Iapetus has preserved evidence that constrains the modeling of its geophysical history from the time of its accretion until now. The evidence is (a) its present 79.33-day rotation or spin rate, (b) its shape that corresponds ...

New CCD photometry of the faint, compact star cluster IC 1257 (L = 17? = ± 15?obtained with the Palomar 5m telescope, reveals that it is a highly reddened globular cluster well beyond the Galactic center.

Three radii from the surface of the Sun...more natural radiation around Jupiter than would be encountered immediately following a nuclear war...to the farthest planet and beyond...these challenges are faced by the three ...

Jupiter's icy satellites Europa, Ganymede and Callisto are subject to energy fluxes from electrons, photons and magnetospheric plasma ion bombardment.