Outer space black hole. It depends on who you talk tosome people think its the dimension of time like in donnie darkoothers think its another dimension of space like the designer of. Read cosmology articles and consider how astronomers view the origin of the universe. We are a small group of volunteers who work on space based astronomical observations including cosmic ray gamma ray and x ray astrophysics. But theres something in space that is even more terrifying than any of these something that wipes out everything it comes near.
This is the ask an astrophysicist service of the imagine the universe. What is the fourth dimension.