Of clocks and time changes
The clocks having gone forward in the early hours of this morning, my phones and computers have automatically adjusted but I had to spend a bit of time manually adjusting all the clocks in my home.
Ironically, the ones which caused the most difficulty are the ones which should not have needed any manual adjustment as they are supposedly radio controlled.
As always happens at the equinox when clocks go forward in the spring or back in the autumn, there ha been a fair amount of debate this weekend on social media about whether changing between time systems like "Greenwich Mean Time" and "British Summer Time" makes any sense.
Sometimes these arguments are based on the practical issue of whether the change is actually convenient or helpful. All time zone systems being artificial intellectual constructs which inevitably contain compromises, such arguments are equally inevitable and may well make perfect sense.
Some arguments, however, are based on the idea that changing the time system is in some way "falsifying the clocks." Such arguments are almost always nonsense and the people who deploy them remind me of the saying about King James the Sixth and First being "the wisest fool in Christendom. Sometimes very clever people waste their own time and that of others by diving down intellectual rabbit-holes.
On any planet such as Earth which combines rotation about its' own axis while orbiting around a light-source such as a star, there will be a sunrise and sunset on all days over most of the planet, except for areas at the poles which may experience sunlight for the whole day for part of the summer and darkness during the whole day for part of the winter if the axis of rotation is not perpendicular to the plane of the planet's orbit.
The time of sunrise and sunset, and the length of time between them, does have an objective reality. But on planets like the Earth where the axis of rotation is significantly tilted from a position perpendicular to the planet's orbit plane, (in Earth's case this axial tilt is a significant 23.44 degrees,) that objective reality will shift slightly every day, changing annually in a cycle from the summer solstice in the Northern Hemisphere which at that time is tilted towards the sun, experiencing days of the maximum length and summer, to the winter solstice, when the Northern hemisphere is tilted precisely away from the sun, experiencing the shortest period of sunlight, or none at all in the Arctic Circle around the North Pole and winter.
The seasons are, of course, reversed in the Southern hemisphere, where the Summer Solstice coincides with the North's Winter Solstice and vice versa.
The time of sunrise and sunset also shift whenever you move to a different location on the planet's surface: move away from the equator and the seasonal variance becomes greater, with longer days n summer and shorter ones in winter. Move in the direction of the planet's spin (east) and the duration of the day stays the same but both sunrise and sunset are earlier.
Move west against the spin and both will take place later.
So while sunrise, sunset, and the point when the sun is highest in the sky all have objective reality these all vary according to where on the planet you are and from day to day.
Intelligent creatures like humans construct intellectual systems to measure and manage time. For obvious reasons, these are invariably related to the objective reality of important factors in the daily cycle of light and heat, such as sunrise and sunset but - and here is the key point - these intellectual systems invariably involve compromises because it is not possible to get them to match exactly.
So, for example, "Greenwich mean time" is a system defined as having 24 hours, with noon t the average time when it is noon at Greenwich (or anywhere along the meridian line of longitude which the Greenwich Observatory in London sits on.)
If you are to the east of the Greenwich meridian, you get sunrise, noon, and sunset a bit earlier than someone at the same latitude but on that meridian does. And if you're to the west but the same distance north or south of the equator, you get them all a bit later.
But it would render communicating with each other about time practically impossible if humans on earth used an infinite number of time zones, each person defining noon as being equal to true solar noon for the exact spot where he or she happened to be located. Instead the earth has been divided into a number of time zones. The original plan was to divide the planet into 24 time zones, from 12 hours ahead of Greenwich to 11 hours behind. People being people, we eventually ended up with 37 different time zones because some countries wanted to use zones which differed by half-hour periods, while other countries wanted a common time over a larger area.
I have now referred to Greenwich seven times so far in in this essay, and there will be several more to come. That's because British astronomers and navigators did what was then cutting edge work on this from the establishment of Greenwich Observatory in 1670 onwards, leading to the adoption of Greenwich Mean Time (GMT) as an common standard in Britain from the mid 1800's for railway timetables, which obviously needed such a common standard, then by act of parliament as the standard time in Britain, in 1880.
Following this, in October 1884, the International Meridian Conference formally established the Greenwich meridian as the Prime Meridian for international longitude and GMT which would be used, with offsets, as the basis for global time zones.
On January 1, 1972: GMT was largely superseded as the international standard by Coordinated Universal Time (which is abbreviated as UTC), based on atomic time. You could write a PHD thesis on how UTC differs from GMT, by varying amounts up to 0.9 of one second.
