Want to have your brain blown for a few minutes today? Dip your head in some physics, and realise that there's no such thing as pink. Scientifically speaking, that is: it's just something our brain makes up.
MinutePhysics puts it in predictably concise terms: all colours correspond to wavelengths of light. But there's no wavelength in there for pink! Instead, it's a combination of neural trickery -- our brains strip green out of the spectrum to fill in for pink. Brains! Now how does that make you feel about this week's shooting challenge? [MinutePhysics]