The earth is known to rotate on its own axis. This is called the rotation of the earth and is the reason for the constant and regular change from day to night. A day lasts 24 hours, and most people will be all too familiar with that, after all, our everyday life and even our internal clock are geared to it.
However, scientists have now found that June 29 of this year was a little shorter and thus the shortest day since records began using atomic clocks in the 1960s. Conversely, this means that the earth has rotated faster than it has in the last 60 years or so. The researchers are puzzled as to how timeanddate.com reported.
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How much shorter was June 29th?
A normal day, or more precisely sunny day
, lasts 24 hours or 86,400 seconds. This is the mean time span between the highest position of the sun from one day to the next. June 29 deviated from this by almost exactly 1.59 milliseconds. That sounds like little, but it is significantly more than such deviations usually amount to. Normally, researchers calculate with a difference to the standard solar day of around one millisecond. This is perfectly normal. Most days are shorter or longer by a thousandth of a second.
This is because the earth is subject to various gravitational forces. The distance to the moon, for example, fluctuates constantly, which in turn influences the tidal forces and thus the earth’s rotation. In addition, the earth is not a perfect sphere, but rather resembles a potato – keyword: Potsdam potato. To be precise, the earth is an almost spherical ellipsoid of revolution.
Solar day versus sidereal day
In addition to the solar day, there is also the sidereal day. Sidus is Latin and means star in Europe. This is a bit confusing because it doesn’t mean the sun, but a fictitious star. The sidereal day is therefore not calculated on the basis of our central star, but takes the cosmic background assumed to be at rest as a reference point. A sidereal day lasts 23 hours 56 minutes and 4.0905 seconds.
Why June 29 was now shorter is a mystery to the scientists. It’s not the first record either. For several years, the rotation of the earth has been setting new speed records.
Possible reasons for this are processes inside the earth, tidal forces, oceans and even climate change. Also, the change of geographical poles, the so-called Chandler wobble
, is mentioned as a potential cause. However, the exact reason is not yet known with absolute certainty.
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Does the faster rotation of the earth have consequences for us?
Don’t worry, we’re in no danger of being ejected from the earth. The worst possible scenario is that we lose a second. If the Earth’s rotation continues to freak out, it could be that our clocks have to skip a second so that atomic clocks and solar time match again.
Overall, however, the trend is pointing in a completely different direction anyway: Actually, the Earth’s rotation slows down over time. This means that the days are getting longer by about one millisecond every century. This is also due to the tidal friction exerted by the moon. To put it simply, the earth has been slowed down successively since the moon was formed. However, these are long-term changes, unlike the short-term fluctuations described in this article.
How do you like that? Are you interested in such topics? Or do you think 1.59 milliseconds is almost too little to even think about it? Write it to us in the comments!