Daylight Saving Time

[PippaB]

Standardized time, probably should have said "standardized local time". All the things that "must" run on schedules could just as easily run on UTC (or epoch, or MS time, or any one of several other "universal" measures of time). In fact, on the back end, nearly all of them do so they don't have to deal with silly things like people shifting clocks back and forth by an hour. Only the tables presented to humans are shown in the local time. Don't confuse time, as a construct used to measure our orbit, as "standardized local time" where we are crammed into shoeboxes that may not fit for the convenience of someone else.

For the 0.06% of humanity that lives in places that have occasional perpetual daylight and darkness, I'm sure they can work something out for themselves.

In the US, Congress has perennially been considering "permanent DST" i.e. changing the definition of the time zones. All of this nonsense so people don't have to change the opening time of their business to match nature. And at the same time remove humans yet further from their connection to nature.

I guess I live a fortunate life. The animals start stirring about half an hour before sunrise, which gets me out of bed about that time. I tend to them, and myself, and then I go to work. I live in the mid latitudes, so in the summer that has me up around 5:30, at this time of year (well a few days ago) it is 6:30-7, then the clocks change and back in the 5 o'clock hour, but the animals never seem to notice that the clock looks different. The fortunate part is that my "day job" accepts that I will show up about an hour after sunrise, work my time, and call it a day. I'm still around for the majority of the "normal hours" for meetings and client interface, but in the summer I get a nice long afternoon - exactly the purported reason for DST.

[GordMay]

Originally Posted by GordMay

...
The whole of the UK, only, spans about 10° of longitude.
...

For comparison:
The Province of Ontario's E➛W extent is about 25° of longitude - roughly 114° 04’ W to 139° 03’ W
Canada’s longitudes extend across about 88° of longitude, from approximately 53°W to 141°W.
Canada has 6 time zones.

[El Pinguino]

Originally Posted by GordMay

England [United Kingdom of Great Britain and Northern Ireland] has only one time zone, Greenwich Mean Time [GMT].
The whole of the UK, only, spans about 10° of longitude.
The planet has 24 time zones, of 15° each [more or less].

And only three countries in the southern hemisphere have more than one, Australia and Indonesia with three and Brazil with two.

China is the outlier in all this, despite spanning 60º of longitude they only have one time effectively based on Beijing. The western bits just have to cope with a very late sunrise.

[GordMay]

Greenwich Mean Time [GMT] is often confused with Coordinated Universal Time [UTC]; but , GMT is a time ZONE, and UTC is a time STANDARD, that is used to keep time synchronized, across the world.
However, they share the same current time, in practice.

Neither UTC nor GMT ever change for Daylight Saving Time (DST).
However, some of the countries that use GMT switch to different time zones during their DST period.
For example, the United Kingdom is not on GMT all year, it uses British Summer Time (BST), which is one hour ahead of GMT, during the summer months.

Coordinated Universal Time [UTC] gets one leap second added, every 19 months, to reflect that the Earth slows down its rotation.

Some EXCELLENT information, relevant to the discussion of time, from the International Earth Rotation Service [IERS]

Time ➥ https://www.iers.org/IERS/EN/Service...time_node.html

Earth Rotation ➥ https://www.iers.org/IERS/EN/Service...arth_node.html

Glossary ➥ https://www.iers.org/IERS/EN/Service...sary_node.html

[Montanan]

How Trick or Treating changed Daylight Saving Time:

Up until about two decades ago, daylight saving time ended the last Sunday in October rather than the first Sunday in November, as it does now. That would make sunset an hour earlier, meaning less daylight for kids to go door-to-door.


How sweet is that!

[GordMay]

In modern times, clocks underpin everything people do, from work, to school, to sleep. Timekeeping is also the invisible structure that makes modern infrastructure, like computers, GPS, & etc, work.

The ancient Egyptians invented the first water clocks, and sundials, more than 3,500 years ago [±1500BCE?].
Before that, people likely tracked time with devices, that did not survive, in the archaeological record. Perhaps they used an upright stick, in the dirt, that acted as a primitive sundial; or no device at all, perhaps by observing the location of the sunrise, and the sunset, each day, and by watching how high the sun reaches in the sky, or observing the transit, of stars, at night.

And, for measuring discrete units of time, they used water clocks, which have been found, in Egypt, and Babylon, dated to [around] 1500 BCE.
In China, historical records claim that water clocks [‘louke’] were invented, by the Yellow Emperor, or Huangdi, a half-historical, half-mythical figure, said to have lived between 2717, and 2599 BCE. The unit “ke” divided the day into 100 equal segments, from midnight to midnight.
Water would eventually lead to some extremely sophisticated timekeeping: by the early 700s CE, Tang Dynasty monks developed a mechanical clock, powered by a water wheel.

