Longtitudes are Imaginary vertical line that run through middle of the Earth from North to South and South to North.
Longtitude is derived from Latin Word “Longus” which means Long.
The longest Longtitude is “Prime Meridian” which separates the Earth into Eastern and Western Hemisphere.
Longtitudes are also called as “Meridian”, because they are running vertical to the Prime Meridian.
Lines of Longtitude form semicircle around the Globe.
There are total of 360 longtitudes.
Longtitudes are measured in Degrees,Minutes and Seconds.
Longtitudes are used to determine the Time Zones.
1.What is GMT?
Greenwich Mean Time.The zero degree longitude Prime Meridian it passes through Greenwich near London in United Kingdom.It is used as a base to calculate the Time Zone around the world.
2. Any place around the World can be chosen as zero degree Prime Meridian but why Greenwich was chosen?
Based on Royal Observatory Sir.George Airy 1851 proposed Prime Meridian in Greenwich. In 1884, Greenwich was voted as Prime Candidate by Elite group of Astronomers in International Meridian Conference.
3. What is IST?
Indian Standard Time. The 82.5 degree longtitude that passes through Mirzapur near Allahabad in Uttar pradesh is chosen as IST. It is used to calculate the Local time for India and Sri Lanka.Indian Standard Time is 5 hours and 30 minutes ahead of GMT.
4. What are Time Zones?
During Earth’s Rotation one half of Earth receives the Sunlight,while the other portion is dark. So there will be confusion whether it is a.m or p.m, to avoid this Scientists proposed the Time Zone concept.
5. Who first proposed the concept of Time Zones?
Sir. Stanford Fleming in 1878 proposed the Time Zone.
6. How are Time Zones are calculated?
Time Zones are calculated according to Earth’s rotation with respect to Sun.The Earth take 360 degree in 24 hours. So for one hour Earth moves by 15 degree. (360/24 =15 degree) So Scientist divided the Earth into 24 zones. For each zone time is calculated accordingly.
7. What are the factors responsible for change in Time Zone?
Sunlight = Due to Earth’s rotation one part of the Earth receives sunlight while the other half is dark. This determines the Day and Night,which is one of the major factor responsible for change in Time in each zones.
Longtitudes = Each Country is located in different Longitude regions,this determine change in Time for each zones. Ex: When it is Day in INDIA it is Night in United States.
For Ex: In India only 82.5 degree Longtitude alone passes through Mirzapur near Allahabad. So there is only One Time Zone for India and Sri Lanka.
France has got 12 Time Zone.( This means more longitudes passes through France since it has more territories)
United States and Russia have 11 Time Zones.
8. How are we calculating Date and Time using Latitudes and Longitude?
International Date is Calculated using Imaginary Arbitary line that run from North pole to South Pole.It is approximately 180 degree Longtitude passing through Mid Pacific Ocean.
This Imaginary Line is drawn through the Sea,to avoid the Date Confusion.
When we cross this line the Date and Day changes.
For Ex: India is located in the Eastern Hemisphere.So when we travel West, the Date and Day increases by one.
9. What are Global grids?
Global grids is the network formed by the intersecting lines of Latitudes and Longtitudes. Global grids enable to locate a place quickly. Ex: Google Maps.