Rectangle In The Sky Over North London

Victory

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#1
I live near a Heathrow flight path.
Tonight, about 11pm, a flashing whiteish yellowish light moved from West to East across the sky.
Nothing unusual at all...just another plane leaving Heathrow.

But...underneath it, moving at the same speed, was a rectangle shape.
The sides were only about 15% longer than the ends, so it was almost a square shape.
It was odd in that at the same time it was made up of light cloud, of the type that is in the sky, yet seemed to be an opening in the cloud.

Obviously I thought it was caused by the lights of the plane, but it disappeared whilst the lights were still flashing, before the lights became obscured by the roof of a building.

I am very much leaning towards a "trick of the light", but nonetheless it was not something I have ever seen before, and really stopped me in my tracks.
 

EnolaGaia

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#2
... But...underneath it, moving at the same speed, was a rectangle shape.
The sides were only about 15% longer than the ends, so it was almost a square shape.
It was odd in that at the same time it was made up of light cloud, of the type that is in the sky, yet seemed to be an opening in the cloud ...
I'm having trouble parsing this description of the incident ...

Could you see the silhouette of the airplane?

Could you tell where on the airplane the flashing light was located? (underbelly? tail?)

Did the rectangular shape align with the airplane, or was it skewed relative to the aircraft's long axis / flight path?

Did you see the rectangular shape continuously, or was it intermittently visible only when the plane's light flashed?
 

Victory

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#3
@EnolaGaia

I could not see a silhouette of the plane.

I could not tell where the flashing light was located, but my instinct said "plane." It was a flashing white/yellow light...the flashes were at regular intervals of about one per two seconds.
It was consistent with the type seen on a plane's tail tip.

The rectangular shape was I believe aligned with the aircraft fuselage.

I saw the rectangular shape continually for three and a half to four seconds, then it faded rapidly over the course of about half a second, but I could still see the flashing light. This then passed over a building and out of my field of vision.

I am not suggesting that the flashing light was of alien origin.
But the rectangular shape invoked in me feelings of awe...and wonder.
Because as crazy as this sounds, it seemed to be made of cloud but of a lesser density than the surrounding cloud in the sky.
The sky was not thick with cloud, but had clouds in it.
Also the rectangle shape had straight sides, not wavy in any way.
 
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EnolaGaia

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#4
Thanks for the clarifications. As Murphy would dictate, this only leads to more questions ...

If the rectangular shape was "fully" visible for a maximum of 4 seconds, and it was visibly "fading" rapidly (I'll call it a second, even though you stated half a second), this suggests a total elapsed viewing period of circa 5 seconds for the rectangle.

If the flashing light had a 2-second flash interval, this would mean you observed 2 (and possibly 3 at the very most) flashes while the rectangular shape was discernible at all.

Does this seem right?

Did you see any other lights (flashing or not) associated with the single flashing light? If so, please describe them.

Did you hear any sound indicative of an aircraft associated with this light? If so, what type(s) of aircraft was this sound consistent with?

Something I should have asked earlier ... Was the rectangular shape visible when you first noticed (or at least first locked onto) the flashing light? In other words ... My understanding is that you saw the rectangle fade / disappear. Did you see it appear earlier, or was it always visible?

Was it the flashing light that caught your attention / notice and you zeroed in on it, OR were you casually surveying the sky and happened to notice the flashing light within your field of view?

You mentioned the flashing light was "yellowish". Modern marker flashers are bright white. A yellowish cast would suggest an intervening haze or very thin cloud layer if this had been a commercial airliner or transport passing overhead.

Speaking of "overhead" ... What was the approximate angle of elevation for this thing relative to you? Was it (e.g.) directly overhead? Down near the horizon? Some approximate angle in between the zenith and the horizon?
 

henry

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#5
there was a great FT letter a number of years ago about a large translucent rectangle observed in the sky over one of the thames bridges by multiple pedestrians
 

Victory

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#6
@EnolaGaia

Yes, about four seconds of seeing the rectangle, it faded over about half a second, possibly three quarters of a second.
After it had faded it had completely disappeared.

