Related papers: Introduction: Detectability of Future Earth
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…
The data recently accumulated by the Kepler mission have demonstrated that small planets are quite common and that a significant fraction of all stars may have an Earth-like planet within their Habitable Zone. These results are combined…
The search for extrasolar Earth-like planets is underway. Over 100 extrasolar giant planets are known to orbit nearby sun-like stars, including several in multiple-planet systems. These planetary systems are stepping stones for the search…
Upcoming biosignature searches focus on indirect indicators to infer the presence of life on other worlds. Aside from just signaling the presence of life, however, some biosignatures can contain information about the state that a planet's…
In a recent study (Garrett, 2011), I described theoretical arguments and empirical evidence showing how civilization evolution might be considered from a purely physical basis. One implication is that civilization exhibits the property of…
It is well-known that the chances of success of SETI depend on the longevity of technological civilizations or, more broadly, on the duration of the signs of their existence, or technosignatures. Here, we re-examine this general tenet in…
We utilize anthropic reasoning to demonstrate that we are typical observers of our reference class under a self-sampling assumption by investigating the definition of what a civilization is. With reference to the conflict between such…
Diffraction fundamentally limits our ability to image and characterize exoplanets. Current and planned coronagraphic searches for exoplanets are making incredible strides but are fundamentally limited by the inner working angle of a few…
Can information theory provide insights into whether exoplanets are habitable? Here we apply information theory to a range of simulated exoplanet transmission spectra as a diagnostic tool to search for potential signatures of life on…
In this article an analysis of the fundamentals used to search for extraterrestrial artificial signals in the galaxy, which have been developing for more than five decades, is presented. It is shown that the key factor for the success of…
The search for exoplanetary life must encompass the complex geological processes reflected in an exoplanet's atmosphere, or we risk reporting false positive and false negative detections. To do this, we must nurture the nascent discipline…
No present observations suggest a technologically advanced extraterrestrial intelligence (ETI) has spread through the galaxy. However, under commonplace assumptions about galactic civilization formation and expansion, this absence of…
The impact of exoplanet science on both the scientific community and on the general public is presented through various indicators and examples. It is estimated that about 3-4% of all refereed astronomy articles focus on exoplanets, and…
This paper outlines astrophysical issues related to the long term fate of the universe. We consider the evolution of planets, stars, stellar populations, galaxies, and the universe itself over time scales which greatly exceed the current…
For about the last 60 years the search for extraterrestrial intelligence has been monitoring the sky for evidence of remotely detectable technological life beyond Earth, with no positive results to date. While the lack of detection can be…
The last 25 years have been revolutionary in astronomy, as the field of exoplanets has gone from no known planets outside the Solar System to thousands discovered over the last year few years. This represents a rapid increase not just in…
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.…
With the discovery of hundreds of exoplanets and a potentially huge number of Earth-like planets waiting to be discovered, the conditions for their habitability have become a focal point in exoplanetary research. The classical picture of…
The search for habitable planets like Earth around other stars fulfils an ancient imperative to understand our origins and place in the cosmos. The past decade has seen the discovery of hundreds of planets, but nearly all are gas giants…
In the coming years, it is likely that the first potentially Earth-like planets will be discovered orbiting other stars. Once found, the characterisation of those planets will play a vital role in determining which will be chosen as the…