Public health experts and elected officials have emphasized again and again that social distancing is the best tool we have to slow the coronavirus outbreak.

The Centers for Disease Control and Prevention encourages people to stay home. If you must venture out, you should stay at least six feet away from others. The World Health Organization recommends a minimum of three feet of separation.

Scientists are learning about the novel coronavirus in real time, and those who study similar respiratory illnesses say that until it is better understood, no guideline is likely to offer perfect safety. Instead, understanding the possible transmission routes for the virus can help us see why keeping our distance is so important.