The interplanetary magnetic field at earth distance is 1 to 37 nT, with an average value of ~6 nT. At Mar's distance it would average about 3 nT.<br /><br />Faraday's Law gives the voltage induced in a wire sweeping through a magnetic field.<br /><br />V = B x A<br />V = voltage<br />B = field strength in Teslas<br />A = area swept by the wire in meters^2/sec<br /><br />The orbital speed of Mars is 25km/sec or 25,000 m/sec<br /><br />Suppose we laid out a 100km wire on the surface of Mars.<br /><br />V = 3x10^-9 Tesla x 25000 m/sec x 100,000 m = 7.5 volts.<br /><br />The problem is that the return wire generates the same voltage, thus no current flows. If you ran the return wire around the opposite side of Mars, then the field strength there would be a bit weaker, thus some net voltage would be generated thus some current would flow.<br /><br />Another strategy would be to wind a coil from pole to pole and use the spinning of Mars to generate a voltage, ignoring the speed it revolves around the sun. The diameter of Mars is 6700 km. The average radius of the coil would be 1/4 that or 1700 km. Circumference is 5000 km. Speed is 60 meters/sec. Swept length of coil is 2D or 13,400 km. <br /><br />V = 3x10^-9 Tesla x 60 m/s x 13,400,000 m = 2.4 volts. <br /><br />One circum-Mars coil would produce 2.4 volts. If it was made out of #2 copper (1/4 inch diameter) the resistance would be .16 Ohm/kft. A coil around Mars would be 22000kft or 3500 Ohms. A short circuited coil would flow with .6 milliamp of current at 2.7 volts producing 1.6 milliwatts of power - all of which would be dissipated as heat. If we could make the coil out of superconducting metal then that power would be ours to use. A million turns of wire around the planet would produce 1600 Watts of power.<br /><br />Lemons with nails in them would be a better bet. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>