As I write this soon-to-be-anachronistic piece, it is already the “new year” in various places around the world. For instance, in Hong Kong it is 12:04 A.M on Sunday while it is only 11:04 AM Saturday here (east coast U.S. time).
The truth is far more complicated and far more interesting to consider.
First of all, there is the notion of sidereal time—time relative to a fixed star‘s position. It is used by astronomers, who cannot rely on our own sun’s position as our positional relationship to it is not fixed. As a matter of fact, starting in the 19th century it was noticed that the “fixed stars” are not fixed either. They are just distant enough that they are far more fixed than our local star seems to be. All sorts of calculations can be sorted out to use a non-fixed distant star or bright astronomical object as relatively fixed, but I neither understand these calculations nor would you (I suspect) find them particularly interesting. So, the bottom line is sidereal time is in constant change here on earth. If I am standing shoulder-to-shoulder with you, we are in different sidereal times. Sidereal time has no respect for time zones. Time zones are useful in that it would be a nightmare to discuss the time it actually is if we were not to bunch time together in chunks like we do.
Second, time is not really measured in chunks like hours, minutes, and seconds. One really has to consider the fastest event in the universe to consider time more accurately, if not more usefully. The shortest time is the calculated Planck time, which is 5.39×10-44 seconds (in other words there are 1.9×1043 tP in one second—roughly 2 followed by 43 “zeros”—an incomprehensibly large number of events on the “standard human time scale (SHTS).” It is the amount of time it takes for a photon in a vacuum to pass through a Planck length, which is also very brief, distance-wise.
The thing about Planck time is that it is a time derived from a physical standard calculated by Planck, so although useful for physicists, there’s something a little incestuous about the whole business. Various elements have layers of electrons probabilistically scooting around their nuclei at mind-bending rates of speed, while also changing their quantum energy levels from their lowest energy levels (aka ground states) to a variety of higher energy levels. These electronic transitions have been studied and are variously known to behave themselves in very dutiful ways. As they are in constant motion between energy levels and motion takes time, even on the atomic scale, the distances and times are very tiny. Cesium atoms, for instance, experiences 9,192,631,770(±some variation) transitions between energy levels per second. The atomic clocks based on this cesium transition are so accurate that they are calculated to lose only 1 second in 100,000,000 years (one hundred million years!) or so.
Part of the work that scientists do is involved in never being satisfied with a “good enough” answer; they are always looking for increased, accuracy, precision, measurement stability, always looking for a more refined “truth” than that which has been understood before. If you were a professional runner, for instance, and you just achieved a personal best, you would not go home, pop open a bucket of ice cream and settle in for the rest of your life. The next time you ran, you would try to better your personal best. Same with scientists, except the standards are set by nature and the tools we have to achieve better outcomes are constantly in the process of improvement.
Cesium has been the standard for measuring seconds for some years now but has just been displaced from its throne by an ytterbium-based atomic clock that “ticks” 518,000,000,000,000 (518 trillion) atomic events per human second. This allows a crazy level of stability that makes the mere 9 billion mark previously set by the cesium atomic clocks seem like sundials. The following video is a National Institute of Standards and Technology scientist discussing this improvement on video, along with explanatory text.
If all of this weren’t disconcerting enough for you, these atomic clock scientists have found that time varies with altitude as well. In experiments using aluminum atom atomic clocks, they have been able to demonstrate that these variations in time have an effect with each foot of elevation, meaning that our feet are in a different time zone that our heads (does this explain clumsiness? it’s at least a better excuse than “I can’t walk and chew gum at the same time!”). Over a 79-year lifespan, the difference would only amount to about 90 billionths of a second, but it is there all the same.
The whole point is that while we usher in the new year, we might give pause to remember that what we are celebrating is a not entirely accurate astronomical event. The earth has orbited around our sun for the past 365 days and will start that process again. In the meantime, sidereal time and atomic time—and Planck time for that matter—are all moving at rates that we can’t even comprehend unless we’re practicing the science of measuring—and improving—on atomic clocks and the electronic quantum transitions that are involved. From a practical standpoint, the next time you look at a second hand on a clock or watch a minute pass, consider the atom and all the changes it has gone through in that time. Consider that, as the earth rotates and precesses on its axis each day, we are each in our very own time zone. In fact, various parts of our bodies are in various time zones, particularly if you’re measuring our relatively enormous selves in Planck lengths.
So, Happy New Year! We have orbited our sun at the rate of 67,000 miles per hour—or if that seems too fast to you, let’s just say 19 miles per second—over the past roughly 365.256 days and yet, knowing these underlying facts, we will all count down to midnight in the enormously large seconds increments “ten-nine-eight-seven-six-five-four-three-two-one-happy-new-year!” and 6.144 hours later, the new orbit of the earth around the sun will start.
Not to be a party-pooper, but…
P.S. My introductory excerpt is not a serious question, it’s just a bit of good-natured trolling…