Is Earth Trapped Inside a Black Hole?

Earth could not have been swallowed by a black hole due to the catastrophic gravitational pull. However, one theory suggests that the Big Bang was the singularity of a black hole in a larger parent universe, and our universe now expands within a black hole that is part of a parent universe. If Earth is within a black hole, it must be an enormous, universe-size black hole, and we would have no way of knowing there was another parent universe in existence.