Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Earth's magnetic field Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Simple English Earth's magnetic field Simple English Simple English Simple English Simple English Simple English