Posted on 08/02/2022 3:50:41 AM PDT by Lonesome in Massachussets
Ever feel like there’s just not enough time in the day? Turns out, you might be onto something. Earth is rotating faster than it has in the last half-century, resulting in our days being ever-so-slightly shorter than we’re used to. And while it’s an infinitesimally small difference, it’s become a big headache for physicists, computer programmers and even stockbrokers.
Why Earth rotates
Our solar system formed about 4.5 billion years ago, when a dense cloud of interstellar dust and gas collapsed in on itself and began to spin. There are vestiges of this original movement in our planet’s current rotation, thanks to angular momentum — essentially, “the tendency of the body that's rotating, to carry on rotating until something actively tries to stop it,” explains Peter Whibberley, a senior research scientist at the UK’s National Physical Laboratory.
Thanks to that angular momentum, our planet has been spinning for billions of years and we experience night and day. But it hasn’t always spun at the same rate.
Hundreds of millions of years ago, Earth made about 420 rotations in the time it took to orbit the Sun; we can see evidence of how each year was jam-packed with extra days by examining the growth lines on fossil corals. Although days have gradually grown longer over time (in part because of how the moon pulls at Earth’s oceans, which slows us down a bit), during humanity’s watch, we’ve been holding steady at about 24 hours for a full rotation — which translates to about 365 rotations per trip ’round the Sun.
As scientists have improved at observing Earth’s rotation and keeping track of time, however, they've realized that we experience little fluctuations in how long it takes to make a full rotation.
(Excerpt) Read more at astronomy.com ...
I feel the same way. Conservation of energy seems to argue against things speeding up on their own.
The only thing I can think of is an analogy to an ice skater in a spin with their arms extended. As they bring their arms into their body, the speed of the spin increases. I’m not sure I see how the earth would be doing anything similar, but perhaps through gravitational compression (or something) maybe our spin is getting “tighter” and therefore faster.
But in general I distrust science and I agree that some people foolishly conclude that “better measurements” means that “things are changing”. And that is not necessarily so.
My bathroom scale tells a different tale. Either that or gravity is increasing.
The last leap second added was on December 31, 2016 at 23:59:60 UTC.
I’ve seen a couple of articles recently about leap seconds. Perhaps they are about ready to add one. It’s pretty much a non-issue. There are very few applications that it even matters for, and if they don’t have procedures for how to deal with it, they are morons.
Thanks Lonesome in Massachussets.
[snip] The question of how tidal friction affects the evolution of the Earth–Moon system has a long history. It dates back to 1695, when Halley noted an apparent unexplained discrepancy between ancient and actual eclipse timings. A conclusion in terms of lunar acceleration caused by the transfer of angular momentum from the Earth into the lunar orbit was offered by Dunthorne (1749). [/snip]
https://www.sciencedirect.com/topics/physics-and-astronomy/tidal-friction
https://www.google.com/search?q=tidal+transfer+of+momentum
"Lunar Origin" keyword excerpt, sorted:
Perhaps that is why the earth’s rotation has increased. Apply a force to a spinning gyroscope and see what happens.
(Okay, for those just tuning in this is meant to be humor.)
Changes in the distribution of mass can account for an increase in rotation rate, the canonical example being the ice skater drawing in her arms.
There is a long term slowing of the rate of rotation attributed to tidal braking. As the earth rotates the ocean tides lag and exert a torque on the moon’s orbit. Energy is lost by the waves breaking on the shore, angular momentum is preserved by transfer of angular momentum to the moon’s orbit. If not for the loss of energy the earth-moon system would experience libration, as the exchange of momentum caused the earth to alternately speed up and slow down, while the moons orbit would grow and shrink. The moon is already tidally locked to the earth, if the earth-moon system endures another 50 billion years, or so, the earth-moon will be mutually tidally locked, like Pluto-Charon, but the period of the day (and consequently the month) would be about 48 current days.
This is from Wiki Commons, but the data is from IERS (International Earth Rotational Services) that monitors the orientation of the earth with respect to "fixed stars". The red line is the cumulative deviation of the rotation of the earth from a 24 hour day, the red dots are leap seconds, corrections to UTC. The green line is the smoothed measured "excess length of day", the gray line is the unsmoothed measurements of the length of day. The green line is the derivative of the red line. If it stays negative long enough, we will need to subtract leap seconds.
Perhaps there is movement of denser materials (magma, etc.) that is migrating towards the center of the earth - drawn by the gravitational forces??
Dog Years (by RUSH)
In a dog’s life
A year is really more like seven
And all too soon a canine
Will be chasing cars in doggy heaven
It seems to me
As we make our own few circles ‘round the sun
We get it backwards
And our seven years go by like one
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