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
Planet Us to pass up. I am happy these tracks are finally coming out." Planet Us was the second project that Hagar and Schon formed, the first being the short-lived Hagar Schon Aaronson Shrieve from the mid-1980s. Although it seems unlikely that they will regroup and produce a proper album, Neal Schon has left the door open stating "If he (Hagar) calls me up and says 'Schon – let's go'. I'm gone and it'll be fun." Satriani, Hagar and Anthony would later join forces for another band named Chickenfoot; that band formed in 2009. Planet Us Planet Us (pronounced "Planet-uss") was a