# How would you explain to someone that living in a different time zone doesn't mean you live in the future?

Hypothetically, suppose someone came to you and stated that they have been living in Australia for a while and since it's timezone is ahead by x number of hours, during that time they've been living in the future.

Obviously it's ridiculous, but how would you reason with them that they're wrong?

My reasoning would be that time zones are a human artifact, created due to the rotation of the Earth to ensure that certain points in the day, such as noon happen when the sun is in a certain position in the sky, are the same at all points on Earth (by this I mean that midday is always when the sun is straight overhead, wherever you are on Earth). As such, it cannot have any effect on the physical passage of time.

Importantly, the notion of "present" is the same no matter where you are located on Earth - time passes at the same rate at all points on Earth. An event, such as a flash of lightning, at one point on Earth, occurs "at the same time" for observers located at any point on Earth, it is simply that they have labelled the particular instant in time with different coordinate values (one shifted with respect to the other). The point being that what happens in the present for one observer on Earth, happens in the present for all observers on Earth (it doesn't happen in the past for some, the present for others, and the future for another).

Would this be a reasonable argument?

• "An event, such as a flash of lightning, at one point on Earth, occurs "at the same time" for observers located at any point on Earth," Must. Not. Mention. Relativistic. Effects. Commented Oct 20, 2016 at 19:36
• @dmckee I was neglecting relativistic effects since in most everyday cases they will be negligible - certainly the rate at which time passes will not change for humans at different points on Earth. In any case, is the argument I gave acceptable, or would there be a better way to put it? Commented Oct 20, 2016 at 19:47
• I figure I'm always living in the future, since it keeps arriving whether I like it or not. I am a real time traveler (finding relevant XKCD left up to the reader). Commented Oct 20, 2016 at 19:47
• Also, when the temperature on one side of the Canadian border is zero degrees, the temperature on the other side is 32 degrees, so the United States is a much warmer country. Commented Oct 20, 2016 at 22:34
• Move your watch forward a couple of hours and tell them you are now in the future?
– fqq
Commented Oct 20, 2016 at 23:05