In addition to exhaust pollution (“Curb motorcycle pollution,” Oct. 16), the noise caused by motorcycles, and other vehicles, mufflered to emit the most noise possible is equally obnoxious.

We need to think about the purpose of noise in our daily lives and environments. Chris Stokel-Walker discovers a great guide ...

It turns out that impurities and noise aren’t always bad things. We are always amazed that we live in a time where we are learning about the universe at such a fine level of detail.