[jmartin]

If if fly from east to west and cross time zones the time will change say from 2am to 1 am to midnight. It would seem as though I should run into yesterday but instead I run into tomorrow. How come?

[ebaines]

You do run into yesterday. If it's 2:30 am in NY at that same time it's 11:30 PM the previous day in LA, so if you travel fast enough you can indeed go from today to yesterday.

Perhaps you are thinking about the International Date Line - when you cross it flying from east to west you do indeed go forward a day. This has to be so, otherwise if you flew all the way around the world you would arrive back where you started the day before you left! The International dayte Line prevents that from happening - when you fly around the world you cross 24 time zones, for a total of 24 hours you would set your clock back, plus the International Date Line which adds 24 hours, so you come out whole.

There once was a young lady named Bright,
Who could travel faster than light.
She set off one day,
in a relative way,
And returned the previous night!

[Credendovidis]

How fast does an airplane fly? And how much time does it take to fly across one time zone?
At the equator the circumference of the earth is 40.000 km and that equals 24 time zones.
So one timezone is 40.000/24 km = 1.667 km.
A passenger jet plane flies on average 900 km/hour.
So it takes 1.667 km/900 = 1,852 hours= 111 minutes to pass one timezone.
Now : on higher or lower latitudes it take less time as the circumference of the earth there is less, but in most cases it always is more than one hour flying time. And you only gain one hour per time zone .

So yes : you gain 1 hour time per timezone you pass.
But also : you loose more than 1 hour to pass one timezone.
So in effect you always loose time going into any direction, even going west.
Therefore your total time gain is negative, and you will arrive "tomorrow."

Only in very fast planes like fighter jets you can fly over a timezone in less than 1 hour, and than you could arrive before you left, i.e. into the past. (Well : at least in hours, and only when you do not pass the date line).

Good luck to you !

:)

[ebaines]

So yes : you gain 1 hour time per timezone you pass.
But also : you loose more than 1 hour to pass one timezone.
So in effect you always loose time going into any direction, even going west.
Therefore your total time gain is negative, and you will arrive "tomorrow."

Actually all you need do is stand just on the east side of a time zone line, and after midnight take a step to the west across the time zone, and you end up in the previous day. No supersonic plane required. All you need do is move about two feet in under an hour. This gets real interesting in places like the state of Indiana, where some municipalities have adopted daylight savings time and others have not - consequently there are hour differences between adjacent municipalities. It's possible to take a fairly short drive that starts on Tuesday, crosses into Monday, and then continue back into Tuesday again!