Calling Bad Astronomer: aurora borealis question.

Tripler · February 10, 2003, 3:55am

I’ll get straight to the point: Is there any certifiable way to predict when the aurora borealis will appear?

The story: I was driving home tonight from Bismarck, about an hour and a half drive. Just south of Max (35 miles from town), I looked and saw what I thought was the glow of headlights from the north. Weird thing was, they were green! And they kept moving. About a half a breath later I realised I was looking at the aurora borealis. Peronally hailing from Northern New Jersey, I was under the impression that: A) They only come out during the wintertime, and B) You can only see them from the Northern Tier.

I know they can come in different colors. I also found out from a search of the SDMB that you can apparently see them as far south as Tuscon, AZ. I also found that you can get a forecast of solar activity from the government.

So, is it really all that possible to predict when, where, and what color they’re gonna be?

Tripler
Last time I saw them, I was at a toga party in May. No, I wasn’t drunk.

Finagle · February 10, 2003, 5:52am

Check out www.spaceweather.com. They keep track of solar activity and give estimates of how likely it is that there will be activity.

The northern lights are not limited to winter time, although the nights are longer and often clearer so maybe they’re more frequently seen then.

As for predicting where the aurora will be visible, when, and what color – it seems to be a very approximate art. We can observe coronal holes and solar mass ejections but apparently can’t tell precisely where the ejected particles are heading or how fast.

rowrrbazzle · February 10, 2003, 9:46pm

www.spacew.com also has recent sighting reports.

From http://science.nasa.gov/headlines/y2001/ast26oct_1.htm:

Geomagnetic storms erupt when solar wind gusts or coronal mass ejections (CMEs) hit Earth’s magnetosphere – a magnetic bubble around our planet that protects us from the relentless solar wind. The magnetosphere is filled with electrons and protons. Normally these particles are trapped by lines of force (so-called “magnetic bottles”) that prevent them from escaping to space or descending to the planet below.

“When a CME hits the magnetosphere,” explains Tony Lui, “the impact knocks loose some of those trapped particles. They rain down on Earth’s atmosphere and cause the air to glow where they hit.” Lui is a space physicist at the Johns Hopkins University Applied Physics Lab.

“Precipitating particles mostly follow magnetic field lines that lead to Earth’s poles,” he added. “The auroral ovals (circular regions of auroral light around the magnetic poles) expand during magnetic storms.” Sometimes they grow so large that people at middle latitudes – like North Carolinans – can see the light.

Such widespread storms are usually nurtured by what scientists call “B[sub]z[/sub]” (pronounced “Bee sub Zee”) – in other words, the component of the interplanetary magnetic field (IMF) that lies along Earth’s magnetic axis. At the magnetopause, the part of our planet’s magnetosphere that fends off the solar wind, Earth’s magnetic field points north. If the IMF tilts south (i.e., B[sub]z[/sub] becomes large and negative) it can partially cancel Earth’s magnetic field at the point of contact.

So we can get some advance warning (hours, I think) if we monitor B[sub]z[/sub]. But it’s not foolproof.

That page also says we tend to get more and brighter displays around the beginning of spring and autumn.

The_Bad_Astronomer · February 10, 2003, 10:01pm

Right. Like rainfall, you can predict when you get an aurora and maybe how strong it will be, but it’s not practical to predict exactly how strong or where it will be.

C_K_Dexter_Haven · February 10, 2003, 10:37pm

Walt Kelly:

Mac_Guffin · February 11, 2003, 12:01am

A) Dude, it is still winter here. I thought the sub zero temps would have been a clue.

B) This IS the Northern Tier. Any further north and you are in Canada.

I saw those lights as well, way over here in Fargo. I have seen many brilliant displays here, some even in summer.

Yeesh. Max, North Dakota. I have family out there. Desolate wasteland.

Fretful_Porpentine · February 11, 2003, 12:22am

Who roars a roar for Nora,
Charming Nora in the night;
For she has seen Aurora
Borialis burning bright.
[/quote]

[/quote]

Hmm, can’t find the Pogo books at the moment, but the version I remember is slightly more euphonious:

As a side note, I’ve been toying with the idea of going to southern Alaska in early May. Would I have a shot at seeing them, or is that too close to summer? (My name is Nora, if that helps at all :))

Tripler · February 11, 2003, 1:39am

[list=1]
[li]“Wasteland”! And you wonder why I bitch about Minot.[/li][li]I thought it was weird when I saw them in May.[/li][/list=1]

I thank y’all for the help in the sites. The only thing I’m left with is this: Is color a part of latitude? I’ve heard of green, blue, and even read auroroa borealis. I can only theorize it’s a function of which angle the solar wind strikes the magnetosphere. . .

Tripler
And particlewill, when the hell are you coming to Minot for a Doper Gittogether?!?

Tripler · February 11, 2003, 2:02am

Make that “red” in the aurora borealis.

I’m a moron, no matter how many times I preview. . .

Tripler
But colors, are they predictable?

SnugTheJoiner · February 11, 2003, 8:05am

Fretful Porpentine:

Got my handy POGO book right here. And the song goes:

O roar a roar for Nora,
Nora Alice in the night.
For she has seen Aurora
Borealis burning bright.
A furore for our Nora!
And applaud Aurora seen!
Where, throughout the Summer, has
Our Borealis been?

IMHO, Walt Kelly had a gift for twisting and remolding the English language unlike anyone since James Joyce. He could have been a great writer like Joyce, but instead he decided to use his talent to make people happy.