To quote
Slartibartfast, "I've always been a big fan of science."
Of course, growing up a lot of my sources were science fiction, starting with comic books. The problem there is that while those writers would start with a valid scientific idea, they would then extend it beyond reason, since all they needed was something that sounded scientific to support their fanciful story; eg, Stan Lee knowing nothing about gamma rays deciding that it sounds good so he used it in his story, the use of mutations to explain the X-Men, Star Trek TNG constantly playing fast and loose with DNA. Despite their many inaccuracies (to greatly understate the matter), such sources still served the purpose of at least making the reader aware of the existence of such ideas and
very basically what they were
and from there the reader would need to research further. Kind of like Wikipedia should be used, not as a final authority but rather as a starting point in one's research of a subject.
Science popularization (eg,
Popular Science-type magazines, science TV shows, articles in newspapers and popular magazines) is generally better at conveying the science, but that also often fails. "There is no royal road to mathematics" also applies to science, especially to more advanced scientific ideas (but also, sadly, to more basic ideas), but there's no room nor popular appeal in a general news article for the kind of detailed explanation that would be needed. Add to that publishers' click-bait mentality, such that it's the editors, not the writers, who write the headlines, so even if the author does a conscientiously accurate job of writing, the editor will give it a sensational title that can even contradict the conclusions of the article.
Caveat lector! (Let the reader beware!)
According to this article, global warming is affecting Earth's rotation and may cause the addition of the leap second to be delayed from 2026 until 2029:
The Earth's rotation is starting to interfere with time and experts are concerned.
The melting ice caps are responsible. Somehow they're contributing to a decrease in angular momentum of the Earth's liquid core, and due to conservation of momentum that translates into an increase in angular momentum of Earth's solid portion. I would have liked to understand this better, but the article doesn't go into detail, and at one point I think the article mistakenly says "orbit" where it meant "rotation." It was perhaps written in haste or by someone with insufficient background.
This article seems to fit that pattern. I took a quick look and it looks like her reporting is a bit alarmist. Also, she didn't explain her alarm sufficiently.
BTW, I spent the last two decades of my civilian career of
Intelligent Designer (AKA, software engineer) working on a precision time and frequency division product that used GPS as a time reference, which involved working with and understanding leap seconds. And since that forms the basis for a popular creationist claim (ie, their gross exaggeration of the rate at which the earth's rotation is slowing down; see my page,
Earth's Rotation is Slowing), I have researched the matter further.
Our basis for the length of the day is the
mean solar day, an average of the time from high noon to high noon, a value which changes day to day because of the effects of the earth's orbit being elliptical. Any form of timekeeping for the general public would need to be synched up with mean solar time.
Official time is based on atomic clocks, which provide a straight count of seconds;
ie, SI seconds which is 1/86,400 of a mean solar day circa 1900. However, it has been found that the earth's rotation is slowing down at an average rate of
two milliseconds per day per century, such that by 2000 the length of the mean solar day has increased by two milliseconds. That means that in about 18 months, that 2 ms per day discrepancy will through our official
UTC clock off from mean solar time by about a second, we add a
leap second to sync UTC back up with the sun.
While the earth is generally slowing down, the factors causing that include factors that slow it down
as well as factors that speed it up. For example, the slow rebound of the Northern Hemisphere from the removal of the weight of the ice cap of the previous ice age is slowing the earth's rotation due to
conservation of angular momentum. That same conservation of angular momentum causes the earth's spin to speed up when a section of the crust drops lower due to a major earthquake. The rate of earth rotation is constantly monitored by the
The International Earth Rotation and Reference Systems Service (IERS -- formerly the International Earth Rotation Service hence the initials) whose findings are used to the
International Time Bureau (BIH,
Bureau International de l'Heure) to determine when to add
or subtract a leap second -- so far, they have only added leap seconds since the earth is slowing down overall.
Your article seems to be quoting someone as saying that the earth's rotation is speeding up, from which the article is sounding an alarm. But contrary to that article, there's no need for alarm over the adding of a leap second being delayed,
because it has already happened before. After a leap second had been added 31 Dec 1998, the next one had not been added until 31 Dec 2005, a period of
seven years without adding a leap second. Similarly, the last time we added a leap second was on 31 Dec 2016,
seven years ago (plus 30 Jun 2024 has been announced of having no leap second, and what will happen 31 Dec 2024 has not yet been announced).
Nonetheless, having worked close the metal with GPS satellite messages (ICD-GPS-200) and with our own implementation support for leap second changes, preparations have been made to handle the event in which a leap second is
subtracted instead of being added. We (ie, the industry) are well aware of the possibilities so no surprise there and no need for any panic.
POST SCRIPT
Why are we basing our time on what a second was in 1900? Here is my explanation from my page,
Earth's Rotation is Slowing:
quote:
The Second
I heard a story from the late 1800's about an editorial in a magazine -- Scientific American, as I seem to recall -- which stated that we have discovered everything there is to discover and invented everything there is to invent. If that story is true, then that author was incredibly wrong.
It was around that time that astronomers were beginning to suspect that the rate at which the earth rotates is not constant, but rather is slowing down. By 1920, they had confirmed that suspicion. This presented astronomers and physicists with an enormous problem. Time is a factor in most of the equations they work with, so they could not afford to use a unit of time that is based on a time source that is changing; the second must remain constant. Astronomers needed to find some other time base, one that doesn't change.
Astronomers' solution to that problem was ephemeris time, which was arrived at basically by using precise observations to solve for time. In reality, it was more complicated than that as you can read in the Wikipedia article, ΔT ("delta time"). The calculations are based on astronomical observations made between 1750 and 1892, centered around the year 1820. The resultant ephemeris time, accepted as a standard in 1952, was based on an epoch date of 1900 January 0. Therefore, the ephemeris second is the length of a second in 1900, though some sources give 1820 as the base date.
As physicists developed atomic clocks, they used ephemeris time to calibrate them. Thus when the atomic second was defined in 1967 as 9,192,631,770 cycles of the Cesium-133 atom at zero magnetic field, it was the same length as an ephemeris second, which in turn was the same length as a mean solar second in 1900. I think you can see where this is leading us.
When Coordinated Universal Time (UTC) was adopted in 1970, it used atomic time. Hence, one second in UTC is the length of one mean solar second back in 1900 and one day in UTC is equal to 86,400 of those seconds. Since the rate of the slowing of the earth's rotation is about 2 milliseconds per day per century and it has been a little more than a century since 1900, that means that a mean solar day now is about 2 milliseconds longer than a day according to UTC.
BTW, official time is kept by the International Bureau of Time (BIH), the National Institute of Standards and Technology (NIST), and the US Naval Observatory (USNO). One PBS technology series out of Oregon did an episode on time in which they referred to those scientists as "The Time Lords."
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