Why do you think the moons disappeared in the events after Oblivion took place?

Here's my theory:

In an attempt to consolidate support from the Khajiit, the Thalmor deliberately and secretly made the moons seem to disappear for a couple years, then conveniently having them return, leading to the panicked population of Elsweyr to praise the Aldmeri Dominion. This allowing the Thalmor to occupy and build forces in Elsweyr so they can attempt a flank when the Great War begins.

That's the most likely cause, I suppose. However, I'd love it if there was a different cause (perhaps something relating to the Heart of Lorkhan?) and the Thalmor really did save the day

It's possible that the disappearance of the moons isn't connected to the Thalmor at all. I would hazard a guess that their disappearance had something to do with Shezarr's death/ghost/transformation, whatever you want to call it that's happened to him over the years. Maybe Talos has usurped his throne so successfully that every vestige of the Missing God--including his cloven corpse--has been erased from the Aurbis. If that were true, maybe the Thalmor were able to create some sort of illusory facsimile of the moons to gain the obedience of the Khajiit.

I mean, they never had separate orbits before now.

My theory too. If the moons' disappearance wasn't just a massive illusion spell there would've been crazy ramifications on Nirn.

I still like 'it was a dwemer experiment ticking over' best.

To say nothing of the Khajiit.

Since we're swapping pet theories, my pet theory is that an anonymous hero (like the Eternal Champion, the Imperial Agent, the Nerevarine, the CoC, Dovahkiin, etc) started out imprisoned and brought them back and the Thalmor jumped on the bandwagon.

I don't know. But I still want to believe it's something more than just a giant illusion spell. Perhaps MK could come up with something mind blowing?

A psycho robot god-thing from the 27th era ate them, and then spit them back out because they tasted like rotting god flesh.

By Shor, I really hope the disappearance of the moons isn't written off as some petty Thalmor plot to get the Khajiit on their side. It would make that whole event painfully boring. I mean, come on. The moons disappeared! LORKHAN DISAPPEARED FROM THE SKY, YOU GUYS! The mind-blowing potential in that single idea is great, but "it was just a political stunt" is probably the biggest waste possible. And it's far more interesting to think the Thalmor merely stepped in and claimed responsibility so as to appear to be the good guys, when in reality, it just helps to paint them as the bad guys.

It wouldn't even make sense, really. The moons disappeared for two years. If it was the Thalmor, they could have had the same effect if they had just made them disappear for a week, long enough for the Khajiit to totally panic. Two years is way too long.

This. Really, this.

I hope the Khajiit find out they lied.

I don't believe the Thalmor powerful enough to make the moons disapear, even for illusion sakes. However, I do believe them sleazy enough to take the credit for it in some political ploy to sway the khajiit to their side.

You see, Lord Tidus, even a Saxhleel and a Dunmer can agree to someting

I'd agree with this. The Thalmor likely had nothing to do with the moons, they just exploited the opportunity.

Think about what would happen to Mundus if the moons truly disappeared. They're the guardian spirits of Nirn. They could be Nirn's immune system for all we know. The Khajiit are also dependent on the moons for birth form, and without the moons, who knows what the Khajiit would be born as. As it stands there were no crazy occurrences while the moons were gone which leads me to believe that they were never truly gone, just hidden.

What information do we really have on the Void Nights? Is there anything that explicitly says there were no crazy occurrences? From what I can tell, it seems like there is a suspicious amount of no-information on it. It's far too significant of an event to just write off as an illusion, and if that were the case, then I can't understand why they wouldn't present that idea from the start. It seems far too untouched. Ripe for expanding on.

And I'm sure the Khajiit would notice if their children were born as if the moons were there, and wouldn't have praised the Thalmor was much. Something bad happened to the Khajiit those two years...

No, you see, you've contradicted yourself in the very statement of your thesis. The reason the Khajit were, of all peoples, troubled by the disappearance of the moons is because the Lunar Lattice determined the physical features of their race. If it was just an illusion, the Lunar Lattice would not have been effected and their would be no problem for the Khajiit and no reason for them to be thankful. So if the Thalmor were involved, they would have had to physically removed Masser and Secunda from the spheres of the Aetherius.

Basically --- it's the difference between Alteration and Illusion. If the Thalmor did it, it was a form of alteration.

The Mane tried to take the moons and Lunar Elsweyr to a different realm, the Thalmor brought him back. The Khajiit are happy because HEY LOOK, SUGAR!

