The Cassini’s unparalleled succession of weekly dives into Saturn and its rings reveals that the planet’s magnetic field has no apparent tilt. This eye opening observation asserts the fact that the true length of day of Saturn is yet unknown.
Other culmination of Cassini includes favorable hints about structure and composition of the icy rings and zenith resolution images of rings and Saturn’s atmosphere. Cassini is ranked as 15th of the 22nd weekly orbits that travels through the tapered gap between Saturn and its rings. It started its finale on April 26th and continues to dive until September 15th when it will make a plunge into Saturn’s atmosphere thereby ending its mission.
Cassini’s magnetometer instrument shows that Saturn’s magnetic field is well aligned with the planet’s rotation axis. The tilt is less than 0.06which is a lower threshold the spacecraft’s magnetometer data placed on the value before starting the Grand Finale.
This observation contrasts the idea of generation of magnetic fields. Planetary magnetic fields require some degree of tilt to bolster currents flowing through the liquid metal deep inside the planet. If there is no tilt then current would eventually subside and the fields would disappear. The tilt would help reveal the true length Saturn’s day.
The paucity of tilt can be corrected by obtaining the correct data. The data will be continually analyzed for the remainder of the mission including the final plunge.
The magnetometer data will also be measured in tandem with Cassini’s measurements of Saturn’s gravity field collected during the Grand Finale. Early analysis of the gravity data collected so far shows faults compared with parts of the leading models of Saturn’s interior, suggesting something unexpected about the planet’s structure is awaiting discovery.