Not everything counts from 1970. Its the standard time of Unix.
Unix time, or POSIX time, is a system for describing points in time,
defined as the number of seconds elapsed since midnight proleptic
Coordinated Universal Time (UTC) of January 1, 1970, not counting leap
Early versions of unix measured system time in 1/60 s intervals. This
meant that a 32-bit unsigned integer could only represent a span of
time less than 829 days. For this reason, the time represented by the
number 0 (called the epoch) had to be set in the very recent past. As
this was in the early 1970s, the epoch was set to 1971-1-1.
Later, the system time was changed to increment every second, which
increased the span of time that could be represented by a 32-bit
unsigned integer to around 136 years. As it was no longer so important
to squeeze every second out of the counter, the epoch was rounded down
to the nearest decade, thus becoming 1970-1-1. One must assume that
this was considered a bit neater than 1971-1-1.
Note that a 32-bit signed integer using 1970-1-1 as its epoch can
represent dates up to 2038-1-19, on which date it will wrap around to
Why is 1/1/1970 the “epoch time”?