Tag Archives: illusion

A Cautious Perspective on the Mystery Missile

You may be aware of the mini-controversy  around what was initially thought to be a ‘mystery missile’ launch earlier this week off the California coast.  This clip sums it up:

The official line now seems to be that it wasn’t  a missile at all, but the vapour contrail from a passenger jet, the sunset and viewing angle making the event look like something it wasn’t. Last time I looked, NASA were reported to be supporting that view based on satellite imagery, and a specific aircraft has been correlated with the event.

The incident reminded me that things are indeed not always as they seem, especially  in the sky around sunrise and sunset.  And to illustrate, I’ve dug out a few pictures – all taken in the last three months.

One thing that really struck me in the mystery missile film was the ‘solidity’ and volume of the plume.  Aircraft contrails are more wispy aren’t they?   But then I looked at this picture I took just before sunrise, which includes a contrail every bit as bushy as the one in the film:

Contrails over Surry, UK (Photo: Tim Jones)
Contrails over Surry, UK (Photo: Tim Jones)

Perspective too is a funny thing.  Take a look at this picture I took of a passenger jet near Heathrow Airport in London just as the sun was setting.

Passenger Jet (Photo: Tim Jones)
Passenger Jet (Photo: Tim Jones)

It’s not immediately obvious, to me at least, whether this plane is coming at me or flying away.  There’s a Gestalt Switch moment when the eyes confuse the rear of the fuselage for the nose end.  Things don’t get much clearer when we zoom in:

Passenger Jet (Photo: Tim Jones)
Passenger Jet (Photo: Tim Jones)

A few seconds later and the setting sun catches the plane’s tail, making the direction of flight more obvious.  At a distance, could such a bright reflection isolated to one part of an aircraft be confused with a rocket nozzle – especially if you’d already got the idea in mind?

Sun reflecting off aircraft tail-fin (Photo: Tim Jones)
Sun reflecting off aircraft tail-fin (Photo: Tim Jones)

It’s easy to be fooled by bright objects catching the sun.  Helium filled toy balloons are favourite UFO candidates.  I’ve more than once rushed into the house for camera and binoculars when something fast and bright has appeared in the sky.  The motion of a rising balloon is very smooth, and viewed from the right angle the mystery object can appear to travel horizontally across the sky faster than it really is.  The last one I saw reminded me of an International Space Station (ISS) pass, only in daylight.  Again, one of the issues I have with the mystery missile film is that I can’t tell how fast the missile / aircraft is moving – vertically or horizontally.

Shiny balloons make for great UFOs (Photo: Tim Jones)
Shiny balloons make for great UFOs (Photo: Tim Jones)

Here’s another example of skyward things not being all they at first seem.  To the naked eye, we see a typical multi-engine passenger jet flying at high altitude.

Aircraft contrail illusion (Photo: Tim Jones)
Aircraft contrail illusion (Photo: Tim Jones)

But with the benefit of a telephoto lens, it turns out to be three (presumably military) jets flying in formation:

Three jets in formation, showing contrails (Photo: Tim Jones)
Three jets in formation, showing contrails (Photo: Tim Jones)

Something else that isn’t clear from the mystery missile footage is the absolute and relative position of the helicopter that took the pictures.  Again, perspective can be confusing.  Take a look at this shot I took looking down on a plane in the clouds.  Obviously I took this from the air, right?

Jet plane against clouds (Photo: Tim Jones)
Jet plane against clouds (Photo: Tim Jones)

Wrong.  I was standing in the local park (and it’s not a hilly region) when I took this.  A bird flying into the frame puts some limits on the likely altitude, but it’s still ambiguous if you don’t see the full context:

Jet plane against clouds (Photo: Tim Jones)
Jet plane against clouds (Photo: Tim Jones)

To finish off, here’s a picture I took only a couple of weeks ago from mountains over-looking Los Angeles and the bay area.  It was twilight, and that lump above LA Downtown is Catalina Island.  Perfect missile-spotting conditions.  Maybe I’ll catch the next one.

View over Los Angeles and out to sea (Photo: Tim Jones)
View over Los Angeles and out to sea (Photo: Tim Jones)

UPDATE 13/11/2010

Comprehensive analysis of this event and discussion of previous missile/aircraft contrail confusions here at Contrailscience.com.

Accidental Pepper’s Ghost

This picture of a rare bakelite coffin in the London Science Museum’s plasticity exhibition is also an accidental recreation of the Victorian optical illusion known as Pepper’s Ghost.

Pepper's Ghost effect in a bakelite coffin at science museum
Bakelite coffin at the Plasticity exhibition, London Science Museum (Photo:Tim Jones)

In one version of the illusion, an audience member stands in the coffin on a stage, and the rest of the audience watch as he gradually decays into a dancing skeleton before their eyes.  In that case, the image of a brightly lit skeleton placed in a pit in front of the stage is reflected by an angled sheet of glass placed between the audience and coffin.

On similar lines, a less elaborate experiment you can try yourself with a sheet of plane glass and two tea-lights is described in this piece from the Naked Scientists.

I’ve had this picture for a while, and only noticed the Pepper’s Ghost effect when I pushed the shadow enhance slider on iPhoto.  Quite scary seeing oneself encoffined.  Good job I’m not superstitious….

Appearances Can Be Deceptive

I keep running into this demonstration of how strange our brains can be, so thought I’d have a go myself.

Have a look at the inverted face below.  Upside down, but still pretty cute eh?

Cute
Cute

Now look at the next picture where she’s turned the right way round – yuk!

But it’s exactly the same picture just inverted.  Our brains somehow pick out the individual elements of the face and reconstruct them as we normally expect to see them – I guess?   Personally, I can’t see a glum person in the top picture without turning my head to a degree – I’ve just discovered – not so good for my neck.

Not so cute.  Well, not so happy anyhow.
Not so cute. Well, not so happy anyhow.

This simple example was made by cutting, rotating, and pasting the mouth of the girl in the painting.

I saw something like this a couple of years back at the Exploratorium Science Centre in San Francisco.    The most recent demonstration I’ve seen was at the Weird Science event here in London earlier this month, where Richard Wiseman had us all in hysterics with a doctored picture of Margaret Thatcher.  That was doubly strange, as: (a) he’d turned the eyes round as well (which is the correct thing to do, but my painting struggles because of the hair) and, (b) rotated the image slowly, which revealed there is a certain point where the brain clicks over to seeing the ‘new’ image – the gestalt switch moment.

The Exploratorium exhibition also included so-called hybrid images of faces that change expression depending on how near or far you stand from them.  The effect still works very well on a computer screen, but you need to stand a long way back.

Not entirely sure how the brain processes compare for the two types of phenomena, but I find the ‘switch’ is more gradual with the hybrid images.   In deference to copyright I’ll not share the snaps I took, but you can find something very similar at the ‘Hybrid Images’ website owned by Dr.Aude Olivia, Dept. of Brain and Cognitive Sciences at MIT.

See Sophie smile and scowl and smile and scowl and smile
See Sophie smile and scowl and smile and scowl and smile