Yes, I saw the flashing light flash two times whilst the rectangle was visible, then one further time just as the rectangle had almost completely faded.

I saw no other lights.

I heard no sound.

The rectangle was visible simultaneous with me seeing the flashing light.
It was always visible.

I did not see any type of "searchlight" effect which might have been caused by the plane shining a powerful light below it to search for something on the ground.

I saw the flashing light and rectangle because I was casually surveying the sky as I walked home.
I was looking straight ahead but slightly upwards and saw the light and rectangle in my field of vision.
The shorter part of the rectangle was horizontal to what I took to be the tail of the plane, the longer sides parallel to what I took to be the fuselage.

The flashing light was not pure white...it was in my view "off white" but had a small yellowish component...I took it at the time to be a plane marker.

Angle of elevation was 40-45 degrees.

I was walking at a slow pace, heading North.
The light and rectangle were ahead of me, moving from West to East.

My instinct told me it was a lane flying quite low, as the light was moving at a pace which suggested that.
The light moved across the sky fairly "quickly", as lights on low flying planes do.
It was in straight path, not jerky or circular.
From past experience, when seeing commercial jet airliners fly, they might very well be flying at many hundreds of miles per hour but because they are at quite an altitude, they appear "slow".

This light was not that, it moved faster.

Where I live, I often see planes queuing up to get into Heathrow Airport, to the East of my block of flats, flying from the East, on to land at Heathrow, which is to the South West of where I live.

There is also a small aerodrome about five miles away, plus RAFs Northwood and Northolt are 6 or so miles away.

It is not unusual to see military helicopters fly past...say about once per fortnight.

Police helicopters also circle for training purposes, but this was not consistent with those neither in visual simularity and especially not audibly...as those are loud at night.

So I would guess at a light aircraft or private jet?
 

eburacum

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#7
It may have been the landing lights illuminating a thin layer of cloud underneath the 'plane. Similar effects occur when a 'plane's shadow falls onto thin cloud in daylight. Either the thin cloud layer ran out, or the 'plane switched its landing lights off.
 
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EnolaGaia

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#8
Thanks for the additional info and clarifications.

It may have been the landing lights illuminating a thin layer of cloud underneath the 'plane. Similar effects occur when a plane's shadow falls onto thin cloud in daylight. Either the thin cloud layer ran out, or the plane switched its landing lights off.
This was the sort of "back-projection from above a haze / cloud layer" scenario that first occurred to me.

The landing lights hypothesis is something I've (personally) ruled out. Landing lights are aimed forward - out front of the aircraft. Any refracted or dimly seen landing light illumination wouldn't spatially correlate with a flashing marker light, which would be located on the underbelly or tail of an airplane.

I'm leaning toward ruling out any sizable winged aircraft (e.g., an airliner, commercial transport, etc.), because no other lights were visible. There should have been at least one additional (non-flashing) marker light visible.

One of the only aircraft-related scenarios that seem to fit the observation is a heavy-duty (e.g., sky crane) helicopter airlifting a large rectangular translucent (or perhaps meshwork) object. This might explain the flashing light being spatially correlated with the rectangle (as a marker light on the copter's underside shining through the under-slung object ). It would also imply the overflight was at a relatively low altitude, which would explain the apparently speedy movement as viewed from the ground.

Another long shot possibility might be illumination from a brightly lit landing gear well, which would be in the same relative vicinity as a belly marker light. However, this begs the question of why such illumination would be coming from only one of probably three wheel wells. Some landing gear have spotlights mounted on them, so I suppose you could get a single one shining if the landing gear upon which it was mounted was the only one in the process of deploying or retracting. Odd, but conceivable ...

Frankly, I'm starting to like an entirely different angle (pun intended) ... This is the possibility there wasn't an aircraft at all, and the composite mystery imagery was front-projected upward onto a low-lying layer of haze or cloud.
 

eburacum

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#9
The curious thing about this description is that the 'rectangle' was "made up of light cloud, of the type that is in the sky, yet seemed to be an opening in the cloud", and also "seemed to be made of cloud but of a lesser density than the surrounding cloud in the sky".

