That is exactly what has happened recently. NASA's Cassini spacecraft found that the natural radio wave signals coming from the gaseous giant planet are different in the northern and southern hemispheres. This tells scientists that the two hemispheres have time lengths for a day (a day is defined as the time it takes a planet to make a complete rotation about its axis in respect to the sun). How can two hemispheres on the same planet have a different time period for a day? I mean they are on the same planet so that just does not make any sense.
Please don't be confused here. I am not talking about the length of time that a location on a Saturn, Earth or any planet sees sunlight, normally referred to a daylight hours. This amount of time DOES change from location to location and from season to season. I'm talking about a complete rotation, so from noon to noon on a planet. This amount of time DOES NOT change.
Scientists measured, by a method of reading these radio waves, that the length of a day on Saturn at the north pole was 10.6 days while at south pole it was 10.8 days. Making this puzzle even stranger is that researchers noticed that the length of the day, again measured by the radio wave method, changed for each hemisphere. The south's time period decreased while the north's increased until they met at about 10.67 hours (boy this planet is moving fast around the sun compared to the Earth considering how large the planet is and that it completes an entire rotation in less than half the time). Then the times diverged yet again!
Strange stuff indeed. "This data just goes to show how weird Saturn is," said Don Gurnett of the University of Iowa, who leads Cassini's radio and plasma wave instrument team, in a statement. "We thought we understood these radio wave patterns at gas giants, since Jupiter was so straightforward. Without Cassini's long stay, scientists wouldn't have understood that the radio emissions from Saturn are so different."
So what is the explanation of the strange phenomena going on here? Cassini scientists don't think the differences in radio wave periods have to do with Saturn's hemispheres actually rotating at different rates. As mentioned above, that is just not physically possible and would not make sense.
More likely, the signal changes are caused by variations in Saturn's high-altitude winds. The behavior of Saturn's magnetosphere is also likely having an impact.
A clue that the magnetosphere is having something to do with the strange radio signals is that the auroras shifted position in sync with the changes of the measurement of Saturn's day. "The rain of electrons into the atmosphere that produces the auroras also produces the radio emissions and affects the magnetic field, so scientists think that all these variations we see are related to the sun's changing influence on the planet," said Stanley Cowley of the University of Leicester, a Cassini scientist and a co-author on the two recent Saturn magnetic field papers.
The Cassini spacecraft will be in orbit around Saturn until at least 2017. So, if there are any more questions about these strange radio signals or anything else going on about this huge planet we may be able to get some answers.