBN epoch with an acceptable chemical composition, and can produce galaxies.

On smaller scales, stars and planets must be able to form and function. The planets must be massive enough to maintain an atmosphere, small enough to remain non-degenerate, and support a complex biosphere. These requirements place constraints on the gravitational constant fine structure constant, and nuclear reaction rates. We consider specific instances of fine-tuning in stars, including the triple alpha reaction that produces carbon, and effects of unstable deuterium. For all of these issues, viable universes exist over a range of parameter space. (Abridged Abstract)

Adams, Fred, et al. Planets in Other Universes: Habitability Constraints on Density Fluctuations and Galactic Structure. arXiv:1505.06158. As a worldwide cerebral collaboration takes leave of our own cosmos, a University of Michigan team of astronomer Adams, physicist Katherine Coppess, and mathematician Anthony Bloch theorize generic modes of galaxy formation, structure, and habitable zones. A celestial propensity or inhibition to form stable, conducive planetary solar systems can then be entertained. It is noted that our home Earth, whereupon life has evolved to a worldwide sapience capable of such imaginations, might be an optimum biosphere, worthy of “superhabitable” status. This is an inaugural posting for this section, along with Constraints on Alternative Universes, Simulating the Universe(s), and On Separate Universes.

Motivated by the possibility that different versions of the laws of physics could be realized within other universes, this paper delineates the galactic parameters that allow for habitable planets and revisits constraints on the amplitude Q of the primordial density fluctuations. Previous work indicates that large values of Q lead to galaxies so dense that planetary orbits cannot survive long enough for life to develop. Small values of Q lead to delayed star formation, loosely bound galaxies, and compromised heavy element retention. This work generalizes previous treatments: [A] We consider models for the internal structure of galaxies and find the fraction of galactic real estate that allows stable, long-lived planetary orbits. [B] We perform a large ensemble of numerical simulations to estimate cross sections for the disruption of planetary orbits due to interactions with passing stars. [C] We consider disruption due to the background radiation fields produced by the galaxies. [D] One consequence of intense galactic background radiation fields is that some portion of the galaxy, denoted as the Galactic Habitable Zone, will provide the right flux levels to support habitable planets for essentially any planetary orbit. (Abstract)

The results of this work indicate that habitable planets can survive in galaxies with a wide range of properties, and hence in a wide range of universes. In this current generalized treatment, however, more planets can survive for several reasons: [A] Galactic structures naturally include a wide range of stellar densities, with lower densities in the outer regimes that allow for habitable orbits to survive. [B] With the consideration of internal galactic structure, we can determine the fraction of solar systems that avoid disruption (rather than using an all-or-nothing approach). Because planets are thought to be common, and galaxies contain many solar systems, a galaxy (universe) can remain habitable with only a small fraction of its solar systems surviving (note that Figures. [C] Even planets that are stripped from their host stars can remain habitable if they reside within the Galactic Habitable Zone, i.e., the region of the galaxy where the galactic background radiation has the proper intensity to heat planets. (23)

Finally, we note that most considerations of alternate universes use the properties of our own universe as the baseline for comparison, often with an implicit assumption that our universe provides the best possible environment for the development of life. The results of
this paper call this assumption into question: With the right parameters, galaxies can support extensive Galactic Habitable Zones, where up to 20% of the stars, and hence up to 20% of all planets, reside within a radiation field comparable to the one the Earth receives from our Sun. Such galaxies – residing in universes with the right properties – could support more habitable planets than our own. Within our universe, Earth is often considered as the optimal planet for supporting a biosphere, but other planets could be even more favorable. This issue, which could be called superhabitability, should also be explored further. (24)

Akrami, Yashar, et al. Promise of Future Searches for Cosmic Topology. Physical Review Letters. 132/171501, 2024. We cite this entry by 15 cosmoscientists from the USA, Norway, Japan, the UK, Italy, France and Spain coordinated by the COMPACT Collaboration at Case Western Reserve University for its content about an overall shape to our temporal galactic panorama but also the very achievement itself that an infinitesimal planetary intelligence can yet imagine, explore and quantify such infinite reaches. Who are we valiant peoples to appear and contain these abilities, for what participatory purpose do we carry out this task of ecosmic self-description and observance?

The shortest distance around the Universe through us is unlikely to be much larger than the horizon diameter if microwave background anomalies are due to cosmic topology. We show that observational constraints from the lack of matched temperature circles in the microwave background leave many possibilities for such topologies. We evaluate the detectability of microwave background multipole correlations for sample cases. Searches for topology signatures in observational data over the large space of possible topologies pose a formidable computational challenge.

Alonso-Serrano, Ana and Gil Jannes. Conceptual Challenges on the Road to the Multiverse. Universe. 5/10, 2019. MPI Gravitational Physics and Complutense University of Madrid astrophysicists provide an historic, philosophical, cosmological and anthropic survey of this expansive frontier

Alonso-Serrano, Ana, et al, eds. The Multiverse. Universe. July, 2019. Co-editors A A-S, MPI Gravitational Physics, Mariusz Dabrowski, University of Szczecin, Poland, and Thomas Naumann, Deutsches Elektronen-Synchrotron, Germany introduce a special place for studies about a relatively infinite scenario, some 400 years after Galileo’s moon, which is filled with all manner of spatial and temporal cosmoses. Among the entries are Multiverse – Too Much or Not Enough? by Michael Heller, Possible Origins and Properties of an Expanding, Dark Energy Providing a Dark Multiverse by Eckhard Rebhan, and four McCullen Sandora Papers (search) about factoring habitability estimates for our home planet and cosmos within this vast milieu. While still another (Copernican) devaluation is alluded to, in our worldwide organic genesis, human/Earth beings can be returned to a central significance.

