Related papers: Are Alien Civilizations Technologically Advanced?
The discovery of planets around massive stars is important for understanding how planet formation and evolution is conditioned by different stellar environments. However, current planetary search surveys have failed to detect planets around…
We are at a stage in our evolution where we do not yet know if we will ever communicate with intelligent beings that have evolved on other planets, yet we are intelligent and curious enough to wonder about this. We find ourselves wondering…
For centuries, humanity wondered if there were other worlds like ours in the Universe. For about a quarter of a century, we have known that planetary systems exist around other stars, and more than 3800 exoplanetary systems have been…
In this work, we explore constraints on the emergence and longevity of technologically intelligent civilizations in our Galaxy, considering the Fermi paradox. We argue that under optimistic assumptions about the probability of life and…
We propose a search for sources of directed energy systems such as those now becoming technologically feasible on Earth. Recent advances in our own abilities allow us to foresee our own capability that will radically change our ability to…
Given the fact that Earth is so far the only place in the Milky Way galaxy known to harbor life, the question arises of whether the solar system is in any way special. To address this question, I compare the solar system to the many…
It is shown that space travel, even in the most distant future, will remain confined to our own planetary system, and a similar conclusion will hold forth for any other civilization, no matter how advanced it might be, unless those…
We model the settlement of the galaxy by space-faring civilizations in order to address issues related to the Fermi Paradox. We explore the problem in a way that avoids assumptions about the intent and motivation of any exo-civilization…
What the future holds for the stellar populations of the Milky Way Galaxy may (optimistically) be predicted by study of their past histories, as written in the chemical abundance distributions, angular momentum distributions, velocity…
One of the primary open questions of astrobiology is whether there is extant or extinct life elsewhere the Solar System. Implicit in much of this work is that we are looking for microbial or, at best, unintelligent life, even though…
We investigated the habitability of the Milky Way, making use of recent observational analysis on the prevalence of Earth-sized planets, in order to estimate where and when potentially habitable star systems may have formed over the course…
The Fermi paradox is the discrepancy between the strong likelihood of alien intelligent life emerging (under a wide variety of assumptions) and the absence of any visible evidence for such emergence. We use this intriguing unlikeness to…
Extraterrestrial technology may exist in the Solar System without our knowledge. This is because the vastness of space, combined with our limited searches to date, implies that any remote unpiloted exploratory probes of extraterrestrial…
Despite great advances in our understanding of the formation of the Solar System, the evolution of the Earth, and the chemical basis for life, we are not much closer than the ancient Greeks to an answer of whether life has arisen and…
As of 2025, over 6000 planets are known to orbit stars other than our Sun. We can measure their sizes and orbital periods, infer their masses and temperatures, and constrain their compositions. Based on these data, about 1% of extrasolar…
It is shown that, contrary to an existing claim, the near equality between the lifetime of the sun and the timescale of biological evolution on earth does not necessarily imply that extraterrestrial civilizations are exceedingly rare.…
Motivated by recent progress in the study of early-type galaxies owing to technological advances, the launch of new space telescopes and large ground-based surveys, we attempt a short review of our current understanding of the recent…
The presence of dark energy in our universe is causing space to expand at an accelerating rate. As a result, over the next approximately 100 billion years, all stars residing beyond the Local Group will fall beyond the cosmic horizon and…
The lack of evidence for the existence of extraterrestrial life, even the simplest forms of animal life, makes it is difficult to decide whether the search for extraterrestrial intelligence (SETI) is more a high-risk, high-payoff endeavor…
The nearest stellar system consists of the stars Proxima, alpha Centauri A and B and at least one planet Proxima b. The habitability of Proxima b and any other planets are likely to be significantly influenced by the orbital evolution of…