The quote means "the shot" had an impact all around the world and everyone in the world paid attention to the event.
The quote "the shot heard round the world" refers to the first shot of the American Revolution that took place at the battles of Lexington and Concord. Historians are unsure who fired the first shot of the American Revolution. There is one thing for certain, historians agree Lexington and Concord are the first battles of the American Revolution. The beginning of this war brought attention from the rivals of Great Britain as they watched a colony battle their mother country. Emerson describes the event as one that was newsworthy and had an impact all around the world. Before the war is over, other countries would get involved in the conflict and after the colonies of the Americas would be inspired to revolt against their own mother countries.