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

"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.

Locally observed Noon is neither, simply the instant in which the observed
sun without pausing to don evening clothes, reaches its highest
point/altitude above the horizon. For seafaring lads in the days before
chronometers, locally observed Noon was of some import, for 12 O'Clock
reports could not be rendered unto the Captain before its observation, and
his permission to strike the bell eight on time, declaring it Noon, could
not be given.

Sailors used to worry little over time zones, but forever have noticed Noon
(and used those nice Noon sunlines to establish longitude in modern
chronometer times, more effective than observing the transit of the Moons of
Venus).

TMO

On Jun 18, 9:39 pm, Mxsmanic wrote:

This requires a speed of thousands of miles per hour, beyond what any
commercial aircraft could do.

If an aircraft could go this fast, would those on-board need any
special suit to protect themselves from the effects of the high speed?

Also, would the nose of the plane get too hot?

If you want scary, a total solar eclipse works very well for that.

Scary indeed. But not as much as my solar nightmare -- which involves
the sun suddenly ceasing its existence. Suddenly everything gets dark
and anyone with psyche -- such as humans and other mammals -- would
die from a lethal psychogenic shock [a fatal drop in blood pressure]
caused by the extreme fear and psychological dissociation that would
result from the day rapidly turning into night.

We instinctively fear any sudden dimming of light.

In message "Newby"
wrote:

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

Sure, and at 12:00:00.000 (noon|midnight) that might be true. For
practical purposes, we can have 12:00am and 12:00pm, since there isn't
enough resolution to know the actual time.

That, or for human interaction it's easier to specify AM or PM even if
not entirely technically accurate.

--
If quitters never win, and winners never quit,
what fool came up with, "Quit while you're ahead"?

On Wed, 20 Jun 2007 17:19:20 -0400, Nobody
wrote:

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.

How can noon be PM when PM is the abbreviation for "post
meridien", which means AFTER noon?

It does seem to have become something of a convention, but the
whole thing begs for the use of 24-hour time.

--
************* DAVE HATUNEN ) *************
* Tucson Arizona, out where the cacti grow *
* My typos & mispellings are intentional copyright traps *

On Wed, 20 Jun 2007 23:19:22 -0500, "TMOliver"
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.

Locally observed Noon is neither, simply the instant in which the observed
sun without pausing to don evening clothes, reaches its highest
point/altitude above the horizon. For seafaring lads in the days before
chronometers, locally observed Noon was of some import, for 12 O'Clock
reports could not be rendered unto the Captain before its observation, and
his permission to strike the bell eight on time, declaring it Noon, could
not be given.

Sailors used to worry little over time zones, but forever have noticed Noon
(and used those nice Noon sunlines to establish longitude in modern
chronometer times, more effective than observing the transit of the Moons of
Venus).

Since there were not such things as time zones until the latter
19th century, those early sailors couldn't have worried about
them.

--
************* DAVE HATUNEN ) *************
* Tucson Arizona, out where the cacti grow *
* My typos & mispellings are intentional copyright traps *

Hatunen wrote:
On Wed, 20 Jun 2007 17:19:20 -0400, Nobody
wrote:


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.


How can noon be PM when PM is the abbreviation for "post
meridien", which means AFTER noon?

No, it means after the sun has reached the meridian.
We don't observe local noon today, so why harp on the fact that
12:00:00.00 isn't technically PM, but 12:00:00.01 is.


It does seem to have become something of a convention, but the
whole thing begs for the use of 24-hour time.


Why do we even need timezones?
We could all go to 24 hour time, and on one timezone.
Not everyone works 9-5 anyway.
When it is 0900-1700 on the East Coast, It can be 0900-1700 on the west
coast, and people there could work 1200-2000.

Radium wrote:

: How fast would an airplane need to fly in order to those onboard to
: notice changes in darkness/brightness of the sky -- in which the
: changes in intensity are significant enough to be noticed in seconds?
: E.g. if you are flying towards the darker side of the earth, you'll
: notice the sky getting darker each second just by looking outside.
: Pretty scary!
:
: Earth rotates around the sun at 1,000 MPH, so the plane would need to
: be flying much faster than 1KMPH. Concord planes reached around 1KMPH.

Unless you are at the day-night boundary, nothing is going to change
fast. If you are at the boundary, you don't have to move at all: just
stand around and the light will change.

Said differently: There are only 4 time zones in the US. This mans it
could be 11AM - 3PM on the entire continent, with no darkness to be
seen anywhere.

"Hatunen" wrote in message
...
On Wed, 20 Jun 2007 23:19:22 -0500, "TMOliver"
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.

Locally observed Noon is neither, simply the instant in which the observed
sun without pausing to don evening clothes, reaches its highest
point/altitude above the horizon. For seafaring lads in the days before
chronometers, locally observed Noon was of some import, for 12 O'Clock
reports could not be rendered unto the Captain before its observation, and
his permission to strike the bell eight on time, declaring it Noon, could
not be given.

Sailors used to worry little over time zones, but forever have noticed
Noon
(and used those nice Noon sunlines to establish longitude in modern
chronometer times, more effective than observing the transit of the Moons
of
Venus).

Since there were not such things as time zones until the latter
19th century, those early sailors couldn't have worried about
them.

.....Ahhh, another failed attempt at irony, destroyed by an unwitting
pragmatist.

You and I know that Dave, and some others, but realize among the readers
here are a few convinced that times zones were intelligently designed if not
divinely mandated, and that King James's discovery that Jesus had written in
English is significant history...

Bishop Usher is alive and well, sharing an apartment with Mxsmanic....

TMO

Hatunen wrote:

On Wed, 20 Jun 2007 17:19:20 -0400, Nobody
wrote:


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.


How can noon be PM when PM is the abbreviation for "post
meridien", which means AFTER noon?

It does seem to have become something of a convention, but the
whole thing begs for the use of 24-hour time.


I suppose that it makes as much sense as am would. In a sensible world
12 am and 12 pm would be the same.

On Wed, 20 Jun 2007 23:40:03 -0700, NotABushSupporter
wrote:

Hatunen wrote:
On Wed, 20 Jun 2007 17:19:20 -0400, Nobody
wrote:


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.


How can noon be PM when PM is the abbreviation for "post
meridien", which means AFTER noon?

No, it means after the sun has reached the meridian.

Well, duh. That's the defintion of local noon.

We don't observe local noon today, so why harp on the fact that
12:00:00.00 isn't technically PM, but 12:00:00.01 is.


It does seem to have become something of a convention, but the
whole thing begs for the use of 24-hour time.


Why do we even need timezones?
We could all go to 24 hour time, and on one timezone.

Like China.

Not everyone works 9-5 anyway.
When it is 0900-1700 on the East Coast, It can be 0900-1700 on the west
coast, and people there could work 1200-2000.

We could. We don't want to.

--
************* DAVE HATUNEN ) *************
* Tucson Arizona, out where the cacti grow *
* My typos & mispellings are intentional copyright traps *