GMT/UTC Clock

Greenwich Mean Time (GMT) is an old name for (Coordinated) Universal Time Clock (UTC) it's called Greenwich Mean Time because it's the time at Greenwich in England Time Zone 0 all other time zones are derived from this time zone. In Sydney, Australia for example the time zone is +10 so it's ten hours ahead of this time in Greenwich the time in California, America for example the time zone -7 it's seven hours behind this time in Greenwich. "Zulu Time" is UT1 it's NOT GMT/UTC time and it's not the time shown here either "Zulu Time" or UT1 is the time at the equator a place known as "Null Island" longitude 0 and latitude 0 Greenwich is actually 51 degrees long and 0 degrees latitude so it's not the same place.