WHAT is going on here?

[owlice]

This image is a crop from a photograph taken in James-Bay, Canada by Michel Tournay (who holds the copyright on the image).

All speculation, guesses, informed replies, and amusing responses welcome.

[Chris Peterson]

All speculation, guesses, informed replies, and amusing responses welcome.

It looks like coronal discharge. I've seen this same effect on high voltage power lines, although never when the sky was so bright (unless this is a long exposure), and never over such a long stretch of lines. It is commonly seen at night around the insulators of lines like this, and can be heard in the day as well.

Do you have any details on the image? As I think about it more, a long exposure of high tension lines might commonly look like this, recording coronal discharge too faint to see with the eye alone.

[owlice]

There is snow on the ground in the picture, and that part of Canada has very low humidity. I cropped out a person in the foreground; the person is not blurry, so I think this is probably not a long exposure.

[Chris Peterson]

There is snow on the ground in the picture, and that part of Canada has very low humidity. I cropped out a person in the foreground; the person is not blurry, so I think this is probably not a long exposure.

Dry air and coronal discharge tend to go together. This image was probably just captured under some unusually perfect set of conditions. I might guess a combination of dry air and dirty ice on the wires.

[Ann]

I always like to understand why objects have the colors they do. In this image power lines look purplish-blue in a wintry night-time landscape. Chris, you said it may be due to a coronal discharge, and I'm not arguing with you. However, can you explain why a coronal discharge might cause power lines to glow purplish-blue? There must be some sort of explanation. I know why hydrogen alpha emission is red - it is because an electron orbiting a proton has been "kicked" into a higher "orbit" by an energetic ultraviolet photon, and when that electron "falls down again" it emits the "extra energy" that was imparted to it as it reached that higher orbit. And the extra energy corresponds to a photon with the red color of emission nebulae.

So what exactly happens when a coronal discharge makes power lines glow purplish-blue?

Ann

[Chris Peterson]

So what exactly happens when a coronal discharge makes power lines glow purplish-blue?

I assume the primary emission lines we are seeing are from nitrogen- the same thing that makes lighting and other electrical arcs through air appear blue to purple. There are also some nice UV lines, so you might get a suntan if you stayed under the wires long enough <g>.

[Beyond]

Ooooooooh. Lavender ice. How nice!!

[NoelC]

Whatever it is, I love that the stuff that happens at extremely high voltages turns the mundane (some might say eyesore) into the beautiful.

We are so blessed with the sense of sight. Never waste a moment of it. Thanks for posting that image, Owlice.

-Noel

[owlice]

Noel, it was my pleasure!

Chris, I was wrong about the exposure; it's a two-minute exposure with a sensitive lens and high ASA setting. I'm surprised the person standing in the foreground (cropped out of this) stood so still as to not be the least bit blurry!

[owlice]

Here's the original image:

I think this is a really cool shot, and I'm surprised Michel was able to stand so still for two minutes!

[wonderboy]

Just why is he holding a light bulb!? Is it because the air is so electrically charged that the lighbulb glows without any mains supply? If it is, its really cool.

Still though, The lines must have been an amazing sight if it was only a 2 minute long exposure.


Paul.

[Chris Peterson]

I think this is a really cool shot, and I'm surprised Michel was able to stand so still for two minutes!

I'm guessing he didn't. The two minute exposure picked up the faintly glowing stuff like the corona and the skyglow, but probably didn't show much of the person in front. The way you usually make an image like this (and there are quite a few APODs like that) is to use a flash or some other light source to paint the foreground unlit objects at the beginning or end of the long exposure used to capture whatever was actually emitting light.

[Chris Peterson]

Just why is he holding a light bulb!? Is it because the air is so electrically charged that the lighbulb glows without any mains supply?

Yes. Fluorescent bulbs readily glow around strong electrical fields. It's a standard trick to wave them near Tesla coils and other field sources and watch them light up.

Still though, The lines must have been an amazing sight if it was only a 2 minute long exposure.

Not necessarily. If it's dark and dry, you can often see corona around high voltage wires. You can hear it as well. It's usually faint, just at the edge of visibility. But a two minute exposure could make that very bright. You only need a one or two minute exposure to bring out all the color of the Milky Way, or to show auroras too faint for the eye.

[michel]

Hi everybody!

Gee you're good!

I'm the guy on the picture of the bluish power lines!

Yes its a coronal effect or the other term is ionization and also known as St-Elmo's fire! (remember the movie : Moby dick!)

I live in James-Bay in the Canadian north, usually very dry!

