Northern Lights

Evil Phil

I've been told that in the Artic Circle, when your pretty much right under the lights that make a sound not unlike whale song. Is this true?

Bob the Unlucky Octopus

In a word...no. You might hear whale song, but not from the lights- it'd be the sperm whales making love perhaps? . The lights are caused by radiation interference that don't descend below the middle stratosphere (generally). Unless the mass/density ratio of the gases rivaled something the size of a jetplane and accelerated to such speeds, it's unlikely any such sound would be heard.

Then again, I'm only an armchair astronomer that did a few course units waaaaaaaay back in high school...perhaps someone who's less of an armchair person on the matter could step in here? (/me looks at the Planetarion players...c'mon, one of you planet-phr34ks must know )

Bob the Unlucky Octopus

Lucy_la_morte

Wow, it sounds really interesting. I always thought it was something caused by humans via pollution or something similar.

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It's just a tail, but I'm sort of attached to it.

Lucy la morte.

Chubby

You give humans way too much credit

Hey Bob, what causes the different aurura colors?

Draco

<font face="Verdana, Arial" size="2">Originally posted by Chubby:
Hey Bob, what causes the different aurura colors?</font>

Okay, hazy memory from part of a physics course I did for college 4 years ago:
the lights are cause by radiation hitting atoms in the atmosphere. This releases a photon of light. The colour of the light is determined by how much energy the atom absorbed (and possibly the type of atom). So if alot of energy is absorbed one colour photon is released (say a red photon) and if very little absorbed a different colour released (say a blue photon). So when different strengths of radiation hit the atmosphere it produces the different coloured lights you see.

ThrAx

is it possible to see the aurorae from ireland?

if so wheres the best place to see it?

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Thats ridicilous, nobody beats subzero

Dustaz

I went to Finland a few months ago on a holiday to visit mates. Before i got there all i could ask was 'will the aurora be out'. Everyone said no, wrong time of year, youll never see it.
After almost bleeding killing myself on a snowboard however, i looked up and the sky was on fire. Its a sight that i will never forget, there wasnt a huge display of colours, but it was incredible just the same.
Anyway, point is, it was completly silent, we were out in the middle of nowhere, and there wasnt any wind. The silence made it even more eerie.
Im now working out how i can get to the Antartic to see the southern lights
Thrax, i think the nearest place you can see em is the north of Scotland.

Kolodny

So would there be any sound or just the lights?

[This message has been edited by Kolodny (edited 13-07-2001).]

Evil Phil

The lights have been seen in Ireland, I think every 11 or 13 years there's a Sun Storm which produces particularly powerful lights, so they can be seen from here. It happened this year and apparently you could see them for a few nights but it was cloudy. I've seen them on a trans-atlantic flight and they're amazing. Pity they don't sing though, that would be too cool.

WhiteWashMan

<font face="Verdana, Arial" size="2">Originally posted by Draco:

Originally posted by Chubby:
Hey Bob, what causes the different aurura colors?</font>

Okay, hazy memory from part of a physics course I did for college 4 years ago:
the lights are cause by radiation hitting atoms in the atmosphere. This releases a photon of light. The colour of the light is determined by how much energy the atom absorbed (and possibly the type of atom). So if alot of energy is absorbed one colour photon is released (say a red photon) and if very little absorbed a different colour released (say a blue photon). So when different strengths of radiation hit the atmosphere it produces the different coloured lights you see.

could well be. of the top of my head i would
say that its light being relected at different angles causing the wavelength to change causeing differnt colours. but tht would make it all one colour, so im not sure.
by the way, thats how we get blue and red skies. but yis probably already know that

Victor

<font face="Verdana, Arial" size="2">Originally posted by ThrAx:
is it possible to see the aurorae from ireland? </font>

You will ocassionally see them in Temple Bar on a Saturday night. Oh no, thats areolae. Whoops.

Plural of aurora = auroras

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Kill, kill, kill the laser mice.

Bob the Unlucky Octopus

<font face="Verdana, Arial" size="2">Originally posted by Chubby:
You give humans way too much credit

Hey Bob, what causes the different aurura colors?</font>

What causes the colors to be different is simple- different wavelengths of alpha waves strike the atmosphere at different places. However, the presence and density of particles in the atmosphere can influence how much of the radiation is diffracted into visible light. There is actually a LOT more radiation than is translated into visible light. The reason that the majority of the colors we see are green, is that radiation waves being incrediblys short- they are usually diffracted to shorter wavelengths in the visible light spectrum. The reason we can't see violet or blue that clearly is that these colors don't show up well against a dark sky- green on the other hand, shows up the best This is not however, the same reason (well not quite the same reason) that St. Elmo's fire is usually green. The reason that we get red/blue/violet skies during the day and early evening is that particulate accumulation diffracts visible light with far greater variance than radiation waves. As such, we get to see more colors as the sun goes down (even more than usual if a volcano happened to erupt a few hundred miles away- more particles=nicer color spread )

Hope that was illuminating (Gah, noooooooooooo!!! Bad pun!!)

Bob the Unlucky Octopus