We’ve been temporal creatures, living under the tyranny of the clock, for far longer than the industrial age - although not always happily.
After the Romans installed their first public sundial, in 263 BCE, the Roman playwright, Plautus, objected to the new fad of timekeeping, via a character, in one of his plays:
“The gods damn that man who first discovered the hours, and—yes—who first set up a sundial here, who’s smashed the day into bits for poor me!
You know, when I was a boy, my stomach was the only sundial, by far the best and truest compared to all of these....
But now what there is, isn’t eaten unless the sun says so.
In fact, town’s so stuffed with sundials that most people crawl along, shrivelled up with hunger.”

[GordMay]

The Winter solstice, occurs twice yearly, once in each hemisphere, when either of Earth's poles reaches its maximum tilt away from the Sun [when the Sun is at its lowest daily maximum elevation], and is the day [winter solstice] with the shortest period of daylight, and longest night of the year*.

Solar Winter, typically, lasts about 3 months - 45 days, on either side, of the winter solstice.

This year, the DECEMBER* SOLSTICE occurs on Saturday, December 21, 2024, at 4:19 a.m. Eastern time [0920 UTC].
* Northern Hemisphere winter solstice, and Southern Hemisphere summer solstice, when the Sun is directly above the Tropic of Capricorn, in the Southern Hemisphere.

This effect is greatest, in locations that are farther away from the equator. In tropical areas, the shortest day is just a little shorter than 12 hours; in the temperate zone, it is significantly shorter; and places within the Arctic Circle experience polar night, when the Sun does not rise at all.

* Conversely, the day of the December solstice is the longest day of the year, in the Southern Hemisphere. Here, too, the effect is greater the farther a location is away from the equator.
Places within the Antarctic Circle experience Midnight Sun, when the Sun does not set at night.

Earth is tilted, at an angle of about 23.4°, in relation to the ecliptic, as it orbits the Sun, which is why equinoxes and solstices happen.

[GordMay]

Australian scientists have found evidence that time ran slower in the past.

Scientists have confirmed that just 1.5 billion years after the Big Bang [13.8 billion years ago], time ran five times slower, than it does today.

Though scientists have long been aware that conditions just after Big Bang were radically different, than those in the cosmos we see around us today, the discovery shows that time is relative, in regards to the age of the Universe, too, just like Einstein predicted.

The breakthrough is detailed in a 2013 paper [1], published in Nature Astronomy, authored by Geraint Lewis, an astrophysicist at the Sydney Institute for Astronomy at the University of Sydney, and Brendon Brewer from the University of Auckland’s Department of Statistics, who made the long-awaited observation of cosmological time dilation in the early Universe.

Time dilation, has been confirmed many times around Earth. For instance, the global positioning system (GPS) technology, we rely on for navigation, wouldn’t work, if the satellites they use, didn’t have clocks that account for the fact that time runs more slowly at the surface of Earth, than it does at their position in orbit. The time difference is minor, but would quickly accumulate, eventually rendering GPS useless.

More about ➥ https://www.advancedsciencenews.com/...ein-predicted/

[1]“Detection of the cosmological time dilation of high-redshift quasars” ~ By Geraint F. Lewis & Brendon J. Brewer
➥ https://www.nature.com/articles/s41550-023-02029-2

[Uricanejack]

Last year for no particular reason. I went up to the Arctic Circle for 21st June. I didn't actually make it. I decided 10 miles short at Eagle Plains was close enough.
I didn't actually bother to figure everything out ahead of time. Time wise. and booked the only hotel 6 months ahead of time. So I got there on the 21st and figured out i would be watching the sun not set on the 22nd.

F ing DST.

To add to the confusion,
WTH would you use DST when the sun doesn't set.
Even more confusing White Horse is 135 W Longitude ie 9hrs behind GMT and the Yukon doesn't use DST. Yukon uses Yukon Standard Time GMT -7 year round.

Vancouver BC is about 120 W longitude Ie or 8hrs behind GMT and does use DST 7hrs behind GMT for the summer.
Along with Washington Oregon and California.

So BC DST is the same as Yukon Standard Time from March until November even though the Yukon is roughly 15 deg further west.

So for the sunset on the Arctic Circle near Eagle Plains on the 21st of June was at about 0200 on the day I showed up to see it at about 2000.
So I got to watch the sun not set on the 22nd of June at about 0200 local standard time

Or Midnight LMT 21/22 June 2023.

Eagle Plains is 10 miles S of the Arctic Circle. Due to Height of Eye Parallax refraction ect. The Sun was still quite well above the Horizon all night. Even if I was in the wrong place at the wrong time. It was kind of cool.
I continued up to Inuvik and Tuktoyaktuk.
Which of course has nothing to do with sailing other than I went for a paddle in the Arctic Ocean.

Of course now BC has just gone back to PST or Pacific standard time 8 hrs behind GMT

The Yukon Doesn't Change and is still GMT -7.
Which leaves me wondering WTH the Yukon is still on 2hrs ahead of its local time. All winter.
I guess it doesn't matter if there is no Daylight.

