The universe of TES is technically a geocentric system, not solar. It would be hard to make an Empire of the Sun because it's just a giant hole to another realm. Unless you want to consider people traveling and conquering pure magic. Improbable, but probably not impossible and highly debatable material.

Done:
According to Hestra, Cyrodiil became an Empire across the stars.

That Tamriel's just another tributary of the immortal time-river.

Though the improbability of it would distinguish that Tamriel from any other space opera hack. I like where Mimehose is thinking about Lucas' original draft. I don't know much about Firefly, except it's western motif, but Cyrus reminds me of a John McClane pirate cowboy. I don't really know what aesthetic would suit Tamriel in space.

Even in space, Tamriel is as sci-fi as the Dwemer were steampunk. TES is fantasy.

I think I prefer:

Imagine Bethesda abandoning Nirn's safe canopy. I can hear the outcry.

Any source or factual backing to this? I'd like to see it. If it's in a game, I have and have played all of the TES games except Redguard and Battlespire, and the Travels games. If it's on TIL or UESP, please show me a link.

Pocket Guide to the Empire, Third Edition: http://www.imperial-library.info/content/pocket-guide-empire-third-edition-magic-aetherius
MK's Imperial Census of Daedra Lords: http://www.imperial-library.info/content/imperial-census-daedra-lords's listing
Plotline of http://www.imperial-library.info/content/elder-scrolls-legend-battlespire-storyline: In the first part of the walkthrough titled "Weir Gate," I found at least two references to space. One a scamp mentioning a "busted magic boat" and a http://www.imperial-library.info/content/letter-mactana-greenway.
http://www.imperial-library.info/content/forum-archives-michael-kirkbride

There's probably more links others can find for you. I'm sure I've missed a few.
Some stuff may be open to personal preference on whether you wish to take it as canon or not.

Okay, thanks - I just never heard anything like people going to space in the TES universe before, that's all.

Orcs with space helmets!!

Well this was an interesting reading. I have played every game of the series and i didn't know the sun was a hole to another dimension let alone Aetherius... I have to read more books when i replay the games >_> Damn i feel like a noob

Haha, I agree!

Meh, it's been done before. And it needs more dakka.