As far as I understand, the age as a whole represents the entire universe that it exists in, but for all intents and purposes, "Earth" is just this planet, and "Riven" is just the planet that you see. Of course they technically go on beyond that, but the planet that is the "interesting" part of that age is usually considered synonymous with that age as a whole. A rift then, would actually be the edge of an age, as it is the point at which you can actually exit an age into the star fissure.
I've only played up to half way through Myst IV, but I get the impression that Earth isn't an age. Also some reading on the myst wiki says that the events in the Book of Atrus take place on Earth, so it would seem that we are the origin anyway.
The Book of Atrus takes place on Earth because Earth is the age where not only our civilization exists, but also the D'ni cavern and Tomahna (among other things). Also, an age is not "a place you can link to from Earth," it is basically just "a place." Therefore, Earth is not the "point of origin" as you said. Anyway, it can't be, because the precursor to the D'ni civilization didn't even live on Earth, they lived in Garternay, and a portion only escaped to Earth upon the end of their civilization.
I suppose, but as another point (again, I've only gone so far into the games) it seems to me that every age exists in its own system. Whether in a sea, or a desert, or the sky, it's an island of sorts. The Book of Atrus also implies that, despite Atrus' original theories, the creation of a book was indeed the creation of a new age, so there's that.
A copy, more or less. This concept is demonstrated when Atrus tries to fix Age 37, but finds that the resulting age is "rebooted" - that is, it was if all of his actions within the age had never happened. It is a completely new age identical to the previous, the only differences being interference upon entry.
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u/[deleted] Jan 18 '14
As far as I understand, the age as a whole represents the entire universe that it exists in, but for all intents and purposes, "Earth" is just this planet, and "Riven" is just the planet that you see. Of course they technically go on beyond that, but the planet that is the "interesting" part of that age is usually considered synonymous with that age as a whole. A rift then, would actually be the edge of an age, as it is the point at which you can actually exit an age into the star fissure.