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In the debate on the Fermi paradox, the predominant position is to take the absence of signs of extraterrestrial civilizations (ETCs) as an indication that there probably are no such civilizations. This position is usually justified with the following argument: If there were ETCs, we would expect one or more of them to have thoroughly colonized the galaxy by now; however, our solar system has not been colonized; therefore, ETCs probably do not exist. Two different motives are cited, in this context, as to why a civilization would relentlessly colonize the galaxy, namely the natural tendency to expand and the political need not to be outdone. The aim of the present paper is to call into question this argument and, hence, the position that it supports. I will argue that the cited motives do not constitute inexorable laws of behavior, but can be overridden by cultural factors. Furthermore, I will show that unbridled colonization tends to lead to resource scarcity and violent conflict. Therefore, a civilization has strong reasons to overcome the two motives and refrain from such colonization. My argument will not prove that it is impossible for an ETC to colonize the galaxy. But it will show that such behavior is so improbable that the absence of signs of it cannot be taken as evidence for the non-existence of ETCs. • The absence of signs of extraterrestrial civilizations does not indicate that there are no such civilizations. • A civilization has strong reasons to refrain from colonizing the whole galaxy. • The predominant position on the Fermi paradox fails to take into account cultural evolution. [ABSTRACT FROM AUTHOR]

The search for extraterrestrial intelligence is a fascinating and important endeavor, but it raises significant ethical and safety concerns. In the search for extraterrestrial intelligence, scientists use knowledge of physics to identify potential communication methods and signals that may be used by extraterrestrial civilizations. One of the most notable scientists to highlight these concerns was the late physicist Stephen Hawking, who cautioned that actively attempting to communicate with extraterrestrial civilizations could harm humanity. While it is true that we cannot predict the intentions of any potential extraterrestrial civilizations, some scientists argue that the potential advantages of seeking contact outweigh the potential risks. Deciding to initiate contact with extraterrestrial civilizations is a complex issue that requires balancing scientific curiosity with concerns for our own safety. The “Intelligence Trap” is a concept in psychology that suggests that highly intelligent people are more susceptible to cognitive biases and flawed thinking than less intelligent people. It can be argued that Hawking’s warnings may be an example of the so-called intelligence trap, as some evidence from the field of physics suggests. Nonetheless, Hawking emphasized that it is crucial for scientists and policymakers to carefully weigh the potential risks and benefits of such efforts and proceed with caution. [ABSTRACT FROM AUTHOR]

The search for extraterrestrial intelligence is a fascinating and important endeavor, but it raises significant ethical and safety concerns. In the search for extraterrestrial intelligence, scientists use knowledge of physics to identify potential communication methods and signals that may be used by extraterrestrial civilizations. One of the most notable scientists to highlight these concerns was the late physicist Stephen Hawking, who cautioned that actively attempting to communicate with extraterrestrial civilizations could harm humanity. While it is true that we cannot predict the intentions of any potential extraterrestrial civilizations, some scientists argue that the potential advantages of seeking contact outweigh the potential risks. Deciding to initiate contact with extraterrestrial civilizations is a complex issue that requires balancing scientific curiosity with concerns for our own safety. The “Intelligence Trap” is a concept in psychology that suggests that highly intelligent people are more susceptible to cognitive biases and flawed thinking than less intelligent people. It can be argued that Hawking’s warnings may be an example of the so-called intelligence trap, as some evidence from the field of physics suggests. Nonetheless, Hawking emphasized that it is crucial for scientists and policymakers to carefully weigh the potential risks and benefits of such efforts and proceed with caution.