Putting the clocks forward in summer was first adopted by both sides during World War One - and was so associated with that conflict that it was known informally as "War Time."
It was originally used by wartime governments to get people to do things at a more optimum time - basically to get up earlier to take advantage of early morning daylight in the summer. The strategic purpose being to save coal but it was also sold to people as "daylight saving."
Since 1916 many countries have made bi-annual adjustments to their clocks. But some countries which used to do this have stopped.
Ever since World War One there have been arguments in countries which adjust their clocks about whether it would be better to stick to one time and standardise it, and if so which time to standardise on.
There has been a deadlock in the EU Council of ministers for nearly a decade on this subject, after the European Parliament voted in 2019 to end the practice of bi-annual time changes. The Council of Ministers has been unable to agree on whether to permanently adopt summer time or winter time.
Although 84% of Europeans who responded favored ending the clock change in a 2018 consultation, the initiative has stalled for years, with debates in 2025 seeking to address the hurdles holding up the legislation.
Proponents of ending the change, such as the government of Spain, argue that the biannual switch offers minimal energy savings and negatively impacts health, economy, and wellbeing.
Scientific evidence often favors maintaining standard time (winter time) as it is closer to natural solar time, but some sectors of the European economy prefer the long evenings offered by getting people up earlier using so-called daylight saving time (the current summer time).
In the absence of any agreement the current system of changing clocks on the last Sunday of March and October remains in place for now.
Britain had a similar debate in the 1990s, with the most emotive and memorable arguments focussing particularly on safety for groups like farm workers and on road safety for children travelling to school. These were deployed particularly effectively by opponents of an idea then being floated of moving permanently to Summer Time. This warned the government and opposition parties alike that they might be stirring up a hornets' nest if they moved away from the status quo.
There was a total absence of consensus and the political parties just quietly dropped the issue. Twice a year there has been a spat about it on Twitter, now X, and then the issue goes away for another six months.
Since, as we have seen, the time zones which countries adopt are a compromise, it is not in the least surprising that some people will have practical arguments, many of which make sense, for a different compromise, and other people will have equally practical arguments, many of which also make sense, against those proposed changes.
However, there is an ideological argument which some people are deploying, which IMHO does not make any sense, for what might be called a "purist" approach to time zones from people who dismiss any arrangement in which 12 noon isn't as close as possible to the average time the sun reaches its highest point in the sky as "falsifying the clocks."
Let me try to explain why I don't agree with this argument. I have already explained that the time systems we use are an intellectual construct which represent a whole system of compromises.
The objective reality of sunrise, noon and sunset which we try to capture with that construct does not just vary through the year and as you travel: it is less consistent than people might think.
Earth's orbit is not a perfect circle: it is elliptical and the speed with which Earth orbits the sun can very significantly through the orbital cycle (or "Year.")
For this reason, the actual time at which the sun crosses the meridian even in the same spot can vary by up to 16 minutes. An accurate sundial showing true solar time can be up to 16 minutes behind an accurate clock or 14 minutes ahead, depending on the season. That word "Mean" in the name "Greenwich mean time" refers to the fact that this time is an AVERAGE, not a constant.
So I would ask anyone who thinks that changing from Greenwich Mean Time to British Summer Time in the summer, or any similar change, is "falsifying the clock" whether they think someone who lives in Plymouth who uses GMT rather than true local time is also "falsifying their clock."
Because, although the sun does not always cross the meridian at Greenwich at exactly 12 noon GMT, it always does so on a given day about ten minutes before it crosses the meridian as seen from Bristol and about sixteen and half minutes before it does so as seen from Plymouth.
The railway companies adopted GMT throughout Britain in the mid 19th century, not because they were silly enough to imagine that it is a perfect representation of time in every part of the UK, but because they needed some sort of consistent time standard to make railway timetables make sense. One would hope that the UK parliament also understood this when they passed the 1880 act which made using GMT as a standard time system the law throughout Britain.
Neither GMT nor it's successor as an international, UTC, is some sort of absolute truth, they are convenient approximations to true time which help us to manage our lives, from running railways and navigating ships and planes to computer protocols.
I'm taking no position on whether using one set of time zones all year round, using a different one moved an hour forward, or switching between them is the optimal solution. You should look at the practical advantages of each.
But to suggest that any of these positions is going to be a precise representation of reality, and the others are "falsifying the clocks," is in my humble opinion, really rather silly.
A longer version of this post with some Sci-Fi references can be found at:
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