Kristian Birkeland proposed a theory about the auroras that has been widely accepted by scientists. According to him, electrically charged particles ejected from sunspots are captured by Earth's magnetic field and directed along the field lines near the poles. The charged particles follow spiral paths around the lines of force. The incoming particles excite atoms and molecules in the air, ionizing them—stripping them of their non-natural components. This produces the colorful sights associated with the aurora borealis.
aurora borealis.
Aurora australis
Aurora australis. Photo courtesy of Wikimedia, public domain
Birkeland used a simple device to prove his theory: he placed a sphere containing an electromagnet inside a large vacuum chamber, simulating the space around Earth and its magnetic field. He then fired a cloud of electrons at the Earth-imitating sphere to create a luminous phenomenon similar to the aurora borealis. This arrangement is exactly the same as that in a subtle body, as will be explained shortly.
Brak komentarzy:
Prześlij komentarz