Does the Earth's rotational velocity ever accelerate positively and/or negatively by even just a bit at least?!?
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answers:
wildimagination2003 say: The Moon is getting slightly further away from the Earth at a tiny but ever-increasing amount. The closer it is to Earth (i.e millions or even a few billion years ago, it was considerably closer than it is now), the greater, more frequent and violent our tides would be and the days would be noticeably shorter. As a result, the Earth's spin rotation would have been faster than it is now - but in terms of perhaps a weekly or monthly or even yearly rotation rate changes, it'd be negligible I'd guess.
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Phillip say: Yes, both. Over the long run, it is slowing down a bit.
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Jim Moor say: Depends on how accurately you measure it!
Yes, it is slowing down every day. But by a super tiny part.
If the day seems a little longer than usual on Saturday, June 30, 2012, that's because it will be. An extra second, or "leap" second, will be added at midnight to account for the fact that it is taking Earth longer and longer to complete one full turn—a day—or, technically, a solar day.
"The solar day is gradually getting longer because Earth's rotation is slowing down ever so slightly," says Daniel MacMillan of NASA's Goddard Space Flight Center in Greenbelt, Md.
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kurisutarusqueaker say: No. If the earth sped up or slowed down, that would pretty much mean the end of the world for us.
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Bulldog redux say: Day length is increasing at the rate of about one second every 50,000 years. That's a decelaration.
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daniel g say: Real world, no, but tidal pulls do have some minuscule effect on rotation.
Humans have been relying on the steady rotation for celestial navigation for a hundred centuries, and takes time to an arc second to be accurate.
That "bit" you speak of does not fall into any math equations, and hardly significant even in deep space astronomy.
Perhaps the greatest concern is accurate calibration of the atomic clock of the NBS.
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Ronald 7 say: The Earth's spin is being gradually slowed down by Tidal Friction from the Moon
At the same time, The Moon being less massive is gaining Velocity
It is already Tidally locked to Earth showing the same face constantly
We will never lose the Moon, by the time it has reached its optimum Velocity and Altitude, Earth will be tidally locked with the Moon with a six day spin and six day orbit
The same as Pluto and Charon
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oubaas say: Earth is constantly slowing down due to friction
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billrussell42 say: that is the length of the day, and it does vary by a tiny amount. Those are corrected occasionally by leap seconds added or subtracted from a day.
wikipeida
Mainly due to tidal effects, the Earth's rotational period is not constant, resulting in minor variations for both solar days and stellar "days". The Earth's day has increased in length over time due to tides raised by the Moon which slow Earth's rotation. Because of the way the second is defined, the mean length of a day is now about 86 400.002 seconds, and is increasing by about 1.7 milliseconds per century (an average over the last 2 700 years).
In order to keep the civil day aligned with the apparent movement of the Sun, a day according to Coordinated Universal Time (UTC) can include a negative or positive leap second. Therefore, although typically 86 400 SI seconds in duration, a civil day can be either 86 401 or 86 399 SI seconds long on such a day.
Leap seconds are announced in advance by the International Earth Rotation and Reference Systems Service (IERS), which measures the Earth's rotation and determines whether a leap second is necessary.
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Bill say: A=F/M. What would the force be?
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Tom S say: Yes, slowing slightly.
https://www.sciencemag.org/news/2016/12/...
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drake say: It’s slowing down due to the gravitational pull of the moon
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ReductioAdAstronomicus say: It decelerates a little due to friction caused by the water sloshing about in tides.
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quantumclaustrophobe say: It does...
On occasion, there's an Earthquake that will *slightly* decrease the radius of the Earth; it changes our rotational velocity, making it a tiny bit faster.
In addition, the tidal effects of the moon are *slowing* the Earth; as the moon moves further out in it's orbit, the energy that's causing this is being robbed of our rotational momentum - and, our day grows by a very tiny amount every year.
Here's an article by NASA about how the Japanese quake a few years back changed the length of day: https://www.nasa.gov/topics/earth/featur...
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Deulofeu Heart of the Blues say: Stephen hawking proved wrong
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