Or Mysticism

So what happened to the Khajit that were born during the void nights then ?

Mutated abominations?

There is no contradiction. There was no evidence given that the Khajiit were affected in any way besides psychologically. From what we've seen of the Khajiit they're a ritualistic and superstitious bunch, and they wouldn't require anything more than the moons not appearing in the sky to freak out. Again there is no evidence to suggest that the Void Nights actually did anything at all. But the thing about superstition is that it's irrational behavior with its origin based in fact. If the moons truly disappeared the effects on the Khajiit would be disastrous. That's the fact. The Khajiit probably took that initial fact and over the millennia construed innumerable, superstitious omens based on that fact. They probably see cloudy nights obscuring the moons as a bad omen, and the Khajiit merchants traveling Skyrim probably fear sleeping at the feet of mountains that block sight of the moons at night. They were all terrified when the moons "disappeared" locking themselves in their houses at night, hiding under tables, yelling prayers to Alkosh etc. but I don't think anything happened. Fears don't have to be founded for superstition to stay ingrained, especially when that superstition is deeply cultural.

Creatures that even Vivec and Molag Bal's children would fear.

The real reason why the Khajiit panicked is because Moon Sugar comes from moonlight, yes? Then two years without moonlight would devastate the Khajiit via drug withdrawal.

I don't think the term "superstitious" is really well applied to the denizens of TES. Nor do I even see the Khajiit as being particularly superstitious in lore --- if anything, they seem more worldly than the other races, as is seen in their affinity for business and crime.

But anyway, you really have no proof that the Lunar Lattice went on working as normal during those years, nor do I see their being such a strong response from the Khajiit were there not. And the Lattice doesn't just affect superficial characteristics --- as I recall from The Infernal City, some Khajiit are giant panthers who don't speak and are often used as mounts. It's not a matter of superstition for them, but something that determines their very physiology.

The third empire of man had a space station, fought of Dagon every few years, et cetera. The Thalmor obviously isn't powerful enough to have destroyed Lorkhan Outright for two years, but could they have triggered a real disappearance? I see no reason to believe not. Considering that (1) the moons are an illusion to begin with, and (2) there's no real reason for a book in Skyrim to have all the details of the effects of the third most recent near-apocalyptic event, I see no reason to toss this aside as a fake.

So, what caused it? Well, let's consider what has changed since TES IV:

1) The Daedra seem to have become more limited in power. (Black Star, Clavicus's restrictions, Bal's Shrine being tainted, et cetera)
2) Alduin has returned
3) Crystal-Like-Law Fell
4) Someone was born with the soul of a dragon
5) The Thalmor rose to power in Alinor and Valenwood
6) Falenesti stopped moving
7) The moons temporarily disappeared

It seems to me that there has been a lot of heavenly upset recently. After crystal and green-sap (apparently) turned off, only Snow-Throat, Ada-Mantia, and the Khajiit (if they are a tower) stood entirely firm (walk-brass is still in siege mode, after all). The world was vulnerable. The elves were in a position to do something drastic. What they did, we cannot know, but one thing we do know is that when elves get ready to do drastic things, Shezzar likes to step in. The moons are Shezzar's body.

In my imaginings, some sort of epic space battle went down, and while neither of the principle sides profited greatly, other elements had a chance to slip through while the Lunar Lattice's guard was down. The Daedra overstepped, an un-advlterated et'Ada slipped through to become the soul of a mortal, and perhaps the whole process also sped up Alduin's return somehow. In the next few years, Lorkhan turned his fury towards the Daedra, pushing them back further than they had gone before, and the Thalmor got really pissed and redoubled their Lork/Shez/Shor/Talos hate.

I dunno does my point of view bear any solid base by now as Dragon breaks have been classified as scientific brain-fart&mumbojumbo, however during time when Maruhkati Selectives broke the Dragon to Khajiit only constant thing were moons, everything else went bonkers... Is there anything to tell what Jone and Jode were in Aldmeri religion? As it seems that to Khajiit Masser and Secunda are not body of Lorkhan. And what those moons means to Thalmor, are they body or Lorkhan or Jone and Jode?

I just wonder did Thalmor try to unmake what Maruhkati Selectives did, or tried to do.This, if Dragon breaks would still be real thing instead of mix with different calendar-timelines.

EDIT: My post went bonkers becase of Maruhkati, i'm sure of it.