WEBVTT FILE 1 00:00:00.000 --> 00:00:00.930 2 00:00:00.950 --> 00:00:01.830 Earth 3 00:00:01.850 --> 00:00:04.570 spinning through the solar system, 4 00:00:04.590 --> 00:00:07.620 proudly bearing a majestic magnetic field 5 00:00:07.640 --> 00:00:11.230 emanating deep within its molten metallic core. 6 00:00:11.250 --> 00:00:12.590 The ever-changing field 7 00:00:12.610 --> 00:00:13.880 is full of fluctuations 8 00:00:13.900 --> 00:00:16.160 from many sources. 9 00:00:16.180 --> 00:00:18.460 Satellites observing these oscillations 10 00:00:18.480 --> 00:00:20.030 let scientists identify 11 00:00:20.050 --> 00:00:21.110 individual sources 12 00:00:21.130 --> 00:00:23.410 creating the magnetic field. 13 00:00:23.430 --> 00:00:27.070 One such source is the motion of the ocean. 14 00:00:27.090 --> 00:00:30.100 As the ocean flows, the field lines feel a pull 15 00:00:30.120 --> 00:00:32.010 and are dragged along a little. 16 00:00:32.030 --> 00:00:33.570 The back-and-forth of the tides 17 00:00:33.590 --> 00:00:37.550 cause a small wiggle in the magnetic field. 18 00:00:37.570 --> 00:00:39.360 Scientists have isolated this 19 00:00:39.380 --> 00:00:41.480 one small, oceanic signal, 20 00:00:41.500 --> 00:00:43.070 measuring it from a satellite, 21 00:00:43.090 --> 00:00:46.080 orbiting high above our spinning globe. 22 00:00:46.100 --> 00:00:46.530 23 00:00:46.550 --> 00:00:48.980 [ beeping ] 24 00:00:49.000 --> 00:00:53.800