In 1960, Jung lamented psychology's limited impact on global fate. Although Fordham tried to reassure him that Jungians were promoting his work, Jung was looking from the other end of the telescope, seeing the need to rescue humanity from its one‐sidedness that would ultimately lead to nuclear conflict. Astronomical evidence, such as the Fermi paradox, echoes Jung's concerns about likely self‐destruction. Rather than promoting Jungian ideas to interested groups, the imperative lies in identifying crucial messages for global survival and engaging the public in them. Science provides some useful lessons because its concerted efforts over centuries led to the gradual integration of scientific thinking into the public psyche. These lessons suggest that, to cross the border from the Jungian to wider public domain, compromises are necessary, such as simplifying messages and making engagement enchanting and practical. Analytical psychology's task goes beyond one individual, group, or even generation, and a debate is needed to begin to form a consensus on the way ahead. Some initial suggestions are made for adopting terminology the public can relate to, focusing on the transcendent function as the main vehicle to overcome one‐sidedness and conflict, and using figures like Nelson Mandela to demonstrate practical application. [ABSTRACT FROM AUTHOR]

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• Interstellar exploration is defined as bi-objective multi-vehicle problem with profits. • Mission return increases approximately linearly with mission duration. • Lower probe numbers enable more efficient routing through shorter transfers. In the past decade, the discovery of exoplanets has sparked new interests in the idea of interstellar travel and exploration. Despite various proposals for probe concepts and relevant technologies, there is a lack of extensive literature on viable exploration strategies for journeys beyond a single star system. Such exploration strategies might not only have implications on technology development strategies for achieving interstellar exploration but could also enrich existing models for galactic exploration feeding into solutions of the Fermi Paradox. This article presents optimal strategies for the exploration of a large number of near-by stars, using a dedicated, novel methodology, which sets it apart from existing literature: For the first time, the mission design problem of interstellar exploration is redefined as a bi-objective multi-vehicle open routing problem with profits. It is tackled by an adapted hybrid multi-objective genetic algorithm, which is further improved and modified according to the problem characteristics (e. g. large search space). The overall mission model assumes probes traveling on straight trajectories, utilizing flybys, and maintaining an average velocity of 10% of the speed of light. Surpassing prior research that typically relies on statistical models or restricted star data, the star models are founded on the second Gaia data release (Gaia DR2), which represents the most extensive star catalogue to the date of this study and is employed for the first time in the context of interstellar exploration. The resulting star model contains a maximum of 10,000 stars within a spherical region around Sol, covering a distance of 110 light years. It is found, that the number of explored stars J 1 scales with mission duration J 2 and probe number m according to J 1 ∼ J 2 m 0.66 , which provides an initial guidance for future interstellar mission design. Furthermore, the routes and selection of stars vary depending on the number of probes used: When conducting missions with a large number of probes, stars in close proximity to the Solar System are given more focus. On the other hand, missions with a small number of probes include more distant stars to facilitate shorter transfers along the route. Based on these findings, the following recommendations for interstellar exploration strategies can be drawn: When energy resources such as fuel reserves are scarce and the exploration mission is not limited to nearby stars, low probe numbers are more efficient. In contrast, high probe numbers enable faster exploration of nearby stars but involve less resource-efficient transfers, making them a suitable option for small, remotely propelled probe concepts. To address crowding effects in high probe number missions, swarm-based probe concepts are recommended based on the scaling law characteristics derived. [ABSTRACT FROM AUTHOR]

This paper provides a Christian philosophical and theological response to the moral imperative of human advancement through multiplanetarism as emerging from the Great Filter theory. First, it explains the Fermi paradox that underlies the Great Filter theory. Next, it explores this theory itself and its motivational power in driving advancement toward multiplanetarism. In particular, we explore two motives behind the multiplanetary efforts that are (in part) guided by the Great Filter theory, analyzing the relevant statements of SpaceX founder and chief engineer Elon Musk. Finally, we assess these motivations (and the accompanying normative assumptions) behind space exploration and multiplanetarism from the perspective of Reformational philosophy, using Herman Dooyeweerd's theory of ground motives as a lens. Thus, the paper's leading research question is this: How can we assess the current attempts at securing a multiplanetary existence for humankind in the light of Dooyeweerd's theory of ground motives? [ABSTRACT FROM AUTHOR]

