Expert: Jayendra Upadhye - 4/10/2004

Question
Are the magnetic axes of all 4 giant planets aligned with their spin axes?

and is it true that the magnetic fields on both Uranus and Neptune arise in the metallic hydrogen layer that surrounds their cores?

Thanks a lot

-James

Answer
Hi James,
The outer gas giants of the solar syatem fall into two catefories. Those with a shell of liquid metallic hydrogen, and those with a convecting ice mantle.
Jupiter and saturn fall in the first category while Uranus and Neptune in the second category.
The magnetic fields of all these are very large but those of
Uranus and Neptune fall within the range topped by jupiter and saturn with earth at the lower end of the scale.

The magnetic fields of Uranus and Neptune are roughly 50 and 25 times stronger than that of the earth.

Uranus has its magnetic field tilted at 58.6 deg with respect to its rotational axis.

Neptune's magnetic axis is tilted 47 deg with respect to its rotational axis and most strikingly it is offest from the planetary center by a good 13600 km!

The site http://members.shaw.ca/evildrganymede2/JTAS/magfield.htm gives a lot of additional info too.
Jayen