Photo of the Aurora courtesy of my great friends at http://www.desertskiesphotography.com
They did it the hard way, from the ground in northern Iceland.
I was an Air Force Pilot from 1977 to 1982. In that time, I got to see a lot of very strange things in the sky. But perhaps the most dramatic were the 3 electromagnetic phenomena I will tell you about now: The Northern Lights1, St. Elmo’s Fire, and, oh yeah, that time I was struck by lightning.
The Aurora or Northern Lights
Sometimes we would fly from Northern California to the East Coast in order to pick up some fighters and escort them across the Atlantic. Being KC-135’s, we were their flying gas station. (See my last post.) But if there were no fighters to escort, we would take the Great Circle Route2 and fly very close to the North Pole to get to our European base, RAF Mildenhall. Often, in that northern arc, we would not only see the Northern Lights from afar as someone in the Northern United States might, but actually fly among them.
The aurora is composed of highly charged particles (plasma) interacting with the Earth’s Magnetic field. Millions of tons of these highly charged particles get ejected from our sun on a regular basis. When they fly past our planet, the Earth’s magnetic field captures and directs them to the poles, creating a fantastic light show.
I have said that we “flew among them”. And that is how it sometimes felt. But flying at around 35,000 feet above the ground, it turns out I would have had to have been around ten times higher above the ground to really fly among them. But the Aurora has the appearance of constantly waving and just-out-of-focus sheets of light. You get the feeling that there are many spectra of light that your eyes are just barely not seeing. This makes it hard to get a fix on exactly where they are. So it would seem to me that I was in danger of punching through their luminous curtain at any moment. But scientist have measured3 and the absolute lowest edges of the curtains are around 300,000 feet.
You may recall from an earlier post, flying above 50,000 feet requires the pilot to wear a space suit. The top ceiling for manned aircraft is around 75,000 feet. The International Space Station circles the Earth at around 250 miles.
So the Aurora is an eerie sight. But I’ve never heard of any dangerous interactions between aircraft and these sheets of plasma. So I kept telling myself that, in theory, the aluminum shell of the aircraft should keep all us crew inside safe.
And that’s what we thought about St. Elmo’s Fire.
St. Elmo’s Fire
St. Elmo’s Fire is composed of plasma as well, but the plasma is created here on our home planet. A pointy object, like the top of a ship’s mast, can be a generation point for plasma under certain atmospheric conditions. The novel Moby Dick has a great account of this phenomena on board ship.
Image from http://www.americanflyers.net/aviationlibrary/instrument_flying_handbook/chapter_11.htm
When I have encountered the Fire, it has been a crackly statically looking sheet of small blue lightning shaped sparks across my aircraft cockpit windscreen. I have only encountered it in the Western Pacific. It starts towards the bottom and usually does not even get an inch or two up the window. But let me tell you the story of a fellow pilot who had a different experience.
It was a night, radio-silent refueling mission with the SR-71 Blackbird (see my earlier post) in an undisclosed location in the Western Pacific. The St. Elmo’s Fire had been unremarkable that night until they got into the refueling track and hooked up. Conditions must have been just perfect because the blue sparks were dancing across the cockpit windows like fancy Christmas decorations. No problem though. They just used their instruments to stay on course and they used their radar to keep track of any obstacles in the sky ahead like thunderstorms or other aircraft. All was clear.
It was quite a heavy dose of St. Elmo, which soon became apparent as the Boom Operator reported the glowing crackles were covering his windows. No problem though. We can keep this up.
Then it headed down the boom. The SR-71 pilot, via the boom intercom, reported the tanker all aglow with the Fire. And it was headed down the boom to his ship. No problem though, he reported. We can get our gas. We can still see fine.
The SR-71 has two little panels for the pilot to see out of. And the SR pilot is wearing a space suit. On a good day visibility is a challenge. And now the St. Elmo’s Fire was creeping along his ship and starting to completely cover his small windows.
The SR pilot looked at his fuel levels and decided he’d have enough. If he can’t get the whole recon mission, he can at least get part of it. He called a disconnect from the tanker boom. The Boom Operator disconnected and pulled the boom back and up and the SR-71 eased away from the tanker. But the Fire didn’t get the word! It was still there, connecting the two aircraft, until at about 75 feet separation it SNAPPED with a POP!
No problem. No damage. Just a great story.
Inflight Lightning Strike
My own story about my lightning strike is a little less colorful. I was at Beale AFB on a upgrade ride (co-pilot to pilot) in my tanker on short final for a touch and go. We were about 2 miles from touch down as I glanced down at the end of the runway to help ensure my glide slope was correct. And I saw it.
Several threads of bright lightning lept up at me at a slant from the near end of the runway with dozens of snappy, glowing fingers — and touched my nose! Tingle!!
Well, as we discovered later, it really touched the nose of the aircraft4. But it felt like my nose.
Later that night, as I came through the front door of my house, weary from a long day, my wife greeted me with: “Charlie! Your hair! Why is it so gray today?”
1 The Aurora near the North Pole is called the Aurora Borealis or the Northern Lights. The same phenomena near the South Pole is the Aurora Australis or Southern Lights
2 http://travelcodex.com/2013/03/introduction-using-gcmap/ The Great Circle Route is the shortest distance across our spherical earth
3 “The Northern Lights’ altitudes range from about 50 to 250 miles; different altitudes have different gases, and hence create auroras of different colors. Yellow-green, the most common Northern Lights color, is caused by oxygen molecules 60 miles about the Earth.” That quote was from http://www.isciencetimes.com/articles/6026/20130909/northern-lights-height-aurora-borealis-two-cameras.htm. My calculation is: 50 nautical miles times 6,000 feet per nautical mile = 300,000 feet.
4 That same aircraft, coincidentally, was struck by lightning later that year, blowing off half the wing. The aircraft landed without incident. The aircraft commander (the same one in this story) later said that his controllability checks and the actual landing were almost indistinguishable from a full wing. Fully controllable aircraft with half a wing missing. Boeing makes very good aircraft.
For more amazing photos and the ability to purchase your own posters of “the Aurora from Iceland”, or “the Milky Way from the Utah Desert”, or any number of fantastic images, please visit my friends at desertskiesphotography.com