The idea of the Multiverse, as a collection of possible universes, has entered the area of physics and cosmology for good. The term 'Multiverse' was first suggested by the philosopher William James in 1895 (see Historic Prescience). The diversity of possible physical shapes of a universe within the multiverse can be interpreted in terms of diversity of possible ways to choose physical parameters and can be related to the issue of varying physical constants and varying physical laws. One approach is superstring theory which led to an idea of superstring landscape or many ways to choose the vacua after the symmetry breaking. Anyway, one can consider the studies related to the concept of the Multiverse as a new revolution or paradigm in cosmology. It can be understood as the next step in the Copernican transit, where our habitat has lost relevance gradually as unique or special. The notion of the multiverse emerges naturally from some developments in cosmology and particle physics. (Issue Proposal excerpt)

Ambjørn, Jan and Y. Watabiki.. Is the present acceleration of the Universe caused by merging with other universes? Journal of Cosmology and Astroparticle Physics. 12/11, December, 2023. In these years, Niels Bohr Institute, Copenhagen and Tokyo Institute of Technology (search JA) theorists are able to extend their mathematical conjectures to the farthest reaches of spacetime so to quantify, explain and wonder about these farthest multiversal realms.

"The main finding of our work is that the accelerated expansion of our universe, caused by the mysterious dark energy, might have a simple intuitive explanation, the merging with so-called baby universes, and that a model for this might fit the data better than the standard cosmological model," Jan Ambjørn, told LiveScience. The researchers' calculations showed that merging with other universes should increase the volume of our universe, which could b horizon.e perceived by our instruments as an expansion of the universe. (JA to LiveScience)

Barnes, Luke, et al. Galaxy Formation Efficiency and the Multiverse Explanation of the Cosmological Constant with EAGLE Simulations. arXiv:1801.08781. A nine member Australian, British, and Dutch group including Geraint Lewis and Jaime Salcido can now proceed to quantify, and contemplate entire cosmoses by way of certain variable physical properties. Might we then wonder how special could our collective Earthly witness on an infinitesimal orb actually be, as we forthwith begin to consider an infinity of potentially viable cosmoses?

Models of the very early universe, including inflationary models, are argued to produce varying universe domains with different values of fundamental constants and cosmic parameters. Using the cosmological hydrodynamical simulation code from the EAGLE collaboration, we investigate the effect of the cosmological constant on the formation of galaxies and stars. We simulate universes with values of the cosmological constant ranging from Λ=0 to Λ0×300, where Λ0 is the value of the cosmological constant in our Universe. We use our simulations to predict the observed value of the cosmological constant, given a measure of the multiverse. (Abstract excerpt)

We conclude that the impact of the cosmological constant on the formation of structure in the universe is not sufficient to explain the small observed value of Λ. The prediction depends crucially on the measure. If the observer creation rate had been sufficiently sharply peaked at values near Λ0, the measure would not much matter. But in fact, in the absence of a multiverse model that can convincingly justify a measure, it is not clear whether the anthropic prediction Λ is successful. Future work will consider varying more cosmological and fundamental parameters, to shed more light on which kind of universe is to be expected from a multiverse. (15-16)

Barreira, Alexandre, et al. Separate Universe Simulations with IllustrisTNG. arXiv:1904.02070. MPI Astrophysics and Kavli Institute for the Physics and Mathematics of the Universe, Tokyo theorists study “baryonic effects on power spectrum responses and higher-order statistics.” This German-American cosmic quantification project (see quote) uses ground and telescope instrumentation along with computational visualizations. See also an earlier Separate Universe Simulations entry (Monthly Notices of the Royal Astronomical Society (448/L11, 2015) for more context.

The IllustrisTNG (TNG + the next generation) project is a suite of state-of-the-art cosmological galaxy formation simulations. Each simulation evolves a large swath of a mock Universe from soon after the Big-Bang until the present day while taking into account a wide range of physical processes that drive galaxy formation. The simulations can be used to study a broad range of topics surrounding how the Universe — and the galaxies within it — evolved over time. These components of the visible matter are organized in a 'Cosmic Web' of sheets, filaments, and voids, inside which the basic units of cosmic structure - galaxies - are embedded. To test our current ideas on the formation and evolution of galaxies, we strive to create simulated galaxies as detailed and realistic as possible, and compare them to galaxies observed in the real universe.

Barrow, John. The Book of Universes: Exploring the Limits of the Cosmos. New York: Norton, 2011. For a long time before the current proof of myriad planets, it was assumed that our bioworld Earth bioworld not be the only one. Since the 1980s, the same logic has led to a proposal of multiple cosmoses, first theoretically and now experimentally. A Cambridge University mathematician and author (search) surveys an infinite spatial and temporal spacescape from its origins to current vicarious infinities. We are thus treated to fractal, Swiss cheese, spinning, undulating, chaotic, magnetic, random, probable, self-creating universes. Again how fantastic is it that we infinitesimal beings can yet imagine and gain such cosmic knowledge?

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