The twin paradox: the role of acceleration

J. Gamboa, F. Mendez, M. B. Paranjape, Benoit Sirois
The twin paradox, which evokes from the the idea that two twins may age differently because of their relative motion, has been studied and explained ever since it was first described in 1906, the year after special relativity was invented. The question can be asked: “Is there anything more to say?” It seems evident that acceleration has a role to play, however this role has largely been brushed aside since it is not required in calculating, in a preferred reference frame, the relative age difference of the twins. Indeed, if one tries to calculate the age difference from the point of the view of the twin that undergoes the acceleration, then the role of the acceleration is crucial and cannot be dismissed. In the resolution of the twin paradox, the role of the acceleration has been denigrated to the extent that it has been treated as a red-herring. This is a mistake and shows a clear misunderstanding of the twin paradox.

The Physics of baking good Pizza


Heat transfer mechanisms in the pizza oven

Andrey Varlamov, Andreas Glatz, Sergio Grasso
Physical principles are involved in almost any aspect of cooking. Here we analyze the specific process of baking pizzas, deriving in simple terms the baking times for two different situations: For a brick oven in a pizzeria and a modern metallic oven at home. Our study is based on basic thermodynamic principles relevant to the cooking process and is accessible to undergraduate students. We start with a historical overview of the development and art of pizza baking, illustrate the underlying physics by some simple common examples, and then apply them in detail to the example of baking pizza.


The End of Spacetime

Nima Arkani-Hamed is a theoretical physicist with broad interests in high-energy physics and cosmology. He was educated at Toronto and Berkeley, held a postdoctoral fellowship at SLAC National Accelerator Laboratory, and was a professor of physics at Berkeley and Harvard before joining the Institute for Advanced Study in 2008. He was an inaugural recipient of the Fundamental Physics Prize in 2012, and was one of six physicists featured in the documentary “Particle Fever” in 2014.

Longest Straight Line Paths on Water or Land on the Earth


Longest Sailable Straight Line Path on Earth

Rohan Chabukswar, Kushal Mukherjee
There has been some interest recently in determining the longest distance one can sail for on the earth without hitting land, as well as in the converse problem of determining the longest distance one could drive for on the earth without encountering a major body of water. In its basic form, this is an optimisation problem, rendered chaotic by the presence of islands and lakes, and indeed the fractal nature of the coasts. In this paper we present a methodology for calculating the two paths using the branch-and-bound algorithm.

Longest Drivable Straight Line Path on Earth