There are specific things it knows that it doesn't know, like explicitly current information. But you can ask it for information that doesn't exist at all and it will happily generate nonsense without a hint that the question might be somehow wrong:
"please give me a history of the best teams in the American Soccer League from 1850-1859 in the form of a short epic poem"
> In 1850, a league was born, The best of soccer to adorn. From '50 to '59, teams did play, with strength and skill, each match a display.
(more verses follow...)
The American Soccer League is a real thing, but it didn't exist until the 1900s, and the snipped poem goes on to describe teams that never existed competing during a time period where the league didn't exist.
"please give me a history of the best teams in the American Soccer League from 1850-1859 in the form of a short epic poem"
> In 1850, a league was born, The best of soccer to adorn. From '50 to '59, teams did play, with strength and skill, each match a display.
(more verses follow...)
The American Soccer League is a real thing, but it didn't exist until the 1900s, and the snipped poem goes on to describe teams that never existed competing during a time period where the league didn't exist.