Is the rotation speed of the Earth slowing down? Yes it is. Astronomers can measure this very precisely now that they have atomic clocks to provide a non-celestial time standard for comparison. The length of the day is increasing by 0.0015 seconds every century, of which about 0.0007 seconds per century has to do with the tidal breaking of the Moon. As a result of this, the Moon's orbit must also increase so that the Moon is slowly getting farther and farther from the Earth by a few centimeters per year [approx]. As this process continues, it is predicted that in billions of years the lunar month will increase to about 47 days from its current 27.3 days. But by that time, the Sun itself will have begun to evolve into a red giant, which will upset the Earth-Moon system somewhat; especially if they are both engulfed by the Sun's expanding atmosphere!
When the Earth was very young, its faster rotation caused it to have a much larger equatorial circumference than it has at the present time. It may have been spinning fast enough to have a "Saturn type ring" around it.
It is well known that the rotation of planet Earth is gradually slowing. For four and one half billion years, its entire lifetime, its rate of rotation has been gradually slowing. As the Earth loses its kinetic energy due to all forms of friction acting on it; tides, galactic space dust, solar wind, space weather, geomagnetic storms, etc., like any flywheel, it will slow down. (The space surrounding the planet is far from empty). While we know the Earth's rotation is slowing that is not the main reason why the extra "Leap Second" was added by our official time keepers this year. The reason for adding a leap second is that the planet does not rotate exactly once every 24 hours (86,400 seconds). The rotation actually takes 86,400.002 seconds so that each day this little difference builds up between the atomic clock and the earth's rotation.
When the difference builds up enough (.9 seconds), the time keepers must add another second (leap second) to keep the stars location, relative to the planet's rotation, in exact sync with the superaccurate atomic clocks.
The Earth's rotation is slowing but at a much slower rate than 1 leap second every so many years. The length of time it takes the Earth, at the present time, to rotate once is 86,400.002 seconds compared to 86,400 seconds back in 1820. The rotation has slowed roughly only by 2 milliseconds since 1820. That seems like an insignificant amount of time BUT over the course of the planet's entire lifetime, it has had very profound effects on the geophysics of the planet.
It has caused mountains to rise, earthquakes, etc. to occur as we will see. This article is about, factoring in the tremendous geophysical activity that was caused, by the Earth's slowing rotation, in the interior of the planet, its crust, oceans and atmosphere over its entire lifetime.
The Sub-bureau for Rapid Service and Predictions of Earth Orientation Parameters of the International Earth Rotation Service (IERS), located at the US Naval Observatory, monitors the Earth's rotation. Part of its mission involves the determination of a time scale based on the current rate of the rotation of the Earth.
They estimate that the Earth's rotation is slowing at about 1.4 milliseconds per solar day per century which roughly agrees with the rate of rotation of the Earth has actually slowed down since 1820.
Tracing these tiny milliseconds back for 4.5 billion years adds up to a very significant amount of time for a solar day. I have determined that the day/night rotation was 63,000 seconds shorter than the present 86,400 seconds it is today. This would put the Earth's rotation at about 6.5 hours per day/night cycle, when it was created, 4.5 billion years ago. (This is a much faster rate of rotation than the Cassini-Huygens mission (2003 to 2004) determined Saturn's 10.5 hours rotation period to be.)
This rate of rotation would have exerted tremendous stress throughout the newly formed planet. If the rate of rotation has been slowing fairly constantly, over the ages, we can see that the earth was rotating very fast originally, for it to slow down to the present 24 hour rate it is today. What ever it was - its angular momentum was much faster and therefore its "centrifugal force" was tremendously strong when the planet was very young. This caused the young, fast spinning, Earth to have a much more pronounced oblate shape, possibly even having a "Saturn type ring" orbiting around it.
