Greenwich mean time & NYE, can someone please explain?

[TulipDaisy]

I know I'm a bit of a thickie but can someone please explain how it is that I've just read in the news that Hong Kong and Australia have already had their NYE when the Greenwich meridian is in the UK? I thought because we have the zero line, we'd be the first to go into 2019. Why is this not the case - who gets to go first & why? Also, who goes last?

Why is the date line different to GMT?

Wow, thanks for all the input, this has been truly enlightening! My next question was going to be 'So who decided that the dateline should be there rather than anywhere else?' -but Dr Google answered that one! This has been fab. Thank you all. I missed out of so much schooling-wise.

Happy New Year, Ginger!

Google railway time as well OP. We didn't have 'standard times'. It's interesting.

I've just answered my own and OP's question about the date line with this from timeanddate.com:

Drawn up in 1884

The 180° meridian was selected as the International Date Line because it mostly runs through the sparsely populated Central Pacific Ocean. It was decided at the International Meridian Conference in 1884 in Washington, D.C. where 26 countries attended.

That means that for the first time there are now people in Australia who are legally adults who were born in the 21st century.

The first adults not born in the last millennium! In a few hours, it will happen in the UK too...

GMT or UTC is "zero" as you say, and other countries define their timezones in terms of how far ahead or behind GMT they are. The furthest ahead will celebrate New Year first and the furthest behind last.

The place furthest ahead of GMT is the Line Islands in Kiribati in the Pacific, at GMT+14. The furthest behind are some uninhabited American islands, also in the Pacific, at GMT-12.

The "International Date Line" isn't defined by a single organization really. It's just the dividing line between the areas that are many hours ahead of GMT and those that are many hours behind. When countries near the dateline change their timezones, it can change the dateline, as Kiribati did in 1995 and Samoa did in 2011.

And just to confuse things further: major natural events - earthquakes, big storms, etc - are usually designated by GMT/UTC/Z(Zulu) time, not local time. So an event on the east coast of the USA that happened at 1 p.m. local time, would be timed as 18:00Z. Or something that happened on the west coast of the USA at 5 a.m. Pacific Daylight Time, would be timed as 12:00Z.

Hurts my brain! But scientists are used to doing the mental gymnastics involved, because it means that everyone in the international scientific community are all working to a single time baseline. And means that someone in, say, Australia, doesn't have to compensate for daylight saving time in, say, America.

You asked a good question, by the way, so don't feel bad that you didn't know. Not everyone will have picked up the time zone stuff at school, and many who did will probably have forgotten about it. I admit that if I ever did know about it previously, I'd forgotten it, until I started reading up on some science stuff.