Since delving into some very impressive ruins and reading several books, I've taken quite an interest in the Dwemer. It baffles me that such a highly advanced race could suddenly disappear. There are many theories on this and frankly I don't know what to think, so I'm curious what you believe happened. Did the Dwemer bring about their own extinction? Was it aliens? Something else entirely? I want to hear your thoughts on the Dwemers' vanishing act.

http://www.imperial-library.info/content/final-report-trebonius

They seem to have turned themselves into a big stompy robot.

The skin thereof.

They tried to become the skin of http://suvudu.com/files/2010/10/Megatron.jpg

That didn't work to well.

They actually did succeed in that endeavour.

Edit: even though that wasn't there goal.

I find only one thing that conflicts with this theory.

Dwemer Ghosts.

Oh yes, and also that Numdium was used by everyone's favorite Breton, Tiber Septim. If it was still here, then how could the Dwemer used it to return to Pre-Existnce?

Because ectoplasm was essential ?

Because they failed ?

I don't trust the idea that Numidium was meant to uncreate itself. The report misinterprets a line that says "Most Dwemer didn't believe that they were subgradients" to be "Most Dwemer didn't like the fact that they were subgradients", and if they were to unmake themselves, then why does Numidium seem to have been meant to move on it's own power, judging by it's humanoid form and the engraving described in "Ruins of Kemel-Ze" (Which depicted Numidium emerging from Red Mountain)? Besides, the Dwemer are so radically different from other Elves that I don't think that they would share their goal of ascending to pre-creation.

Dwemer ghosts are the ghosts of Dwemer that died before the disappearance.

Numidium did not become active when the Dwemer became its skin. The "why" of that is what is the real mystery.

Ohhh, I get ya know.

Thought you meant that they did suceed in returning to the time before time.

Azura messed some [censored] up.

Like, when you're super illegally speeding on the motorway, the slightest bump will send you on a terrible crash course into something.

But, we'll never know, because Azura is confusing mofo, and will never tell anyone.

I doubt that Dwemer were trying to do the whole unmaking thing, that's the Altmer's schitck.
But they did believe themselves better than the so-called "gods" and were going to prove it.

They pissed off the Admin's of Mundus and got perma-banned from Nirn

The sub-gradients attempted to become pro-gradients and failed miserably.

Or maybe the suceeded.

I like to imagine they were transported backwards through time. With all their knowledge, hence why they advanced their technology so quickly; to the time when the ehlnofey walked nirn and were seen as dwarves to them. They built thousands of fortresses and ruins, then during the first era, they attempted to ascend mortality, only for it to fail. Resulting in them being thrown back in time...somehow. Then the cycle starts again...

They succeeded in gaining divine power. Unfortunately, they did so using the power of a dead creator god, and thus all died themselves and became part of creation through the Brass Tower. Really, they should have thought that part through.

And here again is another story of the Elder Scrolls by me.

Kagrenac very cautiously moved each finger in turn. The many moving parts of his creation the Wraithguard whirred and altered as needed, reacting to his musculature. He, slowly then quickly, opened and closed his fist.

Mztand, his assistant, Moved the two boxes up to her mentor. He silently nodded and threw the braids of his beard over his shoulder, where they were secured by twine. He could feel the thrum of the Heart's beating. Copper and ebony cables connected the Heart to the inside of the great machine they had created.

"Power at 40%, sir." Bcharn said, shutting down his magicomputer. "All is ready for you."

Kagrenac reverently opened the first, smaller box, and placed the knife upon the brass table. Keening glinted white, despite the only lights in the room being the yellow glow-wires and the red of the lava far below in the core of the Mountain, where creatia whirled in liquid form. He opened the other box and took out the hammer. With this, the Dwemer genius approached the Heart.

"The Chimer have reached the gates of the fortress, the but the battle goes well." Their Diviner, Krunak, said, his eyes moving left to right. "Dumac may not know the genius of this plan, but he is a skilled tactician."

Mztand laid the control mechanism next to Keening, as instructed. Kagrenac struck the Heart with mighty Sunder. All present felt the great beat of the heart now, as though it was their own. Kagrenac took up Keening and opened his mind, the Dwemer telepathy linking him to every one of his kind before he struck.

