Sunday, February 19th 2012, 9:23 AM EST
In a recent article from National Geographic by Jason Major headed "Venus Spinning Slower Than Thought—Scientists Stumped", he mentioned the following..
Planet lovers take note: Venus is spinning even slower than astronomers thought, according to new data from a European space probe.
In the early 1990s scientists with NASA's Magellan mission calculated that a single rotation of Venus takes 243.015 Earth days, based on the speed of surface features passing beneath the orbiting spacecraft.
But scientists now mapping Venus's surface with the European Space Agency's Venus Express orbiter were surprised to find the same features up to 12.4 miles (20 kilometers) from where they were expected to be, based on the previous measurements.
According to the new data, Venus is rotating 6.5 minutes slower than it was 16 years ago, a result that's been found to correlate with long-term radar observations taken from Earth.
I could not help cast my mind back to the comments made about this effect by Piers Corbyn from Solar Cycle 25 to end "Man Made Climate Change" myth at SC25.com
Piers had this to say..
"The spin rate of the earth is generally being braked slightly by its interaction with the solar wind and as we get to a solar minimum this braking is less. That probably gives a sort of slow 'jolting effect on oceans and tectonic plates which might exacerbate earthquakes and tremors. We have to think of CHANGES in forces or changes in acceleration rather than simply forces or accelerations.
“Think of a train with its brakes on by a certain fixed amount - constant deceleration. You are sitting in your seat and the braking is thrusting you forward a bit but you have adjustyed for that and feel no discomfort. When the train comes to a stop this braking ends and you feel a jolt and you slump backwards into your seat as the force you provided to not fall forward pushes you back. Similarly when a train (or a plane) changes its acceleration forward you experience jolts.
Generally speaking in a train or plane plenty of jolts occur when they are hardly moving rather than moving at top speed.
In a similar fashion the oceans pressing against the continents or more precisely against some tectonic plates - experience jolts relative to the earth's main crust and core as the interaction with the solar wind changes as we get close to (or move away from) solar minimum.
So, according to the National Geographic article in the last 16 or so years Venus has been noticed to have slowed down, this as we have recorded, is in the same time frame that the Sun has reduced its high solar activity that started in the mid 1950's.
It looks to me that Piers is about right in his observations that during periods of low solar activity we see a speeding up of the planets, and when the Sun becomes active in these calm periods we would experiance a noticeable jolt to the Earth's tectonic plates whenever the Sun produces a "solar kick" towards our direction producing more powerful Earthquakes and Volcanic eruptions.
In times of high periods of solar activity the Earth's rotation is less likely to be influenced by these "solar kicks" as the Earth is at a continuous speed, as per comments from Piers
I would add to this that "The Little Ice Age" was such a period of a speeding up of our planet due to a reduction of the Sun's Solar output the Earth was more susceptible to Volcanic activity.
To say that the Earth cooled because of more Volcanic Activity does not give a complete picture of how our climate works during long periods of low solar activity. A cooler climate is the production of low solar activity in conjunction with the extra increase of Volcanic Activity when the Sun gives a "solar kick" that alters the speed of the Earth and the techtonic plate structure. Needless to say the very long term effect of low solar activity will add to this coolling process, just like the LIA
To prove this hypothesis we would need to observe if Venus has more Volcanic activity now that it has been shown to have slowed down from long term High Solar activity.
Venus will start to speed up again now the breaks are off from the solar wind, no doubt the next headline in a few more years will be "Venus Spinning Faster Than Thought—Scientists Stumped!!