01/01/1970
64 Most modern system architectures can represent positive (unsigned long) integers as 64 bits. Unix uses Time_T to represent time and maps that to the local system word length. So when 128 bit architectures appear you can just double the following..
2^64 bits can represent numbers up to 18,446,744,073,709,552,000.
So work out the date 18 million,446,thousand,744 trillion, 73 Billion, 709 Million, 552 thousand seconds from Midnight on 1/1/1970.
1 Year contains 1,893,456,000 seconds.
So Unix time on a 64 bit architecture can represent 9,742,367,435 years after Jan 1 1970
Unix time may run out but I sure as fuck won't be around to care.
I think you meant herding.