ThomasIsUnderrated
06-29-2004, 04:54 PM
http://www.nasa.gov/images/content/61428main_pia05413-516.jpg
Image credit: NASA/JPL/Space Science Institute.
On approach to Saturn, data obtained by the Cassini spacecraft are already posing a puzzling question: How long is the day on Saturn?
Cassini took readings of the day-length indicator regarded as most reliable, the rhythm of natural radio signals from the planet. The results give 10 hours, 45 minutes, 45 seconds (plus or minus 36 seconds) as the length of time it takes Saturn to complete each rotation. Here's the puzzle: That is about 6 minutes, or one percent, longer than the radio rotational period measured by the Voyager 1 and Voyager 2 spacecraft, which flew by Saturn in 1980 and 1981.
Cassini scientists are not questioning Voyager's careful measurements. And they definitely do not think the whole planet of Saturn is actually rotating that much slower than it did two decades ago. Instead, they are looking for an explanation based on some variability in how the rotation deep inside Saturn drives the radio pulse.
<EMBED SRC="http://www.nasa.gov/61424main_sat-rot-wav.wav" WIDTH=145 HEIGHT=100 AUTOSTART="true"></EMBED>
These sounds of radio emissions from Saturn have been compressed in time so that one second corresponds to one rotation of the planet.
Read it all HERE (http://www.nasa.gov/mission_pages/cassini/media/cassini-062804.html)
Image credit: NASA/JPL/Space Science Institute.
On approach to Saturn, data obtained by the Cassini spacecraft are already posing a puzzling question: How long is the day on Saturn?
Cassini took readings of the day-length indicator regarded as most reliable, the rhythm of natural radio signals from the planet. The results give 10 hours, 45 minutes, 45 seconds (plus or minus 36 seconds) as the length of time it takes Saturn to complete each rotation. Here's the puzzle: That is about 6 minutes, or one percent, longer than the radio rotational period measured by the Voyager 1 and Voyager 2 spacecraft, which flew by Saturn in 1980 and 1981.
Cassini scientists are not questioning Voyager's careful measurements. And they definitely do not think the whole planet of Saturn is actually rotating that much slower than it did two decades ago. Instead, they are looking for an explanation based on some variability in how the rotation deep inside Saturn drives the radio pulse.
<EMBED SRC="http://www.nasa.gov/61424main_sat-rot-wav.wav" WIDTH=145 HEIGHT=100 AUTOSTART="true"></EMBED>
These sounds of radio emissions from Saturn have been compressed in time so that one second corresponds to one rotation of the planet.
Read it all HERE (http://www.nasa.gov/mission_pages/cassini/media/cassini-062804.html)