We live inside a black hole 

In 2017, researchers from the University of Durham in the
UK published a paper suggesting that CMB imprints
(called cold spots) may be evidence of other worlds. The
authors hypothesized that the spots in the microwave
background radiation appeared as a result of a collision
between our universe and another. In general, the spots in
the relic radiation can be considered evidence of the
existence of the multiverse - billions of other universes,
similar to our own, - the researchers write. New, extremely
interesting research adds another proof to the treasury of
the theory of the Multiverse. Its results, Vice reports,
suggest that black holes formed from collapsed universes
generate dark matter, and our own universe may look like
a black hole to outsiders. Note that dark matter is an
invisible substance that accounts for most of the mass of
the Universe - although it does not emit detectable light, it
still exists, since it has a gravitational effect on clusters of
galaxies and other emitting objects in space. Scientists have
suggested that primordial black holes, hypothetical objects
that date back to the early days of the universe, "are a viable
candidate for dark matter." This conclusion was reached by
an international team of researchers from the United States,
Japan and Taiwan in a paper published in the scientific
journal Physical Review Letters in January 2021. And yet,
for now, all of these concepts are theoretical, although
physicists expect new ways of observing with sophisticated
telescopes in the coming years to help answer many
questions.
British theoretical physicist Stephen Hawking, in his
posthumous research paper written with theoretical physics
professor Thomas Hertog, dealt with the theory of the
multiverse. In an article entitled "A Smooth Way Out of
Perpetual Inflation?" Hawking and Hertog suggested that
the rapid expansion of spacetime after the Big Bang could
have occurred repeatedly, creating multiple universes. Their
work is essentially an extension of the Theory of Inflation,
which suggests that before the Big Bang, the universe was
filled with energy that was part of space itself, and this 
energy caused space to expand at an exponential rate. It was
this energy that gave birth to the Big Bang in theory.