In his review essay on World Statehood, Morgan poses three questions, namely: does my conceptualization imply conflation of agency and structure; is the realist processual account of time contradictory; and have we humans already reached the limit of the possible? I address each question briefly one at a time, arguing that the concept of self-transformative capacity of contexts does not imply conflation; that various processes with different durations can exhibit patterns that can be reasonably discussed and assessed and, with caution, also used in anticipations; and that there is no cosmic law or limit that inevitably hinders humanity's further progress. [ABSTRACT FROM AUTHOR]

Within the uncertainties of involved astronomical and biological parameters, the Drake Equation typically predicts that there should be many exoplanets in our galaxy hosting active, communicative civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing the importance of planetary tectonic style for biological evolution. We summarize growing evidence that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated emergence and evolution of complex species. We further suggest that both continents and oceans are required for ACCs because early evolution of simple life must happen in water but late evolution of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox (1) by adding two additional terms to the Drake Equation: foc (the fraction of habitable exoplanets with significant continents and oceans) and fpt (the fraction of habitable exoplanets with significant continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by demonstrating that the product of foc and fpt is very small (< 0.00003–0.002). We propose that the lack of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on exoplanets with primitive life. [ABSTRACT FROM AUTHOR]

The given text explores the concept of architectural replication and its relationship to time, space, and the environment. It references various sources and authors to discuss ideas such as the future perfect mode and the industrial cosmogenesis of the Earth. The text also mentions the potential risks and consequences of large-scale projects, such as geo-engineering for climate change mitigation. It provides a range of perspectives and ideas for further exploration in the field of architecture. [Extracted from the article]

The Fermi paradox and the Drake equation seem to be incompatible. Here we shall show that is not so, and the paradox actually justifies the assumptions made in formulating this equation. • We use the Fermi paradox to set up a problem in the calculus of variations. • We solve the associated Euler-Lagrange equation and obtain a formula for the growth of communicating societies. • We show how this work justifies the assumptions Drake made in formulating his famous equation. [ABSTRACT FROM AUTHOR]

The search for extraterrestrial intelligence is a fascinating and important endeavor, but it raises significant ethical and safety concerns. In the search for extraterrestrial intelligence, scientists use knowledge of physics to identify potential communication methods and signals that may be used by extraterrestrial civilizations. One of the most notable scientists to highlight these concerns was the late physicist Stephen Hawking, who cautioned that actively attempting to communicate with extraterrestrial civilizations could harm humanity. While it is true that we cannot predict the intentions of any potential extraterrestrial civilizations, some scientists argue that the potential advantages of seeking contact outweigh the potential risks. Deciding to initiate contact with extraterrestrial civilizations is a complex issue that requires balancing scientific curiosity with concerns for our own safety. The "Intelligence Trap" is a concept in psychology that suggests that highly intelligent people are more susceptible to cognitive biases and flawed thinking than less intelligent people. It can be argued that Hawking's warnings may be an example of the so-called intelligence trap, as some evidence from the field of physics suggests. Nonetheless, Hawking emphasized that it is crucial for scientists and policymakers to carefully weigh the potential risks and benefits of such efforts and proceed with caution., Competing Interests: SMJ. Mortazavi and JS. Welsh, as the Editorial Board Members, were not involved in the peer-review and decision-making processes for this manuscript., (Copyright: © Journal of Biomedical Physics and Engineering.)

Lem’s The Perfect Vacuum is a collection of reviews by fictional authors of non-existent scientific papers. This includes a lecture by Alfred Testa delivered on the occasion of the Nobel Prize in Physics. It is actually a recapitulation of a cosmological concept based on the discovery of a forgotten idea of Aristides Acheropoulos to explain the silentium universi. Why is the universe silent? Why does no one answer our calls sent to the interstellar distances? Why is our search for extraterrestrial civilizations unsuccessful? In his lecture, Testa layers before the audience the fundamental questions of the relationship between mathematics and physics, an interpretation of the latest discoveries of modern cosmology, and an explanation of the physical laws of relativity theory and quantum mechanics, including the metaphysical question of why they are just that. Because Lem sets before the reader a story of scientific discovery, the opportunity is offered to take it quite seriously, not as fiction but as science, and to look at its various components through the eyes of contemporary science.

