EST vs MST
EST and MST refer to two different time zones. Earth is divided into different time zones and EST and MST are two of the 24 time zones that our planet has been divided into. Difference between EST and MST can be understood by understanding the concept of time zones. If you think of earth as a spheroid and draw 24 wedge shaped sections , all parallel to each other and 15 degree of longitude apart, you will get 24 zones each having their own time known as local time all over the zone. This local time in neighboring zones will differ by one hour to make up 24 hours of a day.
However, this is a very simplistic concept, and in reality it is not possible to divide earth into 24 time zones so easily (as if you slice a rubber ball into 24 parts). These zones are not regularly divided because of political boundaries and geographical discontinuities. This is why in some time zones; half an hour difference between extremities is commonly observed. These time zones are based upon Greenwich Mean Time (GMT), which is a place in UK, situated at 0 degree longitude, or the prime meridian. GMT is also called Coordinated Universal Time.
Among the time zones, Eastern Time Zone is observed in the region that is east coast of North America. It is also known as North American Eastern Standard Time (NAEAST). This time zone is referred to as ET in US and Canada. While Ontario, Quebec, and East-Central Nunavut are part of EST, 17 states and Columbia fall completely in EST in the US. Another 6 states are divided between EST and central Time Zone. This time is called Eastern Standard Time in winters and Eastern daylight Time (EDT) in summers.
During the shortest days of autumn and winter, North America keeps time using Mountain Time Zone. This is done by subtracting 7 hours from GMT. Six hours are subtracted from GMT during daylight saving time in spring, summer and early spring. This time zone is also called Mountain Standard Time or MST in winters and Mountain Daylight Time (MDT) when observing daylight saving time. This time is one hour ahead of Pacific Time Zone and one hour behind Central Time Zone, and both UTC-7 and UTC-6 are based on mean solar time of 105th meridian of Greenwich Observatory.
Thus we can see that while MST is UTC-7 and UTC-6, while EST is UTC-4 and UTC-5. Though many important cities of the US such as Phoenix and Arizona and the states such as New Mexico, Wyoming, Utah, Idaho, Kansas, Nevada, Montana, Nebraska and Texas follow MST, the capital of the US follows EST, and this is why it is called the official time in the US and events and television programs base their programs using EST.
The world is divided into different time zones and EST and MST are two of the 24 time zones
EST is UTC-5 and UTC-4, while MST is UTC-6 and UTC-7 depending upon weather
MST is based upon 105th Meridian west of Greenwich Observatory, while EST is based upon 75th Meridian west of Greenwich Observatory.
Though many states of US follow MST, EST is the standard time in the country as it is followed in the capital.