England's Royal Observatory in Greenwich (the source of Greenwich Mean Time - GMT) is 0 degrees longitude and the reference point. 120 degrees East is the longitude of the east coast of Taiwan. At that longitude, 1/3 of a circumference from Greenwich, the standard time (and date) should be 8 hours ahead of Greenwich. So if it is 4am in Greenwich, it should be noon in Taiwan.
As you move east from the Prime Meridian, time increases by one hour for every 15 degrees of longitude you cross. This is because Earth rotates 360 degrees in 24 hours, so each hour represents 15 degrees of longitude.
15 Degrees per hour
It is 2pm. Every 15 degrees of longitude is a different time zone, since there are 360 degrees of longitude on Earth and 24 hours a day (360/24). Here, there is a 90 degrees difference in longitude, and therefore a 6 hours difference (90/6). The time gets later as it approaches the International Date Line from the east, therefore, since 150 degrees east is east to 60 degrees east longitude, the time is 6 hours after it.
The prime meridian is at 0 degrees longitude, and each 15 degrees of longitude represents one hour of time difference. Therefore, a location at 77 degrees east is 77/15 = approximately 5.13 hours ahead of GMT. When it is 2 PM at the prime meridian, it will be around 7:08 PM at 77 degrees east.
If it is 10 am at 45 degrees W longitude, it is 4 pm at 45 E longitude.
One hour equals 15 degrees.
If it's noon in Greenwich (0 degrees longitude), then at 60 degrees east, it would be 3:00 PM. This is because the Earth is divided into 24 time zones, each representing 15 degrees of longitude, meaning each hour corresponds to 15 degrees. Thus, 60 degrees east is four hours ahead of Greenwich Mean Time (GMT).
The Earth rotates at the rate of roughly 15 degrees of longitude per hour.
There are fifteen (15) degrees of longitude per time zone. (15 degrees x 24 zones = 360 degrees around the planet)
A location's standard time is whatever the local national government says it is. Usually a location's offset from Coordinated Universal Time (UTC) is its degrees of longitude multiplied by 4 minutes/degree (4 minutes per degree) then divided by 60 minutes/hour and rounded to the nearest whole hour, but there are exceptions. Places east of the prime meridian (0° longitude) and west of the international date line (180° longitude) are ahead of UTC, and places west of the prime meridian and east of the international date line are behind UTC.
The person living 4 degrees longitude east of the noon meridian would experience solar time that is 16 minutes ahead of the time at the noon meridian. This is because for every 15 degrees of longitude, there is a one-hour difference in solar time.
15 degrees because for every 15 degrees of longitude that you move, you enter a new time zone. As you move west, you gain an hour; as you move east, you lose an hour. There are 360 degrees on the Earth, which divided by 24 hours in the day, give 15 degrees of longitude per time zone. You can calculate the time by knowing the longitude of two locations and a time at one of them. By measuring the difference in longitude and dividing it by 15, you arrive at the time of the second location.