I haven't seen anything in writting yet but it was on the national news last night that there will be no "Leap Second" this "Leap Year" because the Earth's rotation has been speeding up. It seems to me that this is a rather sudden change of events. The complete reversal of the historical notion that the earth's rotation was slowing down due to the tidal drag caused by the moons gravity and our oceans tides. Does anybody have more on this information?
http://dsc.discovery.com/news/briefs/20031229/atomicclock.html Note: until 5 years ago the Earth was slowing just as predicted. And as the article shows this can be tracked back for eons. Whatever has altered this is a recent effect. For example, as this article points out warmer climate can speed up the Earth's rotation. And since weather records do show that we have been experiencing warmer years world wide lately, IMO this seems a likely culprit.
that is fascinating, thanks for the link. the article said it was not that it was speeding up it was that it had, at least temporarily, "stopped slowing down" for a long time the trend is for the day to get longer by 1.5 millisecond per century. So if the second is defined so that now the day is exactly 86400.0000 seconds long, then in 2104 the day will be 86400.0015 seconds long So they have this plan of regularly inserting "interpolational" seconds to keep in step with this EXPECTED slowing. And then the earth faked them out by temporarily stopping the slowing process. So they had to hold back on 5 occasions and say wait! DONT sneak in the planned-for interpolational second. It is not clear, and someone said it was speculative and uncertain, how warming can affect the rotation rate as described by the dancer analogy. It could also have the opposite effect if the polar snow and ice diminished and sealevel around the equator rose (putting more mass further out, the way a dancer or skater can slow down a twirl) so I still have to wait till someone can give me a clearer explanation of whats going on.
Earth mass greater Their are a number of good articles on the earth second with the following source being just one, http://www.cl.cam.ac.uk/~mgk25/time/metrologia-leapsecond.pdf One of the issues that I never see mentioned is the fact that the earth is gaining mass ever so slowly from the constant influx of meteorites (stony and icy). There is a major problem in quantifying the amount of material being added, but I think the issue should be considered. Currere
Re: Earth mass greater this is outstanding, thanks! Have you seen this one? http://www.allanstime.com/Publications/DWA/Science_Timekeeping/TheScienceOfTimekeeping.pdf
scientific time interval Mark, No, I had not seen that article and I have added it to my collection. One of the questions raised on the first page of the article I referenced was this, "... would it be better simply to let atomic time run freely and accept that the world's civil time scale will slowly diverge from the rotation of the earth?" What they are actually trying to do is establish a "scientific time interval" that is close to 1/86,400th division of the earth's rotation. I think they are doing it backwards. It is possible to identify a "scientific time interval" that can be defined mathematically (quite simply), then all they need to do is develop instruments that emulate the mathematically perfect time interval as close as they can. The civil time people can then go about providing the processes that keep "commerce" synchronized, and the scientific types will have an unchanging reference (which will simply be emulated to a greater precision as hardware is improved). I have a quote, stored away somewhere on this or my old computer, attributed to Arthur C. Clarke, which essentially referred to the earth second as provincial.
Re: scientific time interval Please Register or Log in to view the hidden image! I seem to recall that if we switched to the Planck time unit (2002 CODATA recommended value posted at NIST constants site) or more exactly to half-second-like units of 10<sup>43</sup> Plancks each, then there would be right around 160,261 of them in one day. It might then be objected that the choice of the number 10 was provincial.
the earths seames to be speeding up what pritty soon the news is going to tell use we are spinning like tops.
In some other newssources we can find earth magnetic field anomalies shifting and weakening of the earth magnetic field in general. It could even be a prelude to a magnetic polar reversal within the next 10.000 years. Maybe part of the speedup, is related to electrodynamic behaviour of the core