That makes it sound more like a shadow than anything. But at 11pm there would be no sunlight to cast a shadow. How about moonlight?
 

eburacum

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#10
Here's a video of low-flying planes casting shadows on clouds. Admittedly, this is in sunlight, but the cloud shadows make some strange shapes at times.

The Moon was just past full on Wednesday night.
 

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#11
I hadn't seriously considered a shadow-based explanation because Victory described the rectangle as if it were just that - a well-defined rectangular shape or form.

I can't figure out how a discrete rectangle (as opposed to an entire plane silhouette) could be cast as a shadow. This implies any rectangle-shadow was a truncated version or segment of the plane's larger / overall shadow, and I can't come up with an explanation for how that could occur. The main sticking point is that the rectangular shape / form was visible continuously, and wasn't dependent on illumination from the flashing light. This rules out the flasher as a secondary light source of the sort necessary to cast a truncated or partial shadow (under certain scenarios).
 

eburacum

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#14
I'm fairly sure this was a moon-shadow of some sort. The plane casting the shadow may have been banking, and this would make the shadow of the wings difficult to see; also the penumbra effect could have blurred the outline, removing the outlines of the engines and tail. But this wouldn't explain the apparent sharpness of the rectangle. I would note, however, that the night sky is not very bright, even in moonlight, so the observer's eye may have been over-compensating.

Another possibility is a contrail shadow - aircraft condensation trails cast straight-edged shadows, and if the shadow was moving across a thin strip of cloud oriented in the opposite direction (perhaps another, older contrail) the resulting shadow could have looked rectangular.
 

Victory

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#16
Thank you for all your suggestions, because I really baffled by this.
To answer them:

@eburacum

Am not convinced it was a shadow cast by landing lights.
The plane was moving West to East. So that is away from Heathrow, Northwood, Northolt and Elstree.
It was not landing, so why would the landing lights be on?
Plus the rectangle had very straight sides.

I also believe that the moon was to the left and slightly behind me, to the West, so it is possible that it cast a shadow of the fuselage but the moon was quite low in the sky.

Contrail shadow is a possibility, but would that explain the rectangle moving, and it's rapid fading?

@feinman

No, the rectangle was not formed out of a thick cloud (see below).

@EnolaGaia

I too am struct by the very straighness of the rectangle's sides.

I must clarify that they were NOT definite lines, rather that the borders of the shape were very straight and delineated.

The best approximation I can give is this photo.
I did not take this photo, it is not of the sky in my area, but it is the best match I can find for the type of conditions in the sky that I saw last week.
I have used the Exposure function on my Mac Preview Software to "Light" a rectangle shape to give a reasonable approximation of the way the rectangle appeared to me, as a "lighter" area of sky, set against the way the rest of the sky appeared.

The rectangle was not formed by the borders of clouds, which were curved and indeed in places overlapped the borders of the rectangle.


Rectangle image.jpg

Please forgive my basic drawing skills, or lack of, but this handrawn sketch shows where I was in relation to my block of flats (which are the building on the right of the sketch) when I saw the flashign light and rectangle.
The "three" lights represent the places where the light flashed.
There was just one flashing light, moving West to East.
The three rectangles similarly, represent stages of the rectangle's path across the sky, though it is vital to stress that I saw it CONSTANTLY, not at intervals.

Rectangle diagram.jpg
 
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EnolaGaia

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#17
Thanks for the additional details and clarifications, Victory.

I initially interpreted your description to mean that the rectangle surrounded ( / overlaid / framed / ... ) the flashing light.

Your sketch indicates the flashing light appeared outside / to the side of the rectangular shape. Is that the case?
 

Victory

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#18
@EnolaGaia

The rectangle was below the flashing light, and centred slightly ahead of it.

They moved at the same speed relative to each other, in the same direction.

It occurred to me that it is possible that the light, if if was from a plane...was part of a plane or other craft which was pursuing or investigating the rectangle.
 

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#19
Given the scene's / area's layout illustrated in your sketch ...

Is there any location from your vantage point (that night) lying to the north (and possibly offset to either side - i.e., west or east) where there would have been construction work or other heavy equipment usage occurring? Or possibly a railroad line that runs east-west?

