This post contains spoilers for "Ant-Man and the Wasp" and its post-credits scenes, "Avengers: Infinity War" and its post-credits scene, along with speculation about "Avengers 4" and "Captain Marvel," so don't read any further if you don't want these movies to be spoiled.
"Ant-Man and the Wasp" is a great movie about family, and more specifically trying to reunite Janet Van Dyne, the original Wasp whose been trapped in the Quantum Realm for about 30 years, with her husband, Hank Pym, and her daughter, Hope Van Dyne. During this movie, Ava, or better known as Ghost, is phasing. This means that unless her molecules are reset, she can phase completely out of existence, which is where Janet comes in. Since she's been trapped in the Quantum Realm for 30 years, she's been absorbing Quantum energy, leaving her with Quantum healing powers that can heal Ava, and after Janet is rescued from the Quantum Realm, that's exactly what she does, but Ava still needs more help.
So, in the mid-credits scene, Janet and Hank have built a miniature Quantum Tunnel and are going to send Scott Lang, or Ant-Man, into the Quantum Realm to collect more Quantum healing energy to help Ava. Before Scott heads into the Quantum Realm, Janet gives him some basic instructions. These are to avoid the tardigrade field and to stay away from the time vortex. The mission is going just as planned until Scott loses communication with Hope, Hank, and Janet. You then find out that the family had been reduced to dust as a result of Thanos's infamous snap. Scott, completely unaware of what is happening, is now trapped in the Quantum Realm (unless he has a blue disk for his regulator, which is how he escaped in the first "Ant-Man"), but he might not be alone.
Carol Danvers, or better known as Captain Marvel, is known for her travels in the Quantum Realm, and it has been confirmed that we will see her there again, but we still don't know when or how. "Captain Marvel," which premieres March 8, 2019, will be set in the 90s, and Captain Marvel hadn't even been mentioned in the Marvel Cinematic Universe, or MCU for short, until the post-credits scene in "Avengers: Infinity War" when Nick Fury sent her a message right before he, along with Maria Hill, disintegrated because of Thanos's snap. This leaves us with one huge question:
Where the heck has Captain Marvel been for the last 30 years?
Remember that time vortex that Janet warned Scott about in the "Ant-Man and the Wasp" mid-credits scene? Well, this is where it gets important. My theory is that Captain Marvel has found a way to travel in and out of the Quantum Realm, more specifically the time vortex, and is there by choice, which is why Nick Fury called her. If she has, in fact, found a way to enter and exit the Quantum Realm at her own will, she will more than likely be Ant-Man's way back into reality, but that's not where Captain Marvel's importance ends. Her powers include flight, superhuman strength and durability, and energy absorption and manipulation. Yep, you read that right, energy absorption and manipulation. Janet absorbed Quantum energy and came out of the Quantum Realm with powers, and she was just a normal human. So imagine how powerful Captain Marvel has become over the past 30 years while absorbing Quantum energy, considering that one of her superpowers is literally absorbing energy. If this is true, it would definitely make Captain Marvel one of the most powerful, if not THE most powerful superhero in the MCU, and she could even be the Avengers' ticket to reversing the snap and defeating Thanos.
You might be asking how she could reverse the snap since she has no sort of time manipulation power. Well, the answer to that is simple. If she has been in the time vortex for 30 years, she would understand it better than anyone else, and it would also explain why she hasn't aged a day while in the Quantum Realm, but Janet did. We don't know much about the time vortex, but we can assume that space and time don't work the same there, allowing it to possibly be used for time travel. We already know that time travel will be a major component in "Avengers 4," but Captain Marvel could be the key to achieving it, and ultimately defeating Thanos. So, although the "Ant-Man and the Wasp" mid-credit scene was pretty heartbreaking considering that the Pym-Van Dyne family had just been reunited, Janet Van Dyne just mentioning the time vortex could be major news for "Avengers 4," and although it looks like the Marvel fandom has got the future of the MCU all figured out, we still have lots of questions, most of which will be answered if not in "Captain Marvel," then in "Avengers 4," which premieres May 3, 2019.
