But if we look further, could we find evidence that we are inside something even more extraordinary, like a black hole?
A compact black hole is so dense that nothing, not even light, can escape its gravitational pull.
Black holes are places in the universe where gravity is so strong that it distorts the time and space around it; once inside, nothing – not even light – can escape.
In one scenario, a black hole could have swallowed up Earth long ago. However, if this happened, the gravitational forces would be catastrophic, according to Gaurav Khanna, a black hole physicist at the University of Rhode Island.
Would time slow down?
When Earth gets close to a black hole, time would slow down. And depending on the size of the black hole, matter could be stretched into shapes resembling spaghetti. Khanna states that even if a planet survives this “spaghettification” process, Earth would be constrained by tiny, dense points where it would be incinerated by unmeasurable pressure and temperature of a gravitational force.
Therefore, we can exclude the possibility of a black hole swallowing up Earth at some point in its history. Khanna says it would be wiped out in an instant. But there is another way Earth could have ended up inside a black hole: It could have formed there.
Khanna says, “A black hole looks like the reverse of the Big Bang explosion… The math seems similar. While a black hole collapses at a very small and dense point, the Big Bang explosion erupted from such a point.”
A hypothesis suggests that the initial Big Bang explosion was the singularity of a larger universe’s black hole. The dense center compressed and compressed until somehow it exploded, and a nascent universe formed inside the black hole.
This theory, known as Schwarzschild cosmology, suggests that our universe is currently expanding inside a black hole as part of the mother universe.
Can universes exist inside universes?
In theory, this scenario means that universes could exist inside universes, like Russian nesting dolls, and traveling back through a black hole – which may be impossible, as even light cannot travel backward – would unlock uncharted realms, Khanna says.
However, this theory is difficult to prove; nothing can return through the event horizon of a black hole.
But if Earth were inside a black hole, experts have some estimates on the size of the cosmic abyss.
Scott Field, an associate professor of mathematics at the University of Massachusetts Dartmouth, says, “If we were inside a black hole, it would have to be extremely large. Earth would not just be squeezed into a black hole the size of a planet or even a black hole the size of the solar system. If that were true, scientists would take notice.
There would be observable signs of the black hole’s rotation. Or we would see subtle distortions caused by extreme gravitational forces – such as time dilation and matter stretching…
For example, if Earth existed within a black hole the size of Earth, humans would experience the effects of tidal forces, such as spaghettification and time dilation, as they move from one point to another on the planet, according to Field, who works on gravitational modeling, including black hole collisions.
So, any black hole that Earth calls home must be immensely large, on the scale of the universe itself, and vast enough that we couldn’t move far or fast enough to detect gravitational distortions, Field says.
According to Khanna, from inside a black hole in the universe, Earthlings “would have no way of knowing if another mother universe exists.” We would know nothing about it. So, at the very least, it must be said that the search for our universal ancestors would be extremely challenging. However, it would be truly fascinating if this hypothesis turned out to be true.
( Source: Live Science )