What did the poet emerson mean by "the shot heard round the world"?

When the poet Emerson said "the shot heard round the world", he was referring to the first shots fired in Lexington, Kentucky.  That was the first "shot" in the American Revolution in which the Colonial Americans fought the British for freedom from Britain.

History is not an exact science. The facts remain the same for all historians to people but their viewpoints always differ by definition, leading to different interpretations.

So, coming into an agreement on historical research is really, really hard, but then again - human society is built on a variety of opinions.