This may be a litle off thread, but demonstrates the difficulties of practical predictions of supposedly well known things.
One might assume that the Earth would have constant rotational speed, or at least that its rate of slowing down due to tidal friction would be constant, to a usable degree. The assumption would be wrong.
The following is from an article written by the Director of the U.S. Naval Observatory, and a past head of the USNO’s Time Services Dept.
“During the mid-1930s, astronomers concluded the Earth did not rotate uniformly, basing their findings on measurements of the most precise clocks then available. We now know that a variety of physical phenomena affect the Earth’s rotational speed. This caused the second to be redefined in 1960 in terms of the Earth’s orbital motion around the Sun. The new second was called the “Ephemeris” second and the time scale derived from this definition was called Ephemeris Time (ET).”
Another quote –
“Although we have accurate estimates of the deceleration of the Earth’s rotation, significant variations prevent the prediction of leap seconds beyond a few months in advance. This inability to predict leap seconds, coupled with the growing urgency for a uniform time scale without discontinuities, makes it appropriate to re-examine the leap second’s role.”
Two points arise. The first is that observations show the Earth does not rotate uniformly. As an aside, I believe it slows down and speeds up erratically.
The second is that even with astronomical observations going back to the 1600s, and accumulated scientific knowledge to date, it is impossible to predict leap seconds more than a few months in advance. And we are talking about a fairly massive body here – slowing down and speeding up enough to be of concern. A GPS system depends on accurate timekeeping, and microseconds are important, let alone a million of the little beggars!
So, if accurately predicting the rotation of the Earth more than a few months in advance, at most, is impossible, how much more difficult must it be to predict weather and climate, if the atmosphere behaves chaotically?
If a butterfly flapping its wings in the Brazilian rainforest can cause a tornado in Kansas, imagine the effect the whole Earth slowing down or speeding up might have, Throw in a few factors such as continents slowing down and speeding up, changing direction at random, bobbing up and down without rhyme or reason, and it easy to see why highly trained and qualified experts, backed up by billions in research and with access to previously unimaginable computing power, cannot forecast weather any better than a reasonably intelligent 12 year old, given an hours coaching.
So yes, analysis of a data series, whether it be corn futures, stock market movements, temperatures, or any number of other things, can often lead to the conclusion that are composed, in part, of various regular waves. Unfortunately, the predictive power of such extracted waves is generally nil, as economists, hedge fund operators and others have discovered to their sorrow.
You may well find patterns, waves, synchronicities and correlations wherever you look. It is in our nature, I believe.
Just an opinion on the usefulness of waves extracted from the data produced by a probably chaotic system – the Earth on which we live.
Live well and prosper,
Mike Flynn.