What causes the Northern Lights?

Answer 1

Auroras are produced by the collision of charged particles, mostly electrons but also protons and heavier particles, from the magnetosphere, with atoms and molecules of the Earth's upper atmosphere (at altitudes above 80 km). The particles have energies from 1 - 100 keV. Most originate from the sun and arrive at the vicinity of earth in the relatively low energy solar wind. When the trapped magnetic field of the solar wind is favourably oriented (principally southwards) it reconnects with that of the earth and solar particles then enter the magnetosphere and are swept to the magnetotail. Further magnetic reconnection accelerates the particles towards earth.

The collisions in the atmosphere electronically excite atoms and molecules in the upper atmosphere. The excitation energy can be lost by light emission or collisions. Most aurorae are green and red emission from atomic oxygen. Molecular nitrogen and nitrogen ions produce some low level red and very high blue/violet aurorae.

They are usually only visible in the northern areas, im originally from up north and they are beautiful, Now that ive moved to the city i dont see them anymore, but i remember.

They also say if you whistle, theyll dance. Total myth, but its still fun

Answer 2

Charged particles from the solar wind hitting the upper atmosphere cause the northern lights (and southern lights). The Earth's magnetic field steers these particles to the poles, so you only see these lights near the poles. The magnetic poles that is, which are close to but not exactly the same as the geographic poles.

Answer 3

The Aurora Borealis (the Northern Lights), and the Aurora Australis ( the Southern Lights), are both caused by the Earth's magnetosphere interacting with the solar wind.
Charged particles emitted by the Sun are affected by the Earth's magnetic poles. High in our ionosphere, where the air is very rarified, the solar particle excite oxygen and other ions, causing them to glow.
It is this ionic excitement (and therefore, movement) that you can see.

Answer 4

Hey the answers got better at the end!

Campbel is close, but Bobbyp4 hit the nail.

It is the interaction of electrically charged particles in a intense magnetic field (poles) interacting with gases (read neon signs?) that cause the luminosity.

Did you know that a similar fenomenon have been reported every where around the world known as ball lightning? It is frequently mistaken for UFOs. This balls can appear out of nowhere varying in size from 6 in to several feet in diameter. They float in the air and have been reported to go through walls. Some time they speed up and dissapear or just vanish. In some cases they explode with a loud bang. Read this National Geographic Article

http://news.nationalgeographic.com/news/2006/05/060531-ball-lightning.html

Don't you find it a coincidence that UFOs are reported to Glow at night?

Answer 5

The Northern Lights are formed through the interaction of solar winds and the Earth's magnetic field at the poles. The magnetic field at the poles litterally pulls some of the solar wind into the earths atmosphere where it interacts with air molcules, making they glow and sparkle.

Answer 6

The Northern Lights are caused by activity on the sun. Strong magnetic activity is continually taking place on the surface of the sun, and electrons and ions are constantly being thrown out into space.

Answer 7

Northern lights are caused by charged solar-wind particles entering the upper atmosphere.These particles are deflected towards the poles by the earth's magnetic field.As particles spiral down the magnetic lines of force,they bombard gas molecules,causing them to emit coloured light.

Answer 8

Northern lights originate from our sun. During large explosions and flares, huge quantities of solar particles are thrown out of the sun and into deep space. These plasma clouds travel through space with speeds varying from 300 to 1000 kilometers per second.

But even with such speeds (over a million kilometer per hour), it takes these plasma clouds two to three days to reach our planet. When they are closing in on Earth, they are captured by Earth's magnetic field (the magnetosphere) and guided towards Earth's two magnetic poles; the geomagnetic south pole and the geomagnetic north pole.



On their way down towards the geomagnetic poles, the solar particles are stopped by Earth's atmosphere, which acts as an effective shield against these deadly particles.

When the solar particles are stopped by the atmosphere, they collide with the atmospheric gases present, and the collision energy between the solar particle and the gas molecule is emitted as a photon - a light particle. And when you have many such collisions, you have an aurora - lights that may seem to move across the sky.

In order for an observer to actually see the aurora with the naked eye, about a 100 million photons are required.






Coronal Mass Ejection (CME) is another word for the gigantic explosions and flares that occurs on our sun. Click to see a video of such CME's (Courtesy of the ESA/NASA SOHO-project). (MPEG-format)



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Northern lights is a result of our atmosphere shielding against solar particles which would otherwise make our planet uninhabitable. Click to see a video of the aurora. (WMV - Windows Media-format)


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Plasma is the fourth state of matter. Depending on temperature (energy) any matter can exist as:

- Solid (ie ice).
- Liquid (ie water).
- Gas (ie water vapour).
- Plasma (temperature is so great that the molecules are ripped appart and electrically charged).

Answer 9

Charged particles put out by the sun, meeting up with the earth's magnetic field.

Answer 10

Magic