Astrophysical and Cosmological Constraints on Life

Mason, Paul; Biermann, Peter L.

doi:10.1016/b978-0-12-811940-2.00005-8

Cited by 9 publications

(22 citation statements)

References 159 publications

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“…The cosmic web ultimately stretches out to small clusters like the Local Group and out to the lower density regions of the cosmos. Figure 1 also illustrates the large scale distribution of life in the universe [2]. The universe is a violent and dangerous place.…”

Section: The Emergence Of Structurementioning

confidence: 99%

“…The universe is a violent and dangerous place. Mason and Biermann [2] suggest that the densest regions of galaxy clusters remain uninhabited by complex life as the result of extreme conditions from AGN activity, galaxy mergers, as well as high star formation, gamma-ray burst, and supernova rates. Low density regions containing low metallicity dwarf galaxies are also likely uninhabited.…”

Section: The Emergence Of Structurementioning

confidence: 99%

“…Low density regions containing low metallicity dwarf galaxies are also likely uninhabited. This concept is generalized as the Super-Galactic Habitable Zone [2].…”

Section: The Emergence Of Structurementioning

confidence: 99%

“…Planets within the disks of spiral galaxies have less exposure to environmental hazards; especially intense particle fluxes and (low metallicity) gamma-ray bursts. Mason and Biermann [2] suggest that the Galactic magnetic disk wind produced by the steady occurrence of supernovae in the disk provides a magnetic protection akin to the heliosphere of the Sun. Galactic cosmic-rays are accelerated by local magnetic fields within supernova remnants [3,4], like the Crab Nebula shown in Figure 3.…”

Section: A Central Role For Supernovaementioning

confidence: 99%

“…The universe becomes habitable for life in stages. Simple life became possible roughly 9 billion years ago and complex life emerged about 5 billion years ago and then only within the moderate density, Super-Galactic Habitable Zone[2]. Credit:Mason and Biermann (2017) …”

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confidence: 99%

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From Big-Bang to Big Brains

Mason¹

2019

Proceedings of Frontier Research in Astrophysics – III — PoS(FRAPWS2018)

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I suggest that many deep connections between astrophysical processes and the emergence and evolution of life in the universe are beginning to be revealed. The universe has changed dramatically over its history and so too have the conditions for life. The multi-frequency nature of cosmic sources has had and continues to have significant effects on the habitability of planetary surfaces. The first potentially habitable exoplanets will be characterized soon and these observations will shed light on the prospects for the discovery of extrasolar life. Most stars likely do not host complex life. Single-celled creatures might be inevitable on some planets under a wide range of conditions. However, multicellular life may not develop at all in many cases, due to extreme environments or catastrophe. Complex life probably requires hospitable conditions lasting billions of years, like we have enjoyed here on Earth. The story of life on Earth is one of intense biosphere production that, for example, changed the chemical composition of the atmosphere and the oceans. Niches for oxygen-consuming life opened the way for animals. This may not be an easily crossed threshold. Evolution of life on Earth was punctuated by at least 5 major mass extinctions and many minor ones. The stresses placed on life by the geological and extraterrestrial environment and natural selection have honed members of the surviving species into beings well adapted to their environments. However, high intelligence is not at all an inevitable outcome of this process. 'Big brains', those capable of establishing a technological civilization, did not develop in the oceans of Earth, despite billions of years. Even then, big brains do not necessarily translate into ultimate success. Habitable conditions on every planet will eventually end. For life originating on a planet to succeed, intelligence and a technological civilization is needed to protect the planet's habitability. After 4.5 billion years, only now is life on Earth capable of developing protection against mass extinction by, for example, asteroid impact avoidance and contagious illness prevention. Without the development of science, any planetary civilization is doomed to tread water until the next mass extinction. While we may not expect to be communicating with extraterrestrials any time soon or even to find a planet with complex life, I am optimistic that soon the large subset of uninhabitable planets will begin to become characterized. In these brief comments, I summarize some connections between topics of modern astrophysics and life, especially so-called life as we know it. All of my attempts to characterize life as we don't know it have fallen flat.

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Section: The Emergence Of Structurementioning

confidence: 99%

Section: The Emergence Of Structurementioning

confidence: 99%

“…Low density regions containing low metallicity dwarf galaxies are also likely uninhabited. This concept is generalized as the Super-Galactic Habitable Zone [2].…”

Section: The Emergence Of Structurementioning

confidence: 99%