Considering the vastness of time and space, if one civilization — ours — has been able to advance technologically to the point of leaving its own planet, why technosignatures from other advanced extraterrestrial civilizations have never been identified? In this paper, I offer an explanation for that, developing an insight originally presented by Webb and others and using insights from astrobiology, sustainability and archaeology. I argue that there exists a universal limit to technological development (ULTD), determined by decreasing technological returns on societal complexity, increasing maintenance costs of existing technology, the eventual untestability of scientific theories due to the high costs involved and the unattainable energy levels needed to test them and civilization-damaging catastrophes. I also argue, based on the principle of mediocrity, that the ULTD is not much above our current level of technological development. Technology, therefore, will not be able to provide another home to humankind. Such a possibility should be taken into consideration during the decision-making process concerning both the allocation of resources to research or mitigation of technology-induced planetary changes and the definition of goals to space exploration. • The Fermi Paradox may be solved by the existence of a Universal Limit for Technological Development (ULTD). • The ULTD prevents extraterrestrial civilizations of reaching a technological level that allows for space colonization. • The principle of mediocrity suggests that we may be close to the ULTD. • SETI programs function as a "cosmic bottle-messaging": no sustained intercivilizational communication will ever happen. [ABSTRACT FROM AUTHOR]

This paper aims to justify the concept of natural intelligence in the biosemiotic context. I will argue that the process of life is (i) a cognitive/semiotic process and (ii) that organisms, from bacteria to animals, are cognitive or semiotic agents. To justify these arguments, the neural-type intelligence represented by the form of reasoning known as anthropic reasoning will be compared and contrasted with types of intelligence explicated by four disciplines of biology – relational biology, evolutionary epistemology, biosemiotics and the systems view of life – not biased towards neural intelligence. The comparison will be achieved by asking questions related to the process of observation and the notion of true observers. To answer the questions I will rely on a range of established concepts including SETI (search for extraterrestrial intelligence), Fermi's paradox, bacterial cognition, versions of the panspermia theory, as well as some newly introduced concepts including biocivilisations, cognitive/semiotic universes, and the cognitive/semiotic multiverse. The key point emerging from the answers is that the process of cognition/semiosis – the essence of natural intelligence – is a biological universal. [ABSTRACT FROM AUTHOR]

The Search for Extraterrestrial Intelligence (SETI) project has been scanning the heavens for signs of intelligent life for almost half a century. So far, nothing. This raises the question physicist Enrico Fermi asked, "Where is everybody?" The probability of intelligent life on another planet is high so why the silence? Technological civilizations may be short-lived. The mechanisms of evolution that lead to intelligent life and technological development also lead to propensities traditionally labeled as sin. These propensities make it difficult for technological civilizations to survive long enough to escape their home planet. [ABSTRACT FROM AUTHOR]

In their article, 'That is not dead which can eternal lie: the aestivation hypothesis for resolving Fermi's paradox', Sandberg et al. try to explain the Fermi paradox (we see no aliens) by claiming that Landauer's principle implies that a civilization can in principle perform far more ( ∼ 10 30 times more) irreversible logical operations (e.g., error-correcting bit erasures) if it conserves its resources until the distant future when the cosmic background temperature is very low. So perhaps aliens are out there, but quietly waiting. Sandberg et al. implicitly assume, however, that computer-generated entropy can only be disposed of by transferring it to the cosmological background. In fact, while this assumption may apply in the distant future, our universe today contains vast reservoirs and other physical systems in non-maximal entropy states, and computer-generated entropy can be transferred to them at the adiabatic conversion rate of one bit of negentropy to erase one bit of error. This can be done at any time, and is not improved by waiting for a low cosmic background temperature. Thus aliens need not wait to be active. As Sandberg et al. do not provide a concrete model of the effect they assert, we construct one and show where their informal argument goes wrong. [ABSTRACT FROM AUTHOR]

