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Q & A: Northern Lights

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Most recent answer: 06/04/2011
Q:
Hi Courtney here Just wanted to know about the northern lights Any info about them is fine im just fascinated by them Thank you From courtney :)
- Courtney (age 14)
Australia
A:
Hi Courtney.  The lights are caused by charged particles entering the earth's atmosphere.   These particles are part of the 'solar wind', that is, material which is ejected from the sun.  The lights, called Aurorae Borealis in the northern hemisphere and Aurora Australis in the southern hemisphere are produced by the collision of charged particles with atoms high up in the atmosphere.  The earth's magnetic field tends to guide these particles preferentially to the north and south poles, so they are most often seen in northern and southern polar skies.  Here is a web site that has much more information: 
   
LeeH

(published on 06/15/2009)

Follow-Up #1: spiraling in a magnetic field

Q:
I dont think even you can answer this..but here goes, how can your answer:  "Charged particles from solar wind spiral in towards Earth along the geomagnetic field lines and create the Aurora." be correct ? There are both northern and southern aurora..... If the magnetic lines dive into the earth at the north pole... Only, and return/exit at the south pole.... then there would only be northern lights.... How then, is the phenomenon of having both explained... Thank you, Stan
- Stanley laporta (age Old)
Trumbull, Ct usa
A:
I've been unable to find the particular answer you were quoting, so I've marked this as a follow-up to another closely related question.

Changing the sign of the magnetic field only changes which sign of charge spirals clockwise and which spirals counterclockwise.  The motion along the field lines is unaffected. These are magnetic, not electric, fields!


So yes, there are both northern and southern lights.


Mike W.

update: aha, I found the one you're quoting: . Same answer.


(published on 05/30/2011)

Follow-Up #2: magnetic spirals

Q:
Good morning Mike. Thank you for trying... It's a tough one to grasp. It's not your fault. Some things have answers and some don't... Thanks again, Stan
- Stanley LaPorta (age Old)
Trumbull Ct usa
A:
I'm puzzled by your remarks. The force on a particle with charge q moving with velocity v caused by a magnetic field B  is proportional to qvxB. That means that there's no force along the magnetic force line direction. The force is at right angles to that. Changing the sign of B still leaves the particle circling about the field line, just circling the opposite way. That has no effect on its approach to the earth.

As the old phrase goes, what part of "no" don't you understand?

Mike W.



(published on 06/01/2011)

Follow-Up #3: no disrespect

Q:
Good morning Mike. I did not mean any disrespect. You took it differently than I meant you to. I too know the science. It just that it's not working in this instance. I won't bore you. Just thought there was something new on it. Watch a video clip of an eruption of plasma on the surface of the sun. Watch what happens to the plasma as it try's to move away from the surface. Honestly, thank you.
- Stanley LaPorta
A:
Stanley- Sorry, whenever I hear that line, I think of Jon Stewart doing one of his standard shticks. Cracks me up.

 No disrespect.

Mike W.

(published on 06/04/2011)

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