Originally Posted by
ls-
Well, ESO shares the universe w/ the rest of TES series.
There's a plane(t) for each of Eight Divines or Aedras, Akatosh, Arkay, etc, and then there's Nirn, our plane(t). Technically, planets in TES universe aren't the same as in ours, they aren't exactly astronomical bodies floating in space, they're smaller planes within an infinite plane surrounded by the Void, but because mortals can't really wrap their heads around said concept they're portrayed as planets. Theoretically, all plane(t)s are infinite in size, Nirn might or might not be unique in this regard, it's not exactly known if it's finite. And the same could be said about Daedric realms or Oblivion planes as well, they've never been observed from the outside, but in lore Meridia's plane is described as a "sphere".
As for known continents, besides our Tamriel there's Akavir, Aldmeris, Atmora, Lyg, Pyandonea, Thras, and Yokuda.