Highlights • Planetary distances and a definition of life thwart resolution of the Fermi paradox. • Electromagnetic radiation is the best medium for probing exoplanets for signs of life. • Mid-IR spectroscopy is the most informative region of the electromagnetic spectrum. • Moon-based mid-IR spectra yield more information about life than any other platform. • Current estimates for a lunar platform are 10-fold lower than previous estimates. Abstract The failure to resolve the 70 year old Fermi paradox has been limited by the vastness of the Universe, the inability to search even a fraction of the Universe in a reasonable time period, and the lack of agreement on the criteria for life. We suggest that one approach is to use cyclical perturbations of thermodynamic equilibria on exoplanets within range of the most powerful mid-infrared (mid-IR) telescopes as a general screening tool for the possible existence of any form of life. We argue that the optimal platform for such a mid-IR search is on the Earth's moon. [ABSTRACT FROM AUTHOR]

Highlights • We update calculations of population- and energy-related "doomsdays" from Von Hoerner (1975). • Current trends show "doomsdays" related to a population singularity or agricultural limitations may not occur. • "Doomsdays" may occur due to greenhouse gas emissions by 2300, and/or direct heating by 2300–2400. • Using ∼1016–1017 W may raise Earth's temperature by 12 K or require complete coverage by solar collectors by ∼2400 • If this also applies to extraterrestrial civilizations, it may support the "sustainability solution" to the Fermi Paradox. Abstract Von Hoerner ("Population Explosion and Interstellar Expansion," Journal of the British Interplanetary Society, 28, 691–712, 1975; hereafter VH75) examined the effects of human population growth and predicted agricultural, environmental, and other problems from observed growth rate trends. Using straightforward calculations, VH75 predicted the "doomsday" years for these scenarios (≈2020–2050), when we as a species should run out of space or food, or induce catastrophic anthropogenic climate change through thermodynamically unavoidable direct heating of the planet. Now that over four decades have passed, in this paper we update VH75. We perform similar calculations as that work, with improved data and trends in population growth, food production, energy use, and climate change. For many of the impacts noted in VH75 our work amounts to pushing the "doomsday" horizon back to the 2300 s–2400 s (or much further for population-driven interstellar colonization). This is largely attributable to using worldwide data that exhibit smaller growth rates of population and energy use in the last few decades. While population-related catastrophes appear less likely than in VH75, our continued growth in energy use provides insight into possible future issues. We find that, if historic trends continue, direct heating of the Earth will be a substantial contributor to climate change by ≈2260, regardless of the energy source used, coincident with our transition to a Kardashev type-I civilization. We also determine that either an increase of Earth's global mean temperature of ≈12 K will occur or an unreasonably high fraction of the planet will need to be covered by solar collectors by ∼2400 to keep pace with our growth in energy use. We further discuss the implications in terms of interstellar expansion, the transition to type II and III civilizations, SETI, and the Fermi Paradox. We conclude that the "sustainability solution" to the Fermi Paradox is a compelling possibility. [ABSTRACT FROM AUTHOR]

Abstract A methodological problem is inherent in any discussion of extraterrestrial engineering and its detectability: how to distinguish detection signatures of such astroengineering from "natural", non-intentional, albeit exotic, processes? In practice, searches for traces and manifestations of advanced technological civilizations have been reduced so far to searching for outliers in the allegedly well-known regularities expected from natural astrophysical sources. This procedure, however, is an epistemological minefield, for at least two reasons: (i) prior datasets on which the regularities are based might be contaminated by artefacts, and (ii) the procedure of computation of unobservable quantities usually contains the implicit assumption of the non-intentional nature of sources. In other words, we are facing a Catch-22-type problem: in order to prove the artificial nature of a source, we seemingly need to first assume that it is not artificial. In contrast to most problems in science, this one could possibly be aggravated, rather than reduced, with the progress of our scientific understanding. Some possible recourses, as well as directions for further work toward building a comprehensive methodology of the Dysonian SETI, are discussed. Highlights • We consider epistemological and methodological aspect of the search for extraterrestrial artefacts (SETA). • SETA projects are impacted by important methodological problems and biases which have not been studied in the literature so far. • Our analysis offers some guidelines for the selection of objects of interest from a sample of astrophysical sources. • The importance of establishing the proper context for SETA and of utilizing the experience of terrestrial archaeology. [ABSTRACT FROM AUTHOR]

