Magnetosphere of Jupiter By 1973 the magnetic moment was known within a factor of two, whereas the tilt was correctly estimated at about 10°. The modulation of Jupiter's DAM by Io (the so-called Io-DAM) was discovered in 1964, and allowed Jupiter's rotation period to be precisely determined. The definitive discovery of the Jovian magnetic field occurred in December 1973, when the Pioneer 10 spacecraft flew near the planet. As of 2009 a total of eight spacecraft have flown around Jupiter and all have contributed to the present knowledge of the Jovian magnetosphere. The first space probe to reach Jupiter was Pioneer 10 in
Ceres (dwarf planet) quadrangles. They are named after the first craters whose names the IAU approved in July 2015. The map image(s) were taken by the "Dawn" space probe. Ceres (dwarf planet) Ceres (; minor-planet designation: 1 Ceres) is the largest object in the asteroid belt that lies between the orbits of Mars and Jupiter, slightly closer to Mars' orbit. With a diameter of , Ceres is the largest of the minor planets, and the only dwarf planet, inside Neptune's orbit. It is the 33rd-largest known body in the Solar System. Ceres is composed of rock and ice and is estimated to comprise