What time is it a mile east of me.

[Limmin]

Oh, my, I’m so late to this thread…

1. OP, you’re basically solving the problem of longitude.

Well actually, you’re solving it backwards, but it takes the same math. There’s a whole lot of books about it, I’d suggest reading “Longitude” by Dava Sobel. Nice little book. Was made into a BBC drama starring Jeremy Irons (!). Also see https://en.wikipedia.org/wiki/Longitude_(book)

The setup: Sailors at sea had always found it pretty easy to find their latitude with a sextant by just measuring the angle between a star (or planet, or even the sun) with the horizon, and your latitude, itself an angle, just pops out directly. Really simple. Notice, latitude just tells you how far north or south you are. But when you’re navigating across the ocean, you really want to know your East-West numbers, and for that you need longitude. To solve for longitude, you need to know the exact time, and (yes) your latitude. And you need to measure angles of objects near your East or West horizons, such as morning or evening start (best measured at twilight, when you can still see the horizon).

So the story Longitude is really about the need to solve the problem, and how it was eventually solved mechanically, but a certain John Harrison, who made (for the time) phenomenally precise clocks. They compensated for different temperatures (which affect properties of the metal movements of the clocks), and had a devices that functioned as pendulums that were not affected by wave motion you feel when on board.

So back to my premise: Saying “what time is it, 1 mile east of me” is kind of equivalent to “20 seconds ago, the sun was at its zenith over me, and the time was 12:00. My latitude is X. So now, where is the sun at its zenith?” Answer: One mile to the East of you.

2. You’re going faster the closer you are to the equator

As stated previously, yes. This is the reason why, for rocket launches we usually choose a launch site that is as close to the equator as possible! So, Florida, Texas, Guiana. Such flights already start moving in the right direction at a higher speed, so they take a little less fuel to reach orbit.

[Limmin]

past 5 minute error corrections…

>> morning or evening STARS not start

>> one mile to the WEST of you (since the sun moves from east to west).

It would be better to rephrase the problem to ask how fast does the sun move per minute at my latitude.
Then, one mile to the East of you it was overhead 20 seconds ago. So if it’s noon here now, it’s 12:00:20, one mile to the East of you.

[RitterSport]

@Grrr

Thanks for the answers guys.

So just to wrap my mind around this. Is a guy sitting at the equator spinning around on the planet faster than a guy siting in Alaska?

You obviously never read enough Calvin & Hobbes:

https://www.reddit.com/r/calvinandhobbes/comments/2bb04g/im_still_trying_to_wrap_my_mind_around_this/

[zimaane]

@bizerta

No, in the northern hemisphere, low pressure areas (e.g. hurricanes) rotate counterclockwise. High pressure systems rotate clockwise.

As for the OP: (A) At the equator, the earth rotates about 1520 feet per second. Elsewhere the speed is 1520 FPS times the cosine of the latitude (e.g. at JFK airport, the speed is 1520 * cos(40.64) = 1153 feet per second. (B) Nit Pick: there is no such time as 12pm. You probably mean 12 noon

You are right, thanks for the correction.

[MarvinKitFox]

@DPRK

The South Pole is on New Zealand time, so you know when to get your breakfast in the cafeteria, and so forth. The sun does not rise and set like you are used to, though.

Now THIS is why I like coming here.
I never knew this little factoid.

It made me dig around a bit, and… Surprise surprise, the North Pole has NO time zone.

How… symmetrical

[dtilque]

The South Pole, actually Amundsen-Scott Base, gets its supplies from NZ. Anyone going to or from the base goes through the same place (Christchurch, NZ). So it makes sense they’d keep the same time. If for some reason they were directly supplied from the US, say Los Angeles, they’d keep the same time as LA.

The North Pole has no base, so there’s no reason it has or needs a time zone. Time zones are for the convenience of humans; the natural world doesn’t need them.

[Mars_Horizon]

@zimaane

Voila, the clockwise motion of a hurricane.

An earlier poster already corrected this, but to clarify, hurricanes spin counterclockwise in the Northern Hemisphere. They spin clockwise in the Southern Hemisphere.

Why Do Hurricanes Spin Differently In The Northern And Southern Hemispheres?

[Quercus]

@DPRK

This has been discussed in various threads. “12 p.m.” may be “cromulent” (??), but when is it? Since nobody really knows for sure- and there is no way the US Government Publications have been consistent on this- it is best to avoid such designations. Having said that, a 12-hour digital clock will switch from “a.m.” To “p.m.” at the moment of noon, so you will see 12:00 pm when you look at it.

I can see the remote possibility of confusion, but it seems to me that a moment’s reflection would make it obvious that it’s clearer and more logical for exactly 12:00 noon to have the same am/pm designation as 12:01 in the afternoon and 12:00:01 (including seconds) and 12:00:00 and 1 millisecond (all of which are clearly pm).

Does anyone seriously advocate that noon should be “12:00 am”?

[burpo_the_wonder_mutt]

If you’re standing 3 feet from–and facing–the North Pole, east is to your right, so 1 mile east is 422 days in the future.

Or, ask Santa Claus.

[DPRK]

@Quercus

Does anyone seriously advocate that noon should be “12:00 am”?

According to the summary table on Wikipedia, the U.S. Government Publishing Office before 2008 (when they abruptly reversed themselves) and after some unspecified point (the 1953 guide recommends simply “noon” or “12 m.”), and officially in Japan, as well as other miscellaneous users.

[DPRK]

“12 p.m.” for noon by no means seems to be a strong consensus either- style guides like Chicago/AP/UK/Canada and NIST all recommend “noon”.

[ftg]

@Grrr

Okay, I know the official time is the same time as me. But if we were to do the math, what time would it be a mile east of me if it were exactly 12pm?

I’m suprised no one has done the usual nitpicky thing of pointing out that it may not be the case that the “official” time is the same a mile east of you.

Thanks to time zones. If you are near the eastern edge of one, it’d be an hour later. Usually.

Plus, there are some places here and there in the US where going east results in an decrease of an hour. For example, there are bits along the Mountain-Pacific time zone boundary in Oregon and Idaho that have this property.