When we look at the magnetic field in ancient igneous rocks…
When we look at the magnetic field in ancient igneous rocks on the Earth, we find that rocks of the same age have magnetic fields that point in different directions, like the top map below. Someday in the future, scientists would like to make similar measurements on Mars. If we were to measure the magnetic fields trapped in ancient igneous rocks on Mars, scientists expect to find that the magnetic field in rocks of the same age will all point the same direction, like the bottom map. What would cause them to be different? Attributions Images Strebe. Gall–Peters projection SW.jpg . (CC BY-SA 3.0). Via Wikimedia Commons.