A Black Hole Created Our Universe

Our universe might have originated from a black hole that lies within another universe.
Between Elon Musk's claim that we're all living in the Matrix and the idea that the inside of the Earth is populated by aliens, there are some crazy theories floating around these days. But when scientists from the Perimeter Institute claim that our universe was birthed by a black hole from a previous universe rather than the Big Bang it's hard to deny that there's something convincing about the hypothesis.

The genesis of the idea is this: when scientists create projections for how the early universe looked, they notice that it's hotter and denser the farther back in time you go.
The idea centers on how matter and energy falling into a black hole could in theory come out a "white hole" in another universe. In such a situation, both the black hole and the white hole are mouths of an Einstein-Rosen bridge, popularly known as a wormhole.
Conventionally, scientists thought this culminated in a moment about 14 billion years ago when the entire universe was contained in a single point, or a singularity. We've seen singularities in our universe at the hearts of black holes, and observed that most of the laws of physics start to unravel around them.
With that in mind, theoretical physicist Nikodem Poplawski at Indiana University conjectured that when a black hole forms upon the collapse of a dying star, a universe is born at the same time from the white hole on the other side of the wormhole.
This is an issue for scientists at the Perimeter Institute: "The big bang hypothesis has our relatively comprehensible, uniform, and predictable universe arising from the physics-destroying insanity of a singularity. It seems unlikely."

Instead, some scientists from Perimeter believe that we should be looking at those black holes more closely.

Here's a short video explaining the key ideas:
https://www.youtube.com/watch?time_continue=85&v=-Ro7rprA9EM

In a nutshell, our universe is the product of a fourth-dimensional black hole that exists in another universe. We're living beyond the event horizon, and so are any other universes created by black holes in our "parent" universe.
Where did our parent universe come from?

We're guessing the answer is going to be "a fifth-dimensional black hole," then a sixth, then a seventh, then an eighth...and it's turtles all the way down, as speculative fiction author Terry Pratchett would say.
On the upside, this solves the information paradox created by black holes—all the "information" that makes up the matter consumed by a black hole isn't destroyed, it's converted into part of a new universe. This multiverse hypothesis even bears a similarity to the sci-fi graphic novel Trillium, which revolves around black holes being gates to alternate universes.
Nested universes
Although a black hole forming from a star the size of our sun would only be about 2 miles wide, it does not mean that a universe which might originate from a black hole would stay that small.

"Our universe was small a long time ago and expanded," Poplawski said. "From the other side, one would not see our expansion." Essentially, a black hole could seem bigger on the "inside" than how it looked to someone outside.

If anyone survived a trip into a black hole and emerged in another universe, "it would be a one-way trip," Poplawski noted. The event horizon of a black hole is ?boundary at which nothing inside can escape.

In theory, black holes do lose mass, however, as Hawking radiation — particles that emerge from the vacuum right next to their event horizons. Black holes that lose more mass than they gain are expected to shrink and ultimately vanish. This does not mean any universe at the other end of the black hole would cease to exist, Poplawski explained. "We would just be disconnected from the other universe," he said.