Tables of APXS results are also available for the soils. Soil experiments using the rovers wheels to dig in the ground show a friction angle equal to the angle of repose of 38 degrees, and soil friction of 0.2 kilopascal. Other areas and soils may be different. This information will be used to estimate thermal inertia and radar reflectivity properties. The magnetic materials experiment shows dust collecting through time on the three strongest magnets after 26 days.
Preliminary analysis indicates the possibility that all martian dust is at least slightly magnetic.
The dust is believed to contain maghemite, a strongly magnetic mineral formed in environments of scarce oxygen. Further information on maghemite is available. Geophysics A study which measures the Doppler shift in radio transmissions from the lander has shown that Mars may have a solid iron core. The Doppler shift of the received radio signals gives an accurate determination of the relative velocity of the lander and Earth due to the spin of the Earth, movement of Mars and Earth in their orbits, and spin of Mars. This in turn can give an accurate estimate of the martian rotation rate, spin-axis direction, precession, etc.