Alert — Aurora (Northern Lights) Possible Tonight

There was a big solar flare on Monday, which as often happens created a flash of X-rays (travel time to Earth 8.5 minutes), a blast of high speed protons and electrons (travel time minutes to hours), and a “Coronal Mass Ejection” (CME) of slower subatomic particles (travel time 1 to 3 days.) It’s the CME … Read more

Watch for Auroras

Those of you who remember my post on how to keep track of opportunities to see northern (and southern) lights will be impressed by this image from . The top plot shows the number of X-rays (high-energy photons [particles of light]) coming from the sun, and that huge spike in the middle of the plot indicates … Read more

Ongoing Chance of Northern (or Southern) Lights

As forecast, the cloud of particles from Friday’s solar flare (the “coronal mass emission”, or “CME”) arrived at our planet a few hours after my last post, early in the morning New York time. If you’d like to know how I knew that it had reached Earth, and how I know what’s going on now, scroll … Read more

Why did so few people see Auroras on Friday night?

Why did so few people see auroras on Friday night, after all the media hype? You can see one of two reasons in the data. As I explained in my last post, you can read what happened in the data shown in the Satellite Environment Plot from this website (warning — they’re going to make … Read more

Auroras — Quantum Physics in the Sky — Tonight?

Maybe. If we collectively, and you personally, are lucky, then maybe you might see auroras — quantum physics in the sky — tonight.

Before I tell you about the science, I’m going to tell you where to get accurate information, and where not to get it; and then I’m going to give you a rough idea of what auroras are. It will be rough because it’s complicated and it would take more time than I have today, and it also will be rough because auroras are still only partly understood.

Bad Information

First though — as usual, do NOT get your information from the mainstream media, or even the media that ought to be scientifically literate but isn’t. I’ve seen a ton of misinformation already about timing, location, and where to look. For instance, here’s a map from AccuWeather, telling you who is likely to be able to see the auroras.

Don't believe this map by AccuWeather.  Oh, sure, they know something about clouds.  But auroras, not much.
Don’t believe this map by AccuWeather. Oh, sure, they know something about clouds. But auroras, not much.

See that line below which it says “not visible”? This implies that there’s a nice sharp geographical line between those who can’t possibly see it and those who will definitely see it if the sky is clear. Nothing could be further than the truth. No one knows where that line will lie tonight, and besides, it won’t be a nice smooth curve. There could be auroras visible in New Mexico, and none in Maine… not because it’s cloudy, but because the start time of the aurora can’t be predicted, and because its strength and location will change over time. If you’re north of that line, you may see nothing, and if you’re south of it you still might see something.  (Accuweather also says that you’ll see it first in the northeast and then in the midwest.  Not necessarily.  It may become visible across the U.S. all at the same time.  Or it may be seen out west but not in the east, or vice versa.)

Auroras aren’t like solar or lunar eclipses, absolutely predictable as to when they’ll happen and who can see them. They aren’t even like comets, which behave unpredictably but at least have predictable orbits. (Remember Comet ISON? It arrived exactly when expected, but evaporated and disintegrated under the Sun’s intense stare.) Auroras are more like weather — and predictions of auroras are more like predictions of rain, only in some ways worse. An aurora is a dynamic, ever-changing phenomenon, and to predict where and when it can be seen is not much more than educated guesswork. No prediction of an aurora sighting is EVER a guarantee. Nor is the absence of an aurora prediction a guarantee one can’t be seen; occasionally they appear unexpectedly.  That said, the best chance of seeing one further away from the poles than usual is a couple of days after a major solar flare — and we had one a couple of days ago.

Good Information and How to Use it

If you want accurate information about auroras, you want to get it from the Space Weather Prediction Center, click here for their main webpage. Look at the colorful graph on the lower left of that webpage, the “Satellite Environment Plot”. Here’s an example of that plot taken from earlier today:

The "Satellite Environment Plot" from earlier today; focus your attention on the two lower charts, the one with the red and blue wiggly lines (GOES Hp) and on the one with the bars (Kp Index).  How to use them is explained in the text.
The “Satellite Environment Plot” from earlier today; focus your attention on the two lower charts, the one with the red and blue wiggly lines (GOES Hp) and on the one with the bars (Kp Index). How to use them is explained in the text.

There’s a LOT of data on that plot, but for lack of time let me cut to the chase. The most important information is on the bottom two charts.

Read more

Northern Lights Tonight?

[UPDATE, midnight New York time: the cloud of particles from the solar flare arrived a few hours ago, but it didn’t impact the earth’s magnetic field quite as hard as the best-guess forecast. (Remember the probability of a geomagnetic storm was only 60%; i.e. the probability of no storm was 40%.) Right now, the auroras are likely visible in Canada but probably not in the US. This could change, but don’t get your hopes up too high; we may have to wait for the next solar flare.]

I’ve been sidelined with computer troubles and non-science activities, so first, a belated thanks to everyone who left a thoughtful comment after Monday’s post and question about communicating science to the public.  I appreciate hearing your views, especially from readers with a diversity of backgrounds!

Now, many of you may have heard that there is a forecast of northern (and southern) lights, also known as auroras, tonight.  What you’ve heard is correct: today’s NOAA space-weather forecast, from,  says

VI.  Geomagnetic Activity Probabilities 13 Apr-15 Apr
A.  Middle Latitudes
Active                30/30/15
Minor Storm           35/45/05
Major-severe storm    10/15/01
B.  High Latitudes
Active                10/15/15
Minor Storm           20/25/20
Major-severe storm    60/35/20

i.e. it shows that even in mid-latitudes (meaning northern US and southern Canada, and northern Europe, along perhaps with parts of Australia and New Zealand [?]) they are estimating a 35%-45% probability of a minor `geomagnetic storm’ tonight, with a 10-15% probability of a major storm… and a geomagnetic storm, which literally means a lot of activity in the earth’s magnetic field, generally leads to auroras further away from the north and south pole than usual.

Read more

%d bloggers like this: