How things become bigger or smaller reveals a lot about them. How big can a city get and still be a city? What about a classroom? Can a “theory of everything” describe our universe at all possible scales? “How much,” we learn, is often just as important as “why” or “how.”
- The Trouble with Theories of Everything: There is no known physics theory that is true at every scale—there may never be, by Lawrence Krauss
- Why Alien Life Will Be Robotic: If life off Earth exists it has probably transitioned to machine intelligence, by Martin Rees
- Will Quantum Mechanics Swallow Relativity?: The contest between gravity and quantum physics takes a new turn, by Corey S. Powell
- This issue also includes contributions from: Philip Ball, Kevin Berger, K.C. Cole, Andrew Curry, Jessica Green, Jeremy Hsu, Roberto Kaz, Adam Kucharski, Alan Lightman, Moises Velasquez-Manoff, Amy Maxmen, George Musser, Barbara Oakley, James O’Dwyer, Siobhan Roberts, Chip Rowe, Robert Sapolsky, Michael Segal, Scott Solomon, Max Tegmark, and Roger Trigg.