Dipole model of the Earth's magnetic field (MLAT), or geomagnetic latitude, formula_10 is measured northwards from the equator (analogous to geographic latitude) and is related to formula_9 by formula_12. In this case, the radial and azimuthal components of the magnetic field (the latter still in the formula_9 direction, measured from the axis of the north pole) are given by formula_14 formula_15 formula_16 where formula_17 in this case has units of Earth radii (formula_18). Invariant latitude is a parameter that describes where a particular magnetic field line touches the surface of the Earth. It is given by formula_19 or formula_20 where formula_21 is the invariant latitude and formula_22
The Edge of the Earth EP", which was released in September 2013. The second track, "Against the Voices", has been a "long-time fan favorite," as the song was first played by the band live in 2010. However, it hadn't made the cut for Switchfoot's two previous full-length albums, "Vice Verses" (2011) and "Fading West" (2014). According to the band, the song "What It Costs" marked the first song recording for which bassist Tim Foreman provided lead vocals, replacing his brother Jon Foreman. The Edge of the Earth The Edge of the Earth is an extended play by American rock band Switchfoot, released digitally on September