How old is the universe in the MCU?

Question

The timescale of history in the MCU has me very confused, for a couple of reasons - but primarily, concerning the history of Asgard and its conflicts.

(Note: I do throw in a few other questions in the middle of this post, but I make sure to annotate them with "this is a different question" or something of the sort so I don't distract / detract from my main question - I just wanted to show my train of thought.)

So, we know from Thor: The Dark World that the Dark Elves existed before the current universe in the MCU - they existed in the total darkness before it. When the universe, and, along with it, the Nine Realms and all of the other parts of the cosmos, came into existence, the Dark Elves sought to return the universe to its previous state using the Reality Stone, a.k.a. the Aether.

Moreover, we also know that the plan Malekith carried out to engage in such "universal correction" occurred during the previous Convergence, when King Bor was ruler of Asgard, roughly 5000 years prior to the present day.

So, if I'm getting my math right, if the universe is indeed as we believe, roughly 14 billion years old, Malekith and his buddies just waited around nearly all of existence to attack Asgard 5000 years ago / 3000 BC? (And for that matter, how long has Asgard been around? Given that the first king of Asgard was Buri, Bor's father, and Asgardians live a couple thousand years, I'm not sure how far back it can go. Though, this is another question entirely.)

So, if the Convergence really did take place every 5000 years, and the universe is presumably much older than that, Malekith would have had various - and I mean various - opportunities to carry out his plan on any of the Nine Realms. And for that matter, given the sheer timescale of existence that we might assume for the universe, and the fact that the Dark Elves have spacefaring ships, they could definitely attack civilizations not linked by the Convergence and carry out their plan that way.

(Quick note: Odin does say that

after eternities of bloodshed, my father Bor finally triumphed, ushering in a peace that lasted thousands of years.

This could be a possible answer to this question - but what does "eternities" mean here? Does Odin mean, like, universe-age eternities? That, for the near-entirety of existence, the Dark Elves were just ravaging the universe? Again, what's the time-scale here? How old is the universe?)

This really only makes sense if the age of the universe in the MCU was comparable to the time elapsing between each Convergence, because the Dark Elves would have ended up on Svartalfheim, which conveniently links to Asgard and other realms they can wreak havoc upon during the Convergence(s). So, either Malekith times his attacks on civilizations for perfect cinematic backstory, or the MCU universe is younger than we expect. (Or I'm missing some other crucial information.)

Answer 1

Firstly to address your title question it would appear that the age of the universe aligns to what we know of our own world. We know that Wong mentions the Big Bang as creating the universe and the Infinity Stones.

Wong: From the dawn of the universe, there was nothing. Then, boom! The Big Bang sent six elemental crystals, hurtling across the virgin universe. These Infinity Stones each control an essential aspect of existence.

_{Avengers: Infinity War}

Ego also tells the Guardians as him being millions and millions of years old meaning that 13.8 billion years old from our world to theirs still aligns.

Ego: Over the millions and millions of years of my existence I have made many mistakes, Peter. But you’re not one of them. Please give me the chance to be the father she would want me to be.

_{Guardians of the Galaxy Vol. 2}

Essentially then the question would be why the Dark Elves didn't act sooner? I think this really boils down to two parts (though I would say neither is a great explanation):

The Aether had to be controlled and created

Note that when the Aether is inside of Jane it defends itself, Jane has no control over it and Malekith appears to want to use it the same way. Presumably he needed to learn to use it first and that might have been no easy feat with it being a somewhat unpredictable Infinity Stone.

Eir: The infection, it's defending her.

Thor: No, it's defending itself.

_{Thor: The Dark World}

This is backed up with Odin's comments immediately after when he's telling the pair of the Aether:

Odin: Come with me. There are relics that predate the universe itself. What lies within her appears to be one of them. The Nine Realms are not eternal. They had a dawn as they will have a dusk. But before that dawn the dark forces, the Dark Elves, reigned absolute and unchallenged.

Thor: "Born of eternal night, the Dark Elves comes to steal away your light." They were these stories mother told us as children.

Odin: Their leader, Malekith made a weapon out of that darkness, it was called the Aether. While the other relics often appeared as stones, the Aether is fluid and ever changing. It changes matter into dark matter and seeks out to host bodies, drawing strength from their life force. Malekith sought to use the Aether's power to return the universe to one of darkness. But after eternities of blood shed, my father Bor, finally triumphed, ushering in the peace that lasted thousands of years.

