what determines the different hour in the world?

Question

In the same Emisphere, there is a huge difference between contries whixch are close.

Answer 1

Every 15 degrees in longitude equals 1 hour in time. Why? There's 360 degrees of longitude to go all around the Earth and one day is 24 hours. 360 divided by 24 = 15
There's only a huge difference if you're close to the poles. The closer to the poles you get, the less space there is between time zones. Also some time zones are different for political reasons. Iceland uses the same time as the UK although they are much further west than where that time zone should end. The international date line is also jagged to prevent parts of the same country from being on a different day than the other.

Answer 2

The Sun takes 24 hours to complete the daily cycle. Theoretically, the reference point is mid-day (12:00 noon) at any place where the Sun is straight on top (middle of the day). This theoretical definition of time will cause innumerable time zones in the world. So for the purpose of ease, the world has been divided into 24 time zones (east to west) for 24 hours, each time zone stretching from North to South pole. The starting reference line (date-line) is in the Pacific ocean.
Each country can decide how to make minor adjustments to the time in a specific time zone that applies only to that country and this adjustment is based on geography/topology such as areas with most mutual interactions (business or otherwise) are put in the same time zone if only a minor adjustment is required. It is also true that the time zone lines are not straight from North to South and may zig-zag across the political boundaries to some extent. Also, some country may decide to shift the time in a particular zone by half an hour to make internal adjustments for some internal ease for the population. Also, remember that some countries may adjust their times in spring and fall for day-light saving but their neighbouring countries may not follow this practice. Also, you may notice that the time lines zig-zag around the islands in the ocean based on the islands political affiliation.
I hope it helps.

Answer 3

Time Zones:

Greenwich, England has been the home of Greenwich Mean Time since 1884. The concept of standard time was adopted to end the confusion that was caused by each community's use of its own solar time.

The need for a standard time was important to the U.S and Canada because of railway routes passing through places where local time could vary by several hours. Sir Sandford Fleming, a Canadian railway planner and engineer, came up with a plan for worldwide standard time in the late 1870's and that's basically the same system that we use now.