The fear of annihilation by an advanced civilization may not be limited to Earth, and it may help explain the silence of the cosmos. [ABSTRACT FROM AUTHOR]

The article offers information about exoplanets and the continuing search and exploration for extraterrestrial life in the outer space. It features physicist Enrico Fermi and his thoughts about aliens and signs depicting the existence of other intelligent civilizations in the Milky Way galaxy. Other information related to the emergence and evolution of extrasolar life is presented.

How should the Fermi paradox affect an estimate of humankind’s likelihood and best means of long-term survival? A significant probability that many other civilizations have been in our situation but failed to become spacefaring increases the probability that our optimal existential risk strategies are costly, likely to fail, likely to leave traces if they do fail, and might require talents that mankind has but that other scientifically advanced species lack. The Fermi paradox implies that we should seek scientific data based on astronomical observations not accessible to civilizations that lived in the distant past, and that we should create machines to flood our galaxy with radio signals conditional on our civilization’s collapse. Our ability to use Bayesian updating on the Fermi paradox reduces the chance that aliens exist but are hiding from us because of their desire to not interfere in our development: giving us a false understanding of the fate of intelligent life in the universe would cloud our understanding of existential risks. The paradox also provides clues as to types of trap that might destroy us. The possibility that our universe is fine-tuned not only for life but also for the Fermi paradox magnifies these results. [ABSTRACT FROM AUTHOR]

In a recent article in this journal, Lingam and Loeb developed an excellent heuristic for searches for biosignatures versus technosignatures. We consider two ways in which their approach could be extended and sharpened, with focus on durability of technosignatures. We also note an important consequence of the adopted heuristic that offers strong support to the ideas of the Dysonian Search for ExtraTerrestrial Intelligence (SETI). [ABSTRACT FROM AUTHOR]

Highlights • The Fermi paradox may be telling us that the value of a certain integral is minimal. • We identify this integral and obtain the relevant Euler-Lagrange equation. • The equation is solved to yield an expression for the number of communicating societies. Abstract One of the few pieces of hard data that we have in connection with SETI is embodied in Fermi's famous question, often stated simply as: Where is everyone? Our purpose here is to show that this "paradox" is telling us something about the number of communicating societies in the galaxy and the rate at which such societies "grow". Our analysis is based on a mathematical technique that is of fundamental importance in a number of areas of physics. [ABSTRACT FROM AUTHOR]

Whether we are alone in the universe is one of the greatest mysteries facing humankind. Given the >100 billion stars in our galaxy, many have argued that it is statistically unlikely that life, including intelligent life, has not emerged anywhere else. The lack of any sign of extraterrestrial intelligence, even though on a cosmic timescale extraterrestrial civilizations would have enough time to cross the galaxy, is known as Fermi's Paradox. One possible explanation for Fermi's Paradox is the Zoo Hypothesis which states that one or more extraterrestrial civilizations know of our existence and can reach us, but have chosen not to disturb us or even make their existence known to us. I propose here a proactive test of the Zoo Hypothesis. Specifically, I propose to send a message using television and radio channels to any extraterrestrial civilization(s) that might be listening and inviting them to respond. Even though I accept this is unlikely to be successful in the sense of resulting in a response from extraterrestrial intelligences, the possibility that extraterrestrial civilizations are monitoring us cannot be dismissed and my proposal is consistent with current scientific knowledge. Besides, issuing an invitation is technically feasible, cheap and safe, and few would deny the profound importance of establishing contact with one or more extraterrestrial intelligences. A website has been set up ( http://active-seti.info ) to encourage discussion of this proposal and for drafting the invitation message. [ABSTRACT FROM AUTHOR]

The article offers the author's insights on arguments to the Fermi's paradox (FP). Topics include the search for extraterrestrial intelligence (SETI), opposition to the theory of evolution through natural selection, and the Copernican revolution principle by mathematician and astronomer Nicolaus Copernicus.

