and mining and meeting recently the bitcoin and watching the boost it currently has many questions arise about the stability of the currency in the short or long term , but with the release of new ASICs and power of hash, and my questions are as follows .

If I assume that when you start distributing the new ASIC in a theoretical case to see that a millionaire is a good investment decides to spend about 5 million in equipment for mining, or suppose a government or banking group decides to try to boycott the bitcoin decided to invest a few million to acquire or manufacture equipment for mining massive , and maintain control of the currency , it could be the case that people who have invested hundreds or thousands of dollars in new equipment , the next day by the ability to earn 0.0001 acquired by the above that absolute produscan lost them ?

And my second question is: what is the formula to calculate the difficulty of bitcoins if you reach a certain amount of hash in mining?