The phrase "uncharted world" refers to a place or situation that is unknown or unfamiliar, with no previous information or knowledge about it. Full definition
As if that achievement were not impressive enough, scientists are already plotting New Horizons's next move, seeking uncharted worlds beyond Pluto for the craft to study close - up. (scientificamerican.com)
And with Dawn, we're exploring some of the last uncharted worlds in the inner solar system. (discovermagazine.com)
On the three scientific voyages he led between 1768 and his violent death in 1779, English Navy Captain James Cook explored and mapped vast regions of the previously uncharted world, filling in with astounding accuracy fully a third of the globe. (bookpage.com)