Then all Dwemer, all Dwemer save the one he called the Explorer Yagrum, became at last as one in the sorcerous Brass skin of his creation, a Tower that he himself had made, his single greatest achievement...

Their thoughts began to bleed together, and the last individuated thought Kagrenac had was "Oh balls, I left the control mechanism outside!"

Unity.

The End.

And that's how the Dwemer disappeared.

I'm not willing to accept any theory with lines like "they should have thought that part through." The whole point of the Dwemer is that they were uber-geniuses capable of dividing by zero, and Kagrenac is praised as one of the smartest among them. I can accept the idea that maybe he acted too soon with using the Tools on the Heart. After all, it was a pretty hectic time. Maybe he didn't have time to call Yagrum out of the Outer Realm, and since he didn't go with the Dwemer, that's why Numidium remains inactive. Or, perhaps Yagrum was intentionally in an Outer Realm, so that he could flip the On switch on Numidium, but he caught corprus and lost that memory.

Regardless, I hate to think that the Dwemer's disappearance was because they just didn't think something through. It kind of discredits them as a super-intelligent race.

That's why I like my "left the keys outside" idea. They say a genius is so busy comprehending the fantastic that they can barely see what's under their noses, so it would make them, and kagrenac especially, show both the good and bad sides of genius.

And that's precisely why I do like that idea.

Kagrenac at the Battle of Red Mountain discovered that his existence is but a mere fraction of another's entire mind,
he faced self doubt and decided to become a bigger piece of pie, using his tools and his race's total telepathic link,
attempted to morph the dwemer race into a godskin of the Brass God Numidium. However- between this, he ZERO-SUMMED.

And thus most of the whole dwemer race followed suit. The Heart of Lorkhan tried to connect the ritual but could not find the source.
So instead it filled up the ruin's shells (which looked like dwemer) and acted as a localised power source or battery for them, untill
they completed the connection, the ritual, the network-merging. It as well filled up the Numidium's skin with an amount of power.


This theory's best evidence would be the centurion dynamo cores, they are filled with red-like energy which glows when life comes near.
I believe this is a network anti-virus- if an interruption to the merging process is detected, the localised sentinels will seek, quarantine, then destroy.
Lorkhan's Heart and much of Red Mountain share the red glow in-fact, definitely hinting upon some connection between them and the cores.
There is also a book which details about a centurion, when taken away from vvardenfall, goes completely inactive- when taken back, goes active.

The centurions of Skyrim I believe, rely on another source of power. Perhaps the Eye of Magnus (it does appear as a great source of power on the dwemer oculory).
Or through some crazy-mimical energy tapping, the Dovahkiin by just being present in Skyrim has established an external router connection for the heart.
But maybe it could be simpler than that- the Heart could of just moved through various lava streams to be present in an underground volcanic area within Skyrim.

My theory is caveman style: Dwemer all liked the space beneath winterhold. They dug too deep, and the great collapse ensued. Dwemer all crushed. The end. ...yes I know it is quite wrong

I've been thinking about it, not all the of the dwemer might be gone in a way, there is definately the one in the corpusarium but reading a lot of the books found in game there were dwemer spread all over from Morrowind to High Rock. One book in particular explains there is a possible connection between Dwemer and Altmer customs like law and that there might have been some outcast Dwemer clans because of a difference in values like that.
What I find interesting about it is before the transformation of the orcs their chief diety was at the top of the Altmer pantheon until Boethiah curses the orcs into a new form like Azura did to the Chimer. So naturally the Orcs are great smiths much like the Dwemer. Coincidence? There isn't much written about orcs history before 1E700 when the Dwemer disapeared although I think they showed up before then I like to think it's possible they were a ousted dwemer clan that were transformed and survived the rest of the dwemer extinction because of the change.
Maybe this is just non-sense was just a fun thought to me since both Orcs and Dwemer had these secretive closed in societies and possible alliances from time to time.

Seriously, it's been forever now. Heck, this was answered before this forum came to be, so it has been answered a very long time ago, and there has been nothing to contradict this. Hell, the side quest in the College of Winterhold semi-confirms this in-game.