This video shows the formation of large scale structures in the universe over its lifetime. When they say “large scale”, they’re not fooling around. Those thin strands of light at the end of the clip? Those are strings of galaxies. The whole image represents about 80 billion galaxies, each containing billions of stars.
What’s happening here is that a nearly uniform distribution of matter is being pushed and pulled by various forces and, over time, tiny fluctuations in that distribution are emphasized, drawing the galaxies into filaments with large voids in between.
What strikes me most about this is how much it looks like, say, strings of melted cheese or burst soap bubbles. Entirely different sets of forces and vastly different scales but with a similar effect.
Something that’s not obvious from the video is that the universe is expanding during this entire time. What we’re seeing is the universe scaled to full-frame, so that we can observe the changes in structure without being distracted by the expansion.
Think of it this way: Imagine you’re standing outside the universe with a camera (technically impossible). And you record a time-lapse video starting at about 13 billion years ago (also impossible). Now, as it expands, you run backwards fast enough to keep the entire universe in frame (again, impossible). If you did all that, you’d have a movie something like what we’re seeing here. Also, you’d only need to come up with three more impossible things before breakfast.