White Holes: Are they wormholes?

 What are White Holes?

White holes are thought to be a part of the general relativity, where they are hypothetical regions of spacetime that cannot be entered from the outside, but from which matter and light may escape. In this sense, it is the reverse of a black hole. Some theories have been asking whether white holes and black holes are related. When compared to black holes, white holes have properties like mass, charge, and angular momentum. They attract matter like any other mass, but objects falling towards a white hole would never actually reach its event horizon. It's like watching a black hole but the video is playing in reverse.

White holes predicted by Einstein's theory of gravity are most often mentioned in the context of 'wormholes', in which a black hole acts as the entry point to a tunnel through space and time, ending in a white hole somewhere else in the Universe. But this is deeply controversial because Einstein's theory predicts the existence of a so-called singularity at the center of black holes: a state of infinite gravity which would prevent anything from passing through to the white hole on the other side. 

White holes could also constitute a major portion of the mysterious dark matter that's thought to make up most of the matter in the universe. And some of these bizarre white holes may even predate the Big Bang, the scientists suggested that black holes and white holes might be connected in another way: When black holes die, they could become white holes. Although dark matter is thought to make up 80% of all matter in the Universe, scientists do not know what's it made of. As the name suggests, dark matter is invisible: it does not emit, reflect or even block light. These white holes would not emit any radiation, and because they are far smaller than a wavelength of light, they would be invisible. Future research will explore how such white holes from a previous universe might help to explain why time flows only forward in this current universe and not also in reverse.