Indeed, but there is research underway to find evidence:
<< Black holes are extremely dense and compact objects from which light cannot escape. There is an overall consensus that black holes exist and many astronomical objects are identified with black holes. White holes were understood as the exact time reversal of black holes, therefore they should continuously throw away material. It is accepted, however, that a persistent ejection of mass leads to gravitational pressure, the formation of a black hole and thus to the "death of while holes". So far, no astronomical source has been successfully tagged a white hole. The only known white hole is the Big Bang which was instantaneous rather than continuous or long-lasting. We thus suggest that the emergence of a white hole, which we name a 'Small Bang', is spontaneous - all the matter is ejected at a single pulse. Unlike black holes, white holes cannot be continuously observed rather their effect can only be detected around the event itself. Gamma ray bursts are the most energetic explosions in the universe. Long gamma-ray bursts were connected with supernova eruptions. There is a new group of gamma-ray bursts, which are relatively close to Earth, but surprisingly lack any supernova emission. We propose identifying these bursts with white holes. White holes seem like the best explanation of gamma-ray bursts that appear in voids. We also predict the detection of rare gigantic gamma-ray bursts with energies much higher than typically observed. >>
> The only known white hole is the Big Bang which was instantaneous rather than continuous or long-lasting
Even if the Big Bang was a continuous long-lasting process of energy/matter appearing, wouldn't the effects of General Relativity make it look like, from the perspective of observers later on within the Universe, that all the energy/matter appeared instantaneously?
Right... that's why it's a theory. A humorous, non-serious theory, but a theory nonetheless. (Replace with hypothesis if you want to get really pedantic about it)
Absolutely correct... but continue down the path of wild, unjustified speculation... perhaps then "Dark Energy" is nothing more than "Hawking Radiation" as it appears from a perspective within the black hole. :-P
