Alien Worlds Galore

Cruz, María; Coontz, Robert

doi:10.1126/science.340.6132.565

Cited by 4 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Twenty years ago, in 1995, the first extrasolar planet orbiting a main sequence solar-type star, 51 Pegasi, was detected (Mayor and Queloz, 1995). Nowadays, several thousand of exoplanets and exoplanet candidates are announced, dozens of them being located in the so called habitable zone: a zone where exoplanets permitted to have liquid water on their solid surface (Cruz and Coontz, 2013;Kopparapu et al, 2013). This large amount of discovered exoplanets allowed to achieve an unprecedented advancement on our understanding of formation and evolution of exoplanets, although, sometimes, newly discovered planets bring more questions than answers.…”

Section: Introductionmentioning

confidence: 99%

Which Type of Planets do We Expect to Observe in the Habitable Zone?

Adibekyan

Figueira

Santos

2016

Orig Life Evol Biosph

View full text Add to dashboard Cite

We used a sample of super-Earth-like planets detected by the Doppler spectroscopy and transit techniques to explore the dependence of orbital parameters of the planets on the metallicity of their host stars. We confirm the previous results (although still based on small samples of planets) that super-Earths orbiting around metal-rich stars are not observed to be as distant from their host stars as we observe their metal-poor counterparts to be. The orbits of these super-Earths with metal-rich hosts usually do not reach into the Habitable Zone (HZ), keeping them very hot and inhabitable. We found that most of the known planets in the HZ are orbiting their GK-type hosts which are metal-poor. The metal-poor nature of planets in the HZ suggests a high Mg abundance relative to Si and high Si abundance relative to Fe. These results lead us to speculate that HZ planets might be more frequent in the ancient Galaxy and had compositions different from that of our Earth.

show abstract

Section: Introductionmentioning

confidence: 99%

Which Type of Planets do We Expect to Observe in the Habitable Zone?

Adibekyan

Figueira

Santos

2016

Orig Life Evol Biosph

View full text Add to dashboard Cite

show abstract

“…In November 2001 came the first observation of an exoplanet atmosphere (HD 209458 b). As of 2013 Cruz and Coontz [9] estimated that our Galaxy (and there are 100 to 200 billion galaxies in our Universe) contains at least as many planets as stars and there are 200 to 500 billion stars per galaxy! In addition, according to Brandeker [10] there is "… at least one planet for every solartype star."…”

Section: Exoplanetsmentioning

confidence: 99%

“…Based upon the Kepler Satellite Observatory data there are approximately as many exoplanets as stars (Cruz, [9] and Brandeker, [10]). That does not mean that there is an exoplanet around every star , but rather that, for example, for every 8 stars there may be one star with 8 planets around it, like our Sun, or two of these stars with 4 exoplanets around each or one with 5orbiting exoplanets and one with 3, etc.…”

Section: How Soon Will We Discover Alien Life?mentioning

confidence: 99%

“…In thenumerical example S = Table 1. The length of time in years between a civilizations' emergence of cyborgs and/or interstellar communication capability and their demise, C to D or d. 100,000 100,000 400,000 4,000,000 40,000,000 400,000,000 4 ×10 9 1,000,000 1,000,000 4,000,000 40,000,000 400,000,000 4,000,000,000 4 ×10 10…”

Section: How Soon Will We Discover Alien Life?mentioning

confidence: 99%

See 1 more Smart Citation

Application of High-Frequency Gravitational Waves to the Cataclysmic Event of Our First Encounter with Intelligent Extraterrestrial Beings

Baker¹,

Baker²

2016

JAMP

View full text Add to dashboard Cite

Three advances are proposed as a pathway to the cataclysmic event of our first encounter with intelligent extraterrestrial beings. First, discovery of very large numbers of extraterrestrial planets, "exoplanets" (possibly as many as10 23 in our Universe); second, introduction of electronic components into the human body evolving into a cybernetic and biological "cyborg," a model for an extraterrestrial being Cyborgs might allow advanced civilizations to endure hundreds of thousands of years. Third, the recent development of high-frequency gravitational wave (HFGW) detectors, the communication means of choice for an advanced cyborg civilization since they are not easily absorbed like electromagnetic radiation. Six HFGW detectors are presented for application to our first encounter with intelligent extraterrestrial beings. Numerical estimates are made for the failure of extraterrestrial civilizations such that no two exist at the same time (Fermi's Paradox). It is concluded that there might remain at least ≈1.48 × 10 8 Worlds intercommunicating with HFGWs at any one time in any one region of our Universe. The predicted form of extraterrestrial beings is by means of animaginary, but based upon comprehensively documented and detailed projection of the evolution of "Earthling" homosapiens, to become "cyborgs." It is proposed that such long-living cyborg forms of intelligent beings would be encountered by us. The first cataclysmic encounter with them is expected to be interception of their interstellar communications. The predicted frequency of intercepted messages under one set of assumptions is at least 1500 per day. After decoding the intercepted messages, keys may be found to improve vastly the present and future quality of life for us earthlings. Advanced beings might utilize direct brain-to-brain communication and it is concluded that research into brain-to-brain communication and HFGW detection are encouraged.

show abstract

Is Everyone Probably Elsewhere?

2023

View full text Add to dashboard Cite

It has been widely discussed whether the existence of other universes than the known universe is a purely metaphysical consideration. This paper argues to the contrary that the existence of other universes is a meaningful hypothesis, which can be tested based on observable data. The paper applies the perspective of observer bias as an approach for assigning probabilities to the mutually excluding hypotheses of universe vs. multiverse, i.e., whether the known universe is the only universe, or just one universe in an ensemble of universes, a so-called multiverse. The basic idea of the paper relies on the following consideration. In a multiverse, the vast majority of observers would live in universes that are more life friendly. Thus, conditional on there being a multiverse, we should expect to find ourselves in a universe with values of the fundamental parameters that provide particularly fertile grounds for life. In contrast, if there is only a single universe, it may well be the case that there is still a few observers even if the parameters are far from ideal for life, and in that case, those observers will find values of the parameters that are not ideal for intelligent life. It may well be the case that, among all parameter configurations that allow life at least somewhere, those that are not ideal for life far outnumber those that are ideal for life. Based on this elementary consideration, the paper proceeds to propose a quantitative framework to determine probabilities for either hypothesis. In particular, it is described how a future ab initio determination of some of the factors in the Drake equation may be used to infer which one of the two hypotheses is the more likely. A quantitative approach to this end is proposed. Expressing these factors of the Drake equation in the context of the two hypotheses, a general likelihood approach is first described. Then, to support intuition, example computations are provided, illustrating how an actual hypothesis test would work in practice.

show abstract

Alien Worlds Galore

Cited by 4 publications

References 0 publications

Which Type of Planets do We Expect to Observe in the Habitable Zone?

Which Type of Planets do We Expect to Observe in the Habitable Zone?

Application of High-Frequency Gravitational Waves to the Cataclysmic Event of Our First Encounter with Intelligent Extraterrestrial Beings

Is Everyone Probably Elsewhere?

Contact Info

Product

Resources

About