Final answer:
The abbreviation of the Greenwich meridian is GMT, which stands for Greenwich Mean Time. GMT is a global time standard equivalent to UT, UTC, and Z and is essential for coordinating international time zones and global operations such as air traffic control.
Step-by-step explanation:
The abbreviation of the Greenwich meridian is GMT, which stands for Greenwich Mean Time. GMT is the mean solar time at the Royal Observatory in Greenwich, London, reckoned from midnight. It is used as a global time standard. This time measurement is historically important for two reasons: the prime meridian defines the universally agreed Zero Longitude, and GMT is used as the basis for calculating time differences around the world.
Greenwich Mean Time is the same as Universal Time (UT), Coordinated Universal Time (UTC), and Zulu Time (Z). All these terms refer to the local time at the prime meridian (0 degrees longitude). This time standard is essential for various global operations, including military operations, international radio broadcasts, air traffic control systems, and the coordination of flights across different time zones.
A meridian, also known as a line of longitude, is critical for determining time zones worldwide. An accurate clock set to Greenwich time can determine longitude by comparing the local solar noon to the time in Greenwich. If the sun is at its highest point and your clock reads 3 p.m. GMT, you would be at 45 degrees west longitude because the sun passed the meridian in Greenwich three hours ago.