Rafael Nadal (right) shakes hands with Tim Smyczek after winning a match at the Australian Open on Jan. 21. Rob Griffith/AP hide caption

itoggle caption Rob Griffith/AP

Some physicists are pushing back against ideas like string theory and the multiverse. Here, we see a computer-generated image of a black hole, which might, ultimately, be explained by ideas like string theory. Alain Riazuelo/IAP/UPMC/CNRS hide caption

itoggle caption Alain Riazuelo/IAP/UPMC/CNRS

Chicago Cub Ernie Banks, right, told NPR's Scott Simon, left, in 2014 that he had a lot of fun winning games, but the main thing in his life was "making friends." Peter Breslow/NPR hide caption

itoggle caption Peter Breslow/NPR

The Atlanta Hawks' Mike Scott scores over the Detroit Pistons' Greg Monroe in a game Monday. The Hawks are currently leading the NBA's Eastern Conference. Dave Tulis/AP hide caption

itoggle caption Dave Tulis/AP