Imagine a very long, uniform wire that has a linear mass density of 0 . 0012 kg / m and that encircles the Earth at its equator. Assume the Earth's magnetic dipole mo- ment is aligned with the Earth's rotational axis. The Earth's magnetic field is cylindri- cally symmetric (like an ideal bar magnetic). The acceleration of gravity is 9 . 8 m / s 2 and the magnetic field of the earth is 2 × 10 ? 5 T . What is the magnitude of the current in the wire that keeps it levitated just above the ground?