Earth’s Magnetic Field ~Magnetosphere

1. Earth’s Magnetic Field~Magnetosphere

2. Earth’s Magnetic Field • The Earth acts like it has a giant bar magnet buried in it. • The magnetic field of the Earth is caused by convections currents of the molten iron and nickel interior of the Earth

3. Geographic and Magnetic Poles • Geographic poles- points the Earth rotates about. • Magnetic poles- where a compass points to • Thy are not exactly the same place, but they are close. • Magnetic poles actually move about 10-40 km a year. • Magnetic south is up north and vice versa. • Geographic north is in the Artic ocean magnetic south is in northern Canada

4. Geographic North, Magnetic South Poles Russia (Siberia) Artic Ocean Red Stars show Magnetic South at different times Northern Canada

5. Compass • A compass- in a thin magnet on a string or floating in a liquid. (Used for navigation) • The north pole of a magnet is attracted to the magnetic south pole of the Earth. • magnetic declination-error in compasses because they point mag. south. This is small unless you are near the poles.

6. How does the Earth’s magnetic field keep me alive? • The sun releases solar wind (charged particles and radiation) • If all of this hit the surface of the Earth, life as we know it would end. • The Earth’s magnetic field (magnetosphere) deflects these particles.

8. Auroras • Some of this radiation gets trapped in the magnetosphere and runs from pole to pole. (in the Van Allen Belts) • Near the poles it hits more air in the atmosphere and causes the sky to glow. • These are called auroras • Aurora Borealis (Northern Lights) • Aurora Australis (Southern Lights)

9. Auroras

10. Other astronomical magnetic fields • The Sun has a strong magnetic field that flips polarity every 11 years. • This field causes sun spots (seen as dark spots on the surface) • Several planets also have a magnetic field or magnetosphere. • Jupiter and Saturn do, Venus does not