"Hooray... finally this year me, Mama, and Papa can have a vacation to Switzerland! I'm delighted, and I want to video call Grandma in Indonesia. Eh, but how come mom forbids it, she said Grandma must be asleep.
Then I asked, "It's still afternoon here, mom; how come grandma is already asleep?" Mom also replied that in Indonesia, it is already night.
I asked again, "how come, ma?"
"That's because the time in Switzerland and Indonesia is different, dear."
From there, I was confused. How can it be noon in Switzerland right now, and in Indonesia is night?"
All because of the earth's rotation
So, if you girls have the same confusion, the answer to this is the time difference!
So, what causes the time difference in the world? And why does one country have a different time than another?
The time difference is due to the earth's rotation or the earth's rotation on its axis. Earth rotates 360 degrees in 24 hours, aka in one day.
This rotation causes part of the earth to be exposed to sunlight and experience daytime. While the part that is not exposed to sunlight experiences night.
It is the things above that cause the time difference in the world.
The time difference in Indonesia
"Then do all places in Indonesia have the same time or not?" I asked again, curious.
The answer is "no."
In Indonesia itself, time is divided into three, namely Western Indonesian Time (WIB) which covers the regions of Sumatra, Java, Madura, West Kalimantan, and Central Kalimantan; Central Indonesian Time (WITA), which covers the areas of Bali, South Kalimantan, East Kalimantan, North Kalimantan, Sulawesi, and Nusa Tenggara; and Eastern Indonesia Time (WIT), which covers the Maluku and Papua regions.
It's easy like this: If it is 7 am in Jakarta, then the time in Bali is 8 am, while the time in Jayapura is 9 am.
So it's not surprising that on New Year's Eve, our friends in Papua will celebrate the new year 2 hours earlier than us in Jakarta.
The time difference in the world
You need to know the world that the time used – including us in Indonesia – use the standard Greenwich Mean Time (GMT), centered, or the zero point is at the Greenwich Observatory in London, England.
Jakarta has GMT+7, which means it is 7 hours ahead of Greenwich, London.
Uniquely, it's not like we are on the equator and experience only two seasons: the rainy season and the dry season. Countries that experience four seasons: winter, spring, summer, and autumn, will experience a change in time.