Just a warning, though all the contents in these videos are fascinating and cutting edge science, everything about blackholes, singularity, big bang are theories that science has adapted today to explain un-answered questions. Just as couple of 100 yrs ago world used to be flat and sun used to revolve around the earth or just till few decades ago when age of universe was nothing like 13.8 billion yrs and the list goes on.....currently we do not have enough knowledge to explain all of the above, these are just well calculated guess..:P