That night, I wanted to try my new camera and do "Darth Vader" under the 735 000 V power lines with a 8 ft long fluorescent...yep they do light up by themselves!
(actually rubbing them with some wool gloves will make them glow a bit...so it doesn't require a lot of energy to light them up!)

But that night, there was some humidity, and apparently it's a must for the ionization to occur.

Ozone is being produced by those little arcs that are not powerful enough to make a spark

they are like those little plasma lamps that when you touch them, the arcs seems to go find your finger on the small globe

Yes it was loud that night, sounded like tons of shocks!

With the naked eye, we only see a bit of whitish light from the lines, that's why we need to do a long exposure preferably with sensitive lens and ISO settings..

For this one, I used a 28mm f1.4 lens, set the camera for 2 min. at 1000 ASA

As you can see, it was cloudy,,,it might have shown a little star trail if the sky would have been clear!

I asked Hydro Quebec for more info and they said they had seen that only once there and that I was lucky to have seen it twice in the 25 years I've been there!

Yes I was still for the exposure but we can see that the neon light moved a bit...a tad windy!


Here's something from:

http://science.howstuffworks.com/st-elmo-fire1.htm

Causes of St. Elmo's Fire: The Fire That's Not a Fire

Like lightning, St. Elmo's Fire is plasma, or ionized air that emits a glow. But while lightening is the movement of electricity from a charged cloud to the ground, St. Elmo's Fire is simply sparking, something like a shot of electrons into the air. It's a corona discharge, and it occurs when there is a significant imbalance in electrical charge, causing molecules to tear apart, sometimes resulting in a slight hissing sound.
The first step in generating St. Elmo's Fire is a thunderstorm. As you can learn in How Lightning Works, a thunderstorm creates an electrically charged atmosphere. There is a charge difference between the storm clouds and the ground, and this difference creates voltage, or electrical pressure. In between the clouds and the ground, the atoms in the air undergo changes; most important to our discussion, electrons move farther away from protons, creating an environment that allows electrons to move around freely. In other words, the air becomes a good conductor.

Once the air is conducive to the movement of electrons, those electrons continue to increase the distance between their positively charged counterpart, protons. This is ionization, and plasma is simply ionized air. The phenomenon that causes St. Elmo's Fire is a dramatic difference in charge between the air and a charged object, like the mast of a ship, the tip of an airplane wing or the 30-foot steeple of a church -- things we often think of as potential lightning rods.

When the voltage gets high enough, usually around 30,000 volts per centimeter of space, the charged object will discharge its electrical energy [source: Scientific American]. The reason why St. Elmo's Fire occurs most often on pointed objects is that a tapered surface will discharge at a lower voltage level. The tip of a steeple, mast or airplane wing presents something like a condensed surface charge.

When the air molecules tear apart, they emit light. In the case of St. Elmo's Fire, the discharge is continuous -- sometimes lasting several minutes -- and creates a constant glow. The glow is blue because different gasses glow different colors when they become plasmas. Earth's atmosphere has nitrogen and oxygen in it, and this particular combination happens to glow blue.

St. Elmo's Fire is exactly what's happening in neon tubes -- essentially a continuous spark. If Earth's atmosphere were made up of neon, St. Elmo's Fire would glow orange instead of blue. A neon tube is simply St. Elmo's Fire contained in glass. St. Elmo's Fire also behaves something like a plasma globe. One pilot described the phenomenon occurring on the windshield of her small plane while flying through a storm cloud; when she touched the inside of the windshield, blue streaks reached toward the tips of her fingers [source: USA Today].

So the next time you r hear loud sparks from a power line, get your camera gear!

I went again a week after, the air was dry as usual and no effects on the power lines, but if you move with the neon lights during the exposition, we can do some crazy pictures!

Check them out:

http://aurora-borealis.ca/en/galerie2.php?cat=25


enjoy!

Michel

[owlice]

Michel, thank you very much for sharing the picture and for posting! And wow, I had NO idea fluorescent tubes could be so much fun. I think some of these great effects could be used to get a great April 1st image!!

I particularly like this image:

Close the blinds!

---

This one's really cool, too:

Click to view full size image

And... well, a bunch of them! Thanks!!!

[owlice]

Oh, yeah, the power lines all lit up are really cool, too!! As you said: could be hundreds of miles of 'em lit like that!

[michel]

Hi Owlice!

The 2nd picture you just posted is not made with a neon light but actually a small 3-led light you can find at a dollar store.
It didn't light up by itself,,, its battery operated but if you spin it around and walk at the same time during a long exposure, you see the led s lighting up separately!

Michel