The internal structures of giant planets are much
less well known than those of main - sequence stars because of
uncertainties in the equation of state of degenerate gas, the composition (typically non-solar), the interaction with the magnetic field and, in the upper layers, the
relative magnitudes of internal heat and energy deposited from the sun.
Typical instrument - related
relative measurement
uncertainties as derived from previous experiments are
less than ± 6 % (for 0.9 > Φf > 0.1)[31].