In time-zones, where does the new day begin and end?

Question

I'm in the UK, and I know parts of Australia are 9 hours ahead, and parts of America are 9 hours behind.
Is there a line somewhere that if you cross it you go back a day?

Answer 1

You'll want to read about the International Date Line:
http://wwp.greenwichmeridian.com/date-line.htm

Hope that helps!

Answer 2

Not back a day, there are lines you cross that either advance you an hour or send you back an hour......I live in NW Indiana (small corner of the state) and the rest of the state is on a different time zone, so it gets confusing sometimes in the immediate area.

Answer 3

The division line runs down the middle of the pacific, in a somewhat jagged line.

http://www.worldtimezone.com/