Such a location need not be close to your observational vantage point - it could have been at some distance from you in a northerly direction.
 

eburacum

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#20
Ah, so the rectangle was brighter than the surrounding sky. That seems to rule out shadows, and suggests a spotlight of some sort. An aircraft with, or followed by, a spot-light is unusual, but not necessarily alien.
 

Victory

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#21
EnolaGaia

No. There is a railway line to the West, but at that time of night there are just passenger trains running on it.
The nearest construction site is a mile to the north, new apartment blocks being built, but at that time of night no work is carried out, and it is not lit up as it is in a residential area and subject to strict controls on work hours.

eburacum

This may read like a contradiction, but it is not meant to be so.
The rectangle appeared not as if it was brighter than the surrounding sky, but appeared as if it had less darkness....in the sense of if there was a dirty window, and you wiped a rectangular section with a cloth, not so much as to clean away all the dirt, but enough to alleviate a surface layer of dirt...that sort of effect.

I do not believe it was a spotlight from above or below, because of the sheer straight edges it had.
There was no hint whatsoever of a beam of light in any direction.
I have seen a few spotlights before in London, onto cloud cover, and this looked very different.
 
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eburacum

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#22
My suggestion is that this was a spotlight or landing light shining from a plane or helicopter onto a thin, narrow band of cloud. Perhaps a contrail or a smoke trail of some sort. The band of cloud would simply look lighter than its surroundings, and would look rectangular because it presumably had straight edges. Because this rectangle was brighter than the surroundings, it would naturally appear to have 'less darkness'.

If the spotlight itself was concealed from your view, and if the air was clear (apart from the contrail or smoke band), the only illuminance you would see would be coming from the rectangle itself. A rare set of circumstances, and not one that would be easy to identify in the brief time you saw it.
Here is a rough sketch of what might have been happening.
 

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#25
i was thinking more about the validity of an aircraft bathing a huge area of north london in light, as opposed to a spotlight
 
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EnolaGaia

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#26
My suggestion is that this was a spotlight or landing light shining from a plane or helicopter onto a thin, narrow band of cloud. ...

If the spotlight itself was concealed from your view, and if the air was clear (apart from the contrail or smoke band), the only illuminance you would see would be coming from the rectangle itself. ...
Good summary, and a good illustration.

I'd considered this sort of explanation but shuffled it downward in the stack, mainly because one still has to account for the flashing white / yellowish light in a stable relative position keeping pace with the rectangle.

The only explanation accommodating both the rectangle and the flasher on a single moving airplane would entail the airplane being banked / tilted so as to expose an alert / beacon flasher on the dorsal or ventral surface of the plane.

Landing lights are mounted / deployed on the lower (ventral) half of a plane. If an airplane were banked "away" from the observer (exposing this ventral side) the landing lights themselves would likely be visible as themselves, or at least insert fuzzy point sources within the rectangle they were projecting onto the intervening cloud / haze.

If an airplane were banked "toward" the observer (exposing the dorsal side) this issue is resolved, but it still leaves an issue relating to the plane being banked / tilted at all ...

Why didn't Victory see the red and green or blue side beacons mounted on the wings - both of which should have been visible with an airplane in a banked orientation?
 

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#27
It only needs to be a landing light illuminating a layer of cloud just under the plane, but spotlights are not unknown. I remember a helicopter near our house searching the river with a spotlight.
 

EnolaGaia

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#28
Having said that ...

IMHO the notion of a helicopter with only a single white / yellowish flasher shining a spotlight away from the observer onto a thin band of cloud / haze is still very much in play.
 

EnolaGaia

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#29
It only needs to be a landing light illuminating a layer of cloud just under the plane, but spotlights are not unknown. I remember a helicopter near our house searching the river with a spotlight.
Agreed ... You posted before I'd finished writing my subsequent post.
 

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#30
how could a spotlight/searchlight or other illumination from an aircraft produce the moving rectilinear effect observed ...

I did not see any type of "searchlight" effect which might have been caused by the plane shining a powerful light below it to search for something on the ground.

could the aircraft have been carrying something, illuminated for safety/manoeuvring ?
 
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