Space Facts: The Northern Lights
What are the Northern Lights (Auroras)?
Northern Lights are green or reddish lights low on the horizon that forms arcs stretching lazily over the sky. Sometimes they will move or shimmer, but no two auroras will ever look alike.
What causes Northern Lights?
Earth is a unique planet made up of many invisible components such as the atmosphere, the poles and even the air. The air we breathe is a mixture of gases comprised mostly of nitrogen and oxygen with a few traces of hydrogen, helium and various compounds. Earth is also surrounded by a magnetic field. Its 'magnet' is deep in the planet's core, and its field lines go into and out of Earth around its magnetic poles.
The Northern Lights are created when energetic electrically charged particles accelerate along the magnetic field lines in the upper atmosphere, where they collide with gas atoms. The collision causes the atoms to give off a light, which is what causes the Northern Lights. Electrons from space can also cause Northern lights. Solar winds carry electrons into the upper levels of the earth's atmosphere where they also collide with gas atoms to create Northern Lights.
What is the scientific name for the Northern Lights?
The North Pole Aurora is called the Aurora Borealis, and the aurora at the South Pole is called the Aurora Australis.
Do astronauts in space see the Auroras?
Astronauts in the space shuttle see the auroras differently than we do on Earth. To them, the auroras seem to cling to Earth's surface. In actuality, the Astronauts are much closer to the Auroras than we are on Earth. The auroras begin about 60 miles above Earth's surface and sub-orbital vehicles fly about 63 miles above Earth's surface.
Source: University of California Observatory