Question about a weird thing I saw tonight

[Orrex]

I live about 40 miles north of Pittsburgh Pa. At about 7:50 ET tonight I was outside and happened to notice a jet traveling high enough in the air to be inaudible and visible only as a gray point at the leading end of a long contrail. It was flying almost due west, and the sky was mostly clear except for a few gauzy clouds and not much haze. The setting sun was concealed behind a low bank of clouds.

I'm no good at estimating degrees of arc by sight, so I'll use a crude measurement to give you an idea of how it looked.

Say that the jet itself was 1 unit in length, and the contrail was about 25 units long before dispersing horizontally.

When I first saw the jet, I noticed that it seemed to be following a clear "track" through the thin clouds ahead of it. The "track" looked sort of like what you'd see if you scraped a toothpick through thin layer of syrup on a saucer, and it preceded the jet by about 10 units.

At first I thought that the "track" was static, but then I noticed that it was advancing at a constant rate relative the jet, as though the jet was pushing clouds out of the way far ahead of itself. This persisted for the whole time that I could see the jet.

As I mentioned, the clouds weren't very thick, but thick enough to notice the "track" pretty clearly.

For all I know, this happens every time a jet goes by, but for the life of me I can't remember ever seeing it before. Is this common? What causes it? I was surprised at the distance involved--is it just the force of air ahead of the jet, or is some other factor at work?

MIB's? Chupacabra? Rosebud?

[wli]

1. sounds relatively unusual

I don't have a ready explanation. Maybe it's a military jet traveling at a high altitude and very high speed.

[Geoff R. Casavant]

2. I say coincidence

I've never seen the phenomenon you describe, so since it's a one-time thing, my best guess is that the cloud happened to be breaking up at just the the right rate.

Now, if it happens again, my guess is God likes the pilot.

[Orrex]

3. I'm leaning toward an insidious Weather-Ray myself, but

It's got me baffled, that's for sure. I wish I could describe it better! The "track" was remarkably crisp (admittedly, some thousands of feet in the air, but still sharper than nearby cloud-shifting), to the degree that if it was just a wind phenomenon, that would surprise me more than some bizarro technological explanation.

Is it possible that a small jet could have been traveling ahead of the large, visible one? That would put them pretty close together, and the hypothetical leading jet was leaving no contrail, so I guess that doesn't explain anything...

I'm flummoxed.

[LastDemocratInSC]

4. It was a shadow - I've seen this many times

An airplane and its contrail, flying from west to east around sunset (7:50 PM is near sunset in your area), along a track in which the sun is behind it, will cast a long shadow in the high clouds ahead that appears as a dark track. The shadow will advance along the path of the airplane as the airplane and its contrail move forward.

Airplane and contrail shadows on clouds can be seen at any time of the day. At dawn and at sunset the shadows are cast for long distances, and that is what you saw. During the day, when the sun is higher in the sky, the shadows might be cast onto lower clouds from the airplane and contrail high above. In these cases the shadow will appear as a gray line in the lower clouds paralleling the contrail above. These are equally common.

Airplane and contrail shadows can be observed on any day, when there are any clouds in the atmosphere, in any part of the country. Just go outside and spend some time looking up.

[Orrex]

5. I *still* like the Weather-Ray explanation best

But yours has the unfortunate characteristic of fitting the observed facts!

It makes perfect sense, now that it's pointed out to me. I suppose that I've even seen contrail shadows before, but never at so oblique an angle. Very nifty.

Thanks for the quick answer--now I can sleep.

[greyl]

6. Possibility: shadow or reflection of the fuselage on the clouds

What direction was the jet's motion relative to you and the sun, what direction were you facing, and what angle were the jet and sun at relative to you?
What is your level of certainty that the plane and the clouds were at the same altitude?
Can you place a unit measurement on the thickness of the clouds?
Were the clouds darker or lighter than the sky behind them?
What is your certainty that the "path" was directly aligned with the plane - not off to one side at all, and was ten times the length of the plane?

I'd be absolutely amazed if it was sound waves/air pressure.

edit: crud. too bad it took me so long to compose this thing. Hi LastDemocratInSC. :)