Strange grey line in the sky phenomenon. What the hell?

Question

on a beach in Valencia, Spain in sept 2005. looking east at the horizon at about 6pm. clear blue sky, I noticed a vague grey line, ruler straightand narrow like someone had pencilled it in, touching the horizon and shooting up into the sky at a weird angle, about 80 degrees to the left. it was really indistinct and more visible looking at it periphirally if you get my drift. thought the sun had gotten to me until i noticed other people looking at it including my two friends who saw the same thing. It kinda disappeared high above us in that fuzzy way rainbows do.

Any ideas? this has bugged me for a year now

also, it wasn't like aircraft smoke trails, it had perfectly straight edges and didn't move for at least five minutes until it faded away, kinda like a rainbow does. I'm guessing a rainbow type light refraction kinda thang...

Answer 1

I can think of two possible answers.

First and most likely, I would not rule out an aircraft contrail. A high altitude aircraft can produce a sharp edge contrail that would fade away as the ice crystals that form the faint contrail changes back to a gas phase. This is especially true if you are under a strong high pressure system. The high altitude winds will be light or near calm. The stable enviroment will keep the contrail straight. Therefore, there will be very little mixing and the edges will remain relatively straght until it fades away minutes later. And at a high altitude, a small drift in an aircraft contrail would be difficult to detect under a clear blue sky.

Other clues that high pressure was likely strong that day...

It is September and the skies are clear in the late afternoon and you are along the coast. This tells me that the airmass must be very stable. In other words, the air over your area is sinking over a great depth of the atmosphere...otherwise you will have some type of clouds forming...especially at the low to mid levels by this time of the day. Afternoon and early evening clouds near the coast are usually caused by daytime air rising due the sun heating the surface. The sea breeze will bring the moist marine inland and will increase the chance of cloud formation as this more moist marine air will likely rise upward. However, if high pressure is strong, sinking air will dominate and prevent the air from rising due to the heating of the day. This sinking air can be strong enough to keep the marine layer very shallow or even strong enough to prevent it from forming at all. This can happen due to the fact that a strong high pressure system can even produce a offshore flow that can keep any marine airmass well offshore. This can keep the air clear and cloud free along the coast all day.

Another clue of strong high pressure is likely during this period is that maine air is uaually associated with coastal haze that cab block out the faint line in the sky. With the fact that you have very clear blue skies that you can see the faint line even looking over the ocean horizon would mean that the marine layer is likely not close to the coast. These clues tells me the high pressure is likely stong. And this strong high pressure would keep a high altitude ice crystal contrail when view from the surface relatively strait and sharp for a relatively long time before it finally fades.

My other guess would be space junk falling back into orbit. That occurs more often then most people think. However, most don't form a trail that last more then a few seconds as they tend to burn up fast.

That's my two best guess.

Answer 2

Laser?

Answer 3

Thats wired!!! I don't know, can I see a photo.

Answer 4

a hurricane maybe, that it's soo far away in the open sea?