The equivalent in the United States of 12:00 PM Pacific Standard Time is as late as 3:00 PM Eastern Standard Time and as early as 9:00 AM Hawaiian Standard Time. It is 2:00 in the afternoon in Central Standard Time and 1:00 in the afternoon in Mountain Standard Time. The time is 11:00 in the morning in Alaska Standard Time and 10:00 AM according to Hawaiian-Aleutian Standard Time.
There are 24 time zones in the world, 25 if the International Date Line is considered. In theory, each time zone consists of 15 degrees of longitude and varies by one hour from the previous one, but the boundaries of a time zone are often irregular to accommodate international borders.
Time at the Greenwich Meridian, located at approximately 0 degrees longitude in the United Kingdom, is the time standard for the world. If it is 12:00 noon Pacific Standard Time, it is 8:00 PM at the prime meridian.
The International Date Line is located at about 180 degrees longitude. The time just east of the International Date Line that corresponds to 12:00 Pacific Standard Time is 8:00 in the morning. Just west of the International Date Line it's 8:00 in the morning of the next day. Time on the continent of Australia, corresponding to 12 noon Pacific Standard Time, varies from 4:00 in the morning to 7:00 in the morning of that next day.