Saturn's day lengthens by minutes - 04/05/2006
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Saturn is spinning slower than expected, scientists report.
An international team of researchers has calculated the rotation period is 10 hours and 47 minutes.
That's 8 minutes longer than estimates from the NASA Voyager results in the early 1980s.
It may not sound like a lot but the researchers say it could affect how we calculate the size of the planet's rock and ice core, and provide more insights into how it formed.
The team publishes its results today in the journal Nature.
'Making this measurement has been one of the team's most important scientific goals,' says Professor Michele Dougherty, of Imperial College London.
Astronomers have long tried to calculate the length of a Saturn day. William Herschel back in the late 18th century for example, suggested it lasted about 10 hours.
But the nature of Saturn itself makes measurements difficult.
Unlike Earth which has a rocky surface, Saturn is made up mostly of hydrogen and helium gases, which complicates how scientists measure the length of a day.
So rather than take direct measurements, scientists use proxies, or markers, of the planet's rotational period.
In the 1980s, scientists analysed radio signals from Saturn picked up by Voyager to calculate the length of day.
Now, Dougherty and US scientists used
Saturn is spinning slower than expected, scientists report.An international team of researchers has calculated the rotation period is 10 hours and 47 minutes.
That's 8 minutes longer than estimates from the NASA Voyager results in the early 1980s.
It may not sound like a lot but the researchers say it could affect how we calculate the size of the planet's rock and ice core, and provide more insights into how it formed.
The team publishes its results today in the journal Nature.
'Making this measurement has been one of the team's most important scientific goals,' says Professor Michele Dougherty, of Imperial College London.
Astronomers have long tried to calculate the length of a Saturn day. William Herschel back in the late 18th century for example, suggested it lasted about 10 hours.
But the nature of Saturn itself makes measurements difficult.
Unlike Earth which has a rocky surface, Saturn is made up mostly of hydrogen and helium gases, which complicates how scientists measure the length of a day.
So rather than take direct measurements, scientists use proxies, or markers, of the planet's rotational period.
In the 1980s, scientists analysed radio signals from Saturn picked up by Voyager to calculate the length of day.
Now, Dougherty and US scientists used
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