Picture from September 20, 2010
This APOD picture shows the aurora borealis over Norway. Also called the northern lights, this wondrous phenomenon actually depicts Earth's magnetic field struggling to ward off charged particles from the sun. Since the magnetic field is weakest near the poles, some of these particles get through and collide with air molecules high in the atmosphere, which causes the light show. Because the phenomenon requires both a magnetic field and a relatively substantial atmosphere, it does not occur on bodies such as the moon, but can be observed near the poles of planets like Jupiter and Saturn. In those cases however, the charged particles come less from the sun and more from the planets' moons.
No comments:
Post a Comment