_{Thor: The Dark World}

It's also worth noting here, as you do in the question, "after eternities of blood shed". This means that the battle has been going on at least a little while longer than just during the Convergence when Asgard finally won as that only lasts for a few minutes, ~7. It's possible the battle has raged on for quite a few Convergences on and off over the years. Asgard too knew when to battle the Dark Elves to stop them using the Aether.

Detecting the Convergence is hard

Heimdall notes in a conversation to Thor that sensing the Convergence coming is difficult. It's not something that just anyone can do.

Heimdall: You recall what I told you of the Convergence?

Thor: Yes, the alignment of the worlds. It approaches, doesn't it?

Heimdall: The universe hasn't seen this marvel since before my watch began. Few can sense, even fewer can see it. A world that's infected can be dangerous. It is truly beautiful.

_{Thor: The Dark World}

It would appear that the Dark Elves may not actually know how to sense it themselves. They only wake up in TDW because Jane touches the Aether and that awakens them. It's possible they're using the Aether to detect it because they can't. If this is the case then they might not have even known about it for a long time.

Malekith: The Aether awakens us. The Convergence returns.

_{Thor: The Dark World}

Answer 2

As far as I know, no explicit timescale has been given as to how old the universe is in the MCU. In Avengers: Infinity War though, Wong briefly mentions the dawn of the universe and the Big Bang, which suggests that the MCU adheres to the Big Bang theory, which in turn suggests that the universe in the MCU is about as old as ours.

WONG: From the dawn of the universe, there was nothing. Then, boom! The Big Bang sent six elemental crystals, hurtling across the virgin universe. These Infinity Stones each control an essential aspect of existence.

So assuming, for the sake of argument, the universe is approximately 14 billion years old in the MCU (as our universe is estimated to be), does that mean the Dark Elves were waiting around for almost all of that time before attempting to revert the universe to a state of eternal night? Well no, because the film clearly establishes that this plan could only be carried out during a Convergence, which involved the alignment of the Nine Realms, including Earth.

And the Aether had to be released at a specific location on Earth too, that being the site of the University of Greenwich in London. So it couldn't possibly have been done until the Earth existed at least.

JANE FOSTER: Malekith is going to fire the Aether at a spot where all the nine worlds are connected.

ERIK SELVIG: Amplifying the weapon's impact. With each additional world, the power will increase exponentially. The effect would be universal.

THOR: Yes, well the alignment is only temporary. He must be in exactly at the right place at the right time.

ERIK SELVIG: The Convergence will be in full effect in seven minutes.

JANE FOSTER: That just means we have to keep Malekith busy for eight.

It's also made clear that Malekith needed the Aether itself to carry out this plan. So when did he get hold of that? That is not made clear, so for all we know, he may only have obtained it around 5000 years ago, shortly before the previous Convergence.

The Guidebook to the Marvel Cinematic Universe - Thor: The Dark World clearly states that the Dark Elves attempted to use the Aether 5000 years ago, and that they were defeated by the Asgardians, led by Bor. There's no clear indication, either within the films or the guidebook, that Malekith ever attempted to use the Aether before that, or that there were any previous conflicts between the Dark Elves and the Asgardians.

Five thousand years ago, during a Convergence of the Nine Realms, the Dark Elf Malekith sought to return the universe to eternal night by releasing the ancient, destructive force of the Aether. Asgardian King Bor and his armies opposed the Dark Elves, defeating Malekith and hiding the Aether.

Sure, Odin did say that there were "eternities of bloodshed" before Bor's victory over the Dark Elves, but if we take that statement in conjunction with all the other information we're given, it seems all but certain that Odin used the term "eternities" very loosely, and that the conflict which occurred 5000 years ago was the first such conflict, rather than the penultimate one in a long series of them.

ODIN: Their leader, Malekith made a weapon out of that darkness, it was called the Aether. While the other relics often appeared as stones, the Aether is fluid and ever changing. It changes matter into dark matter and seeks out to host bodies, drawing strength from their life force. Malekith sought to use the Aether's power to return the universe to one of darkness. But after eternities of bloodshed, my father Bor, finally triumphed, ushering in the peace that lasted thousands of years.

Admittedly, we can't say with certainty that Malekith didn't have the opportunity to carry out his plan during another Convergence prior to the one 5000 years ago, but nor can we say with certainty that he did. So we as the viewers are free to reach our own conclusions in that regard.