According to google. Sunrise Dec 21 Eagle Plains will be at 1254 it will be on the Meridian at 1405 and will set at 1517. If anyone is interested.

The other Place you can get to the Arctic Circle is Just North of Coldfoot Alaska. I don't know what they do for time.

Chatting with the locals about how weird constant daylight was. I also asked about constant night. They told me spring was their favorite time of year because the sun comes back.

[Uricanejack]

Just thought Id look up Montana for the heck of it.
I live in BC at around 123 deg west Pacific time GMT -8 DST GMT -7
3 deg west of The mean longitude of 120 for my time zone GMT -8

Montana is Mountain time same as Eastern BC and Alberta. and a bunch of other States.
The Mean Long for GMT -7 is 105 deg west. Or Mountain time.

Helena, I stopped for a burger once. Is about 112 deg west. So winter time in Western Montana is a little bit more than 0.5 hr behind local mean time.
Which is ball park real time. For most standard time zone.
France should be on the same time as the UK LMT but is 1 hr ahead to be the same as Most of western Europe So sunrise in France is 1hr later standard time than it does according to standard time in the UK.

[GordMay]

Spanning about 57.5° of longitude, Alaska would naturally fall into four time zones, but, political and logistical considerations have led to the use of two time zones - Alaska Standard Time [AKST = UTC - 9]], and Hawaii–Aleutian Time west of 169° 30' W [HST = UTC - 10].
Alaska, and the Alaskan portion of the Hawaiian zone observes daylight saving time [HDT, UTC−09:00], while Hawaii [itself] stays on standard time.

[GordMay]

NASA is creating a lunar time zone: Coordinated Lunar Time [LTC]
The White House Office of Science and Technology Policy has directed NASA to establish a unified standard of time, for the moon, and other celestial bodies, by the end of 2026.
The new lunar time zone will be known as "Coordinated Lunar Time", or LTC.
The moon is smaller than the Earth, and its gravity is weaker; which is why, on the lunar surface, a single Earth day would be roughly 56 microseconds shorter than on our home planet, and although a tiny number, it would lead to significant inconsistencies over time.
Unlike Earth, the moon doesn’t have a consistent 24 hour cycle, of daylight, and darkened nights. On the moon, the equator receives roughly 14 days of sunlight, followed by 14 days of darkness; and in the polar regions, there’s permanently lit, and permanently shadowed areas.
The new time scale would underpin an entire lunar network, which NASA and its allies have dubbed 'LunaNet'.

NASA to Develop Lunar Time Standard for Exploration Initiatives
➥ https://www.nasa.gov/solar-system/mo...n-initiatives/

[massnspace]

Originally Posted by GordMay

NASA is creating a lunar time zone: Coordinated Lunar Time [LTC]
The White House Office of Science and Technology Policy has directed NASA to establish a unified standard of time, for the moon, and other celestial bodies, by the end of 2026.
The new lunar time zone will be known as "Coordinated Lunar Time", or LTC.
The moon is smaller than the Earth, and its gravity is weaker; which is why, on the lunar surface, a single Earth day would be roughly 56 microseconds shorter than on our home planet, and although a tiny number, it would lead to significant inconsistencies over time.
Unlike Earth, the moon doesn’t have a consistent 24 hour cycle, of daylight, and darkened nights. On the moon, the equator receives roughly 14 days of sunlight, followed by 14 days of darkness; and in the polar regions, there’s permanently lit, and permanently shadowed areas.
The new time scale would underpin an entire lunar network, which NASA and its allies have dubbed 'LunaNet'.

NASA to Develop Lunar Time Standard for Exploration Initiatives
➥ https://www.nasa.gov/solar-system/mo...n-initiatives/

What does “lunar time zone” have to do with sailing???

[GordMay]

Originally Posted by massnspace

What does “lunar time zone” have to do with sailing???

You’re beginning to remind me of the Roman Censor Marcus Porcius Cato [who had fought against Carthage in the 2ND Punic War], who popularised the phrase "Delenda est Carthago" ['Carthage Must be Destroyed!']. Accounts [by Plutarch] describe Cato [the Elder] finishing every speech he gave with this sentence, no matter what his speech had been about.
Relevance: Cato was also known to remind the Roman Senate that Carthage was only a three day sail away from Rome.

[massnspace]

Originally Posted by GordMay

You’re beginning to remind me of the Roman Censor Marcus Porcius Cato [who had fought against Carthage in the 2ND Punic War], who popularised the phrase "Delenda est Carthago" ['Carthage Must be Destroyed!']. Accounts [by Plutarch] describe Cato [the Elder] finishing every speech he gave with this sentence, no matter what his speech had been about.
Relevance: Cato was also known to remind the Roman Senate that Carthage was only a three day sail away from Rome.

Instead of gaslighting with parallels to Roman mythology, why dont you directly answer my question?

Posed again: What does “lunar time zonne” have to do with sailing?