In this paper, percolation theory is employed to place tentative bounds on the probability p of interstellar travel and the emergence of a civilization (or panspermia) that colonizes the entire Galaxy. The ensuing ramifications with regard to the Fermi paradox are also explored. In particular, it is suggested that the correlation function of inhabited exoplanets can be used to observationally constrain p in the near future. It is shown, by using a mathematical evolution model known as the Yule process, that the probability distribution for civilizations with a given number of colonized worlds is likely to exhibit a power-law tail. Some of the dynamical aspects of this issue, including the question of timescales and generalizing percolation theory, were also studied. The limitations of these models, and other avenues for future inquiry, are also outlined. Key Words: Complex life-- Extraterrestrial life--Panspermia--Life detection--SETI. Astrobiology 16, 418-426. [ABSTRACT FROM AUTHOR]

The so-called Fermi paradox claims that if technological life existed anywhere else, we would see evidence of its visits to Earth-and since we do not, such life does not exist, or some special explanation is needed. Enrico Fermi, however, never published anything on this topic. On the one occasion he is known to have mentioned it, he asked 'Where is everybody?'-apparently suggesting that we do not see extraterrestrials on Earth because interstellar travel may not be feasible, but not suggesting that intelligent extraterrestrial life does not exist or suggesting its absence is paradoxical. The claim 'they are not here; therefore they do not exist' was first published by Michael Hart, claiming that interstellar travel and colonization of the Galaxy would be inevitable if intelligent extraterrestrial life existed, and taking its absence here as proof that it does not exist anywhere. The Fermi paradox appears to originate in Hart's argument, not Fermi's question. Clarifying the origin of these ideas is important, because the Fermi paradox is seen by some as an authoritative objection to searching for evidence of extraterrestrial intelligence-cited in the U.S. Congress as a reason for killing NASA's SETI program on one occasion. But evidence indicates that it misrepresents Fermi's views, misappropriates his authority, deprives the actual authors of credit, and is not a valid paradox. Key Words: Astrobiology-SETI-Fermi paradox-Extraterrestrial life. Astrobiology 15, 195-199. [ABSTRACT FROM AUTHOR]

This commentary summarizes insights and discussions about the status of women leaders in STEM (science, technology, engineering, and medicine). While many academic institutions now train close to 50 % female students in STEM disciplines, there is a major underrepresentation of qualified women in leadership roles. Women are admitted to the basements of STEM institutions, but only few make it to the top floor. We see male superstars receiving well-deserved recognitions and advancements. Unfortunately, their female counterparts are often held back or cut down by both male and female colleagues. Increasing reports of acts of discrimination reported by women in STEM fields are a symptom. Unilateral hierarchy is the root cause. Just increasing the quote/proportion of women and underrepresented minorities at an institution is therefore not enough to address the underlying problem. At Stanford Radiology, we started a major initiative to increase the representation of qualified women and other underrepresented minorities in our leadership teams in order to ensure that every member of the Department has an advocate at the leadership table, when decisions are being made. Diverse leadership teams are vital to creating a culture of respect and inclusion for everyone. [ABSTRACT FROM AUTHOR]

Abstract: Many hypotheses have been raised to explain the famous Fermi paradox. One of them is that self-replicating probes could have explored the whole Galaxy, including our Solar System, and that they are still to be detected. In this scenario, it is proposed here that probes from neighboring stellar systems could use the stars they orbit as gravitational lenses to communicate efficiently with each other. Under this hypothesis, a novel SETI approach would be to monitor the solar focal regions of the most nearby stars to search for communication devices. The envisioned devices are probably not detectable by imagery or stellar occultation, but an intensive multi-spectral monitoring campaign could possibly detect some communication leakages. Another and more direct option would be to message the focal regions of nearby stars in an attempt to initiate a reaction. [Copyright &y& Elsevier]