Question

What is a white hole except from black hole?

Answer 1

A white hole is a place where matter would pop out into the universe. (If it could exists with any matter in it)

Answer 2

It's hypothetically contrary to what a black hole is, it does have some mass ( He knows of what type) but a negative interaction with gravitational field, a.k.a. it bulges out the space time fabric, such that nothing can get to it's vicinity, so you or light can't enter it from outside.