Popular Physics
Boats float supported only by buoyancy at rest and at very low speeds. As the speed increases, a hull capable of planing makes a sharp transition to a lifting surface while plowing up the bow wave. As the speed increases further the boat…
Von Hoerner (1975) 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…
The METI risk problem refers to the uncertain outcome of sending transmissions into space with the intention of messaging to extraterrestrial intelligence (METI). Here, I demonstrate that this uncertainty is undecidable by proving that that…
An essential component of the long-term success of scientific research is communicating the methodology and significance of new results to the wider public. Utilising various social media platforms is a vital tool for this endeavour. Over…
The Search for Extraterrestrial Intelligence (SETI) makes certain assumptions which guide all current search programs. To illustrate some, this includes (1) that interstellar flight is not possible (2) that the motivations of interstellar…
In the first papers of our series on interstellar generation ships we have demonstrated that the numerical code HERITAGE is able to calculate the success rate of multi-generational space missions. Thanks to the social and breeding…
Launching orbital and suborbital rockets from a high altitude is beneficial because of e.g. nozzle optimisation and reduced drag. Aeroplanes and gas balloons have been used for the purpose. Here we present a concept where a balloon is…
Observations show that the expansion of the Universe is accelerating. This requires that the dominant constituent of matter in the Universe has some unusual properties like negative pressure. This exotic component has been given the name…
Long range observations in the field of astronomy have opened up our understanding of the Solar System, the Galaxy and the wider Universe. In this paper we discuss the idea of direct in-situ reconnaissance of nearby stellar systems, using…
The black hole information paradox is a contradiction between fundamental principles which has puzzled physicists for over forty years. The crux of the problem lies in an assumption about the structure of entanglement across the event…
This essay gives a very general introduction to Schwarzschild black holes. First, it focuses on some of its classical features as solutions to Einstein's theory of gravity. In the second part it discusses briefly some specific quantum…
We estimate the relative likelihood of success in the searches for primitive versus intelligent life on other planets. Taking into account the larger search volume for detectable artificial electromagnetic signals, we conclude that both…
Fermi's Paradox is the contradiction between the fact that it would seem to be highly probable that there are other technologically advanced species beyond the Earth, and the fact that there is no generally accepted evidence for their…
In order to quickly study quantum devices in transient problems, this work demonstrates an analytical algorithm to solve the Hartree potential associated with charge fluctuations in the time-dependent non-equilibrium green function (TDNEGF)…
The era of high precision Cosmology has shown our ignorance about the composition of the Universe. In this context, there has been a renewed interest on Alternative Theories of Gravity. Through the experience of a graviton measured by the…
It is seldom acknowledged the tremendous burden that the Nuclear Age leaves on future generations, and the environment, for an extremely long time. Nuclear processes, and products, are activated at energies millions of times higher than the…
This review, intended for a popular audience, was originally published in the online magazine Aeon on 28 January 2014. It is reproduced on the arxiv with permission. The online version (without references) can be found at…
This is a brief, popular (non-technical) introduction (in Italian language) to the problem of quantum gravity, to the recent perspective of emergent spacetime and to its (potential) realization in the context of group field theories, in…
We discuss three rainbow theories created by Descartes, Newton and Young. The note is written primary for school students.
A brief introduction to gravitational waves, addressing those questions that nowadays more and more frequently arise within a large audience (not only of insiders): what is a gravity wave, how can it be detected and, above all, what impact…