black hole doubts

Question:
if matter or energy can neither be created nor destroyed ,what changes is happening in blackhole.?


Answer Till Now:
Simply put , a black hole is region of super dense matter. The mass density is high enough that the gravitational field intensity increases almost exponentially as the centre of the black hole is approached.
A black hole can be viewed as a compressor as all mass/energy that is captured by its gravitational field remains there. Initially it was thought that Black holes would be everlasting objects as they just swallow anything that comes close to them and hence will keep on growing. Dr. Hawkings however has changed this perception and we now understand that even Black Holes decay via emission of what is called the Hawking radiation. This rate of radiation is very slow but eventually, even a back hole will radiate away.
Thus mass/energy is always preserved even in a Black Hole.


query:
is there something called white hole?