Flight speed: How fast to notice rapid night/day change?

"Nobody" wrote in message
...
Mxsmanic wrote:
12 PM is noon; 12 AM is midnight.

12:00 is noon. 00:00 is midnight.

The space station goes at about 25,000km/h. They see sunrise and sunset
once per 45 minutes. An aircraft, if it is really lucky with strong
tailwinds, may reach 1000km/h. But to get the effect, it would need to
travel straight east.

Another way to quicken sunset would be to travel north east on december 21
in northern hemisphere (north of 45° latitude).

The northern hemisphere is the half of the planet north of the equator (0°
latitude), NOT just the area north of 45° latitude.
And the southern hemisphere is the half of the planet south of the equator.
Hemi=half.

December 21 is the shortest day in the northern hemisphere, but I don't see
why that makes it the quickest sunset. It should actually be the slowest
one.
The quickest sunrise/sunsets are when the sun is orbiting directly above
you, which on 21st Dec with be along the Tropic of Capricorn, which is about
23° south of the equator. Try visiting a country near the equator (or just
in the tropics) and you will see how much faster sunrise/sunset is there.

And if you go too far north, i.e. north of the Arctic Circle (about 66°
north), on 21st December you won't even get a sunset or sunrise. It'll just
be dark.



--
Posted via a free Usenet account from http://www.teranews.com

"Hatunen" wrote in message
...
Unfortunately, Mixi is wrong. Noon is 12m, "m" being short for
"meridien", which means "noon". It is neither ante- nor post-
meridien and is simply meridien, or the time when the sun crosses
the meridian (which means "noon line").

While you're technically correct, this is one of those rare times
when Mxs also got something right - "12 AM = midnight,
12 PM = noon" IS the convention used in those situations
where the "m" is not used or unavailable (as is the case in
practically all computer-generated times, digital clocks, etc.).

Bob M.

Hatunen writes:

Unfortunately, Mixi is wrong. Noon is 12m, "m" being short for
"meridien", which means "noon". It is neither ante- nor post-
meridien and is simply meridien, or the time when the sun crosses
the meridian (which means "noon line").

Who is using 12m? Anyone who needs to avoid ambiguity is using a 24-hour
clock.

Hatunen wrote:

On Tue, 19 Jun 2007 21:59:53 -0700, NotABushSupporter
wrote:


Mxsmanic wrote:


Newby writes:



Imagine 12 Noon or 12 Midnight! There is no 12 PM or 12 AM.


12 PM is noon; 12 AM is midnight.

Wow, I agree with you, for once.


Unfortunately, Mixi is wrong. Noon is 12m, "m" being short for
"meridien", which means "noon". It is neither ante- nor post-
meridien and is simply meridien, or the time when the sun crosses
the meridian (which means "noon line").

Actually, it has been understood for many years that 12 AM is midnight.

RAK wrote:
The northern hemisphere is the half of the planet north of the equator (0°
latitude), NOT just the area north of 45° latitude.

But at southern latitudes, the changes between winter and summer are not
dramatic.

And while it is true that sun sets faster at equator, this is for fixed
points. When you are travelling, heading for darkness will get you from
daylight to nighttime fastest.

In december, going from Edmonton for instance, you can rather quickly
get to land that is without sun in a couple of hours even of you depart
eary in morning. (note that without sunshine != total darkness.)

If you are between the tropics, the sun is up roughly 12 hours and you
cannot quickly escape from that cycle because you are so far way from
the polar extremes.

Bob Myers wrote:
While you're technically correct, this is one of those rare times
when Mxs also got something right - "12 AM = midnight,
12 PM = noon" IS the convention used in those situations


When using the real clock, it becomes obvious why the above applies:

11:59 is AM. 12:00 is PM.
23:59 is PM. 00:00 is AM.

so noon is PM and midnight is AM.

Nobody wrote:
RAK wrote:

The northern hemisphere is the half of the planet north of the equator
(0° latitude), NOT just the area north of 45° latitude.


But at southern latitudes, the changes between winter and summer are not
dramatic.

Maybe you should clarify that with "southern latitudes of the northern
hemisphere"

"Nobody" wrote in message
...
Bob Myers wrote:
While you're technically correct, this is one of those rare times
when Mxs also got something right - "12 AM = midnight,
12 PM = noon" IS the convention used in those situations


When using the real clock, it becomes obvious why the above applies:

11:59 is AM. 12:00 is PM.
23:59 is PM. 00:00 is AM.

so noon is PM and midnight is AM.
Not so.

PM = Post (meaning after) Meridian
AM= Ante (meaning before) Meridian

Please see the info at the below site:

http://www.worldtimezone.com/wtz-names/wtz-am-pm.html

Newby wrote:

"Nobody" wrote in message
...

Bob Myers wrote:

While you're technically correct, this is one of those rare times
when Mxs also got something right - "12 AM = midnight,
12 PM = noon" IS the convention used in those situations


When using the real clock, it becomes obvious why the above applies:

11:59 is AM. 12:00 is PM.
23:59 is PM. 00:00 is AM.

so noon is PM and midnight is AM.

Not so.

PM = Post (meaning after) Meridian
AM= Ante (meaning before) Meridian

Please see the info at the below site:

http://www.worldtimezone.com/wtz-names/wtz-am-pm.html


What makes this the utmost authority on the subject?
Do you think you could look and find a website that states 12AM is midnight?

Newby wrote:

"Nobody" wrote in message
...

Bob Myers wrote:

While you're technically correct, this is one of those rare times
when Mxs also got something right - "12 AM = midnight,
12 PM = noon" IS the convention used in those situations


When using the real clock, it becomes obvious why the above applies:

11:59 is AM. 12:00 is PM.
23:59 is PM. 00:00 is AM.

so noon is PM and midnight is AM.

Not so.

PM = Post (meaning after) Meridian
AM= Ante (meaning before) Meridian

Please see the info at the below site:

http://www.worldtimezone.com/wtz-names/wtz-am-pm.html


How about the following from Wikipedia, which also indicates the ANSI
standard


However, it has become common practice in the United States to designate
12:00 p.m. as noon and 12:00 a.m. as midnight at the beginning of the
day. This convention is standardized for computer usage in an ANSI
standard.(which extends the international standard ISO 8601 time
notation with a 12-hour a.m./p.m. variant for the U.S.-market).

12 a.m. and 12 p.m. are widely used in the UK, though considered by some
incorrect, as explained in the website of the National Maritime Museum,
Greenwich: