Social-distancing guidelines to stay 6 feet from others may be woefully inadequate, one scientist warns — saying the coronavirus can travel 27 feet and linger for hours. MIT associate professor Lydia Bourouiba, who has researched the dynamics of coughs and sneezes for years, warns in newly published research that the current guidelines are based on outdated models from the 1930s. Rather than the assumed safety of 6 feet, Bourouiba warns that “pathogen-bearing droplets of all sizes can travel 23 to 27 feet.”