spacetoday.net: Astronomers discover decrease in Saturn winds

Posted: Fri, Jun 6, 2003, 7:00 PM ET (2300 GMT)
Saturn seen by Hubble (NASA/STScI)

Winds in the atmosphere of Saturn's equatorial region have dropped dramatically in the last two decades, possible evidence of seasonal changes on the planet, astronomers reported this week. In a paper published in the latest issue of the journal Nature, Spanish and American scientists reported their measurements of Saturn's winds between 1996 and 2002 using images from the Hubble Space Telescope. They found that the winds in the equatorial region were about 990 kmph, nearly half the 1,700 kmph measured by the Voyager spacecraft in 1980-81. While planetary scientists had believed that Saturn's winds were driven in large part by the planet's own internal heat source, this discovery suggests that solar heating may play a role; the change in seasons over the last 20 years could explain the decrease in wind speeds. The researchers also noted that the wind speeds measured in the Hubble images may have been at a higher region of the atmosphere than the Voyager data, which would also explain the lower speeds.