Effects of exoplanetary gravity on human locomotor ability

Nikola Poljak, Dora Klindzic, Mateo Kruljac
At some point in the future, if mankind hopes to settle planets outside the Solar System, it will be crucial to determine the range of planetary conditions under which human beings could survive and function. In this article, we apply physical considerations to future exoplanetary biology to determine the limitations which gravity imposes on several systems governing the human body. Initially, we examine the ultimate limits at which the human skeleton breaks and muscles become unable to lift the body from the ground. We also produce a new model for the energetic expenditure of walking, by modelling the leg as an inverted pendulum. Both approaches conclude that, with rigorous training, humans could perform normal locomotion at gravity no higher than 4 gEarth.
Read more at https://arxiv.org/pdf/1808.07417.pdf


Upper limit on the Stiffness of space-time

stiffnessAdrian Melissinos
From the recently observed propagation of gravitational waves through space-time an upper limit can be deduced for the stiffness of space-time through which the gravitational wave propagates. The upper limit is extremely weak, implying that the stiffness of space-time is at least 14 orders of magnitude weaker than that of jello.
Read more at https://arxiv.org/pdf/1806.01133.pdf


Physics Needs Philosophy. Philosophy Needs Physics

Carlo Rovelli
Contrary to claims about the irrelevance of philosophy for science, I argue that philosophy has had, and still has, far more influence on physics than is commonly assumed. I maintain that the current anti-philosophical ideology has had damaging effects on the fertility of science. I also suggest that recent important empirical results, such as the detection of the Higgs particle and gravitational waves, and the failure to detect supersymmetry where many expected to find it, question the validity of certain philosophical assumptions common among theoretical physicists, inviting us to engage in a clearer philosophical reflection on scientific method.
Read more at https://arxiv.org/ftp/arxiv/papers/1805/1805.10602.pdf

Investigation of Skyscraper’s Feat

(original version with an addendum)

Costas Efthimiou
Skyscraper is a Hollywood action film directed and written by Rawson M. Thurber scheduled to be released on July 13, 2018. We present an exhaustive analysis of the feat shown in the recently released teaser poster and trailer of the film. Although the feat appears to be unrealistic at first glance, after close investigation using back-of-the-envelope calculations, it is seen to be within human capabilities.
This article is the original version of an abridged article published in Physics Education. It was written very soon after the poster and clip were released by Universal Pictures.
Read more at https://arxiv.org/pdf/1805.09643.pdf