The Unix Time (Timestamp) represents the number of seconds elapsed since the January 1st 1970 00:00:00 UTC.
It is used in all languages of development, all databases and all systems, for several good points:
- only numbers
- easy computing between dates
- avoid local problems of timezone
One (major) problem: it is only comprehensible by computers. Humans must use converters to display a Unix time as an understandable date.
You can test any timestamp (unix time) freely to convert it to a date. You can also convert any date to unix time (timestamp). All the available timezone are available for every conversion.