15-seconds of fame


Today on ten-minutes’ notice, I was interviewed for a BBC science programme.

Unexpectedly, I was asked to comment on an article in a British newspaper with the intriguing title:

Passenger’s amazing photo captures moment her plane flew directly over a ‘RAINBOW’

A good rule of thumb is that one should be on one’s guard whenever a copywriter uses the word, amazing. This was no exception. The picture was not of a rainbow but was the result of stress polarization in a birefringent aircraft widow—a phenomenon previously treated in this blog. 

The explanation and picture from that earlier posting is:

The aircraft window, itself, can show some interesting features. The stressed plastic of the window is birefringent and so produces colours when seen with polarized light. The light from most scenes is not strongly polarized, but a reflection from a body of water is, so the colours seen here are a consequence of both the reflection (from, in this case, Georgia Strait) and the aircraft window.

To me, what was particularly interesting is that the person who took the picture in the article, Melissa Rensen from London, Ontario, had come close to guessing what caused the colour in her picture: She speculated that it was the result of “the polarized window on the plane.” (The window isn’t polarized, light is polarized, but the window is birefringent). However, another photographer then misled her by suggesting that it couldn’t be in the window by pointing “out that the rainbow was beneath the clouds.” That other photographer was wrong. 

The colours seen require three things: polarized light (this comes from sunlight reflected off the water); a birefringent medium (the stressed plastic of the aircraft window); an analyzer (probably the second aircraft window—they are double). The colours do not appear against the clouds in her picture because the light from the clouds is not polarized.

It all goes to show that copywriters should do better research, and should bite their tongues when tempted to use the word, amazing.


Posted in commentary, weather | 5 Comments

Four birds


 Here are four (species of) of birds seen yesterday.

Most Osprey have migrated, yet this juvenile was feeding in a tree along the lakeshore.

The only striking thing about these Wild Turkeys is that while walking across a field, one chose to lift off. 

These are a few of  many Pine Siskins feeding on (birch?) catkins.

Derek Kite found this Great Horned Owl near his home.
Derek Kite’s image is used with permission.

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Fog, turkeys, hoboes


In the cool early morning, steam fog rose from a stream and drifted over the countryside.

Wild turkeys are silhouetted in the morning mist as they feed in a field.

As the fog drifts by, its droplets are intercepted by the threads of funnel webs of (what is probably) the hobo spider.

Drops on these webs are captured from the fog; they are not dewdrops.

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‘Tis the season of fall colours and my favourite is the larch, a deciduous conifer.

When this posting was made, I believed the trees shown here were alpine larches. Doug Thorburn, a man who knows his trees, assures me that, no, they are western larches. The title and text has been corrected to show this.

The colours of the western larch spill down the mountain side.

When trees are viewed across the valley, contrast and colour is muted.

The western larch is brilliant when seen close by.

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Eagle gathering


Here are a few images taken during a local congregation of eagles. They gathered with friends, to feast, vent, and dry out after a long wet night. 

To see all five eagles in a tree, move the cursor up or down over the image.



Drying out after a long wet night.


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Bighorn mating


When it comes to the mating of Bighorn Sheep, the sequence is well known.

The first step is to establish dominance over competitors. A good head butting should do this.

The second step is to pursue a fecund ewe.

The third step is to mount her…

and penetrate her. Let there be lambs.

Finally, the time has come to relax together. Life is good.

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Bighorn wooing


For most of the year, adult bighorn rams and ewes live separately. This is obviously not conducive to species propagation, so in the fall, they come together and the wooing begins.

Rams gather and jostle one another probably as a way to establish dominance.

When jostling does not settle dominance, head butting does.

Ewes show scant courtship towards rams. Their contribution seems primarily that of turning up. Here they are pouring down to the valley floor from the cliffs. Let the wooing begin.

Six rams follow one ewe.

A ram must determine the state of a ewe’s oestrus and this might involve licking her flanks and gently stroking her rump with his foreleg.

This ram obviously hopes the ewe is ready.

Five rams tagging along behind one ewe have probably smelled her pheromones.

A ram in hot pursuit has already smelled pheromones and has now opened his mouth to expose another organ which aids in determining if the ewe is in oestrus.

A young ram tries unsuccessfully to mate.   

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Bighorn portraits


There are no Bighorn Sheep on mountain slopes on the sides of Kootenay Lake. The forest is just too dense. However, there are many herds of them within a hundred kilometres of the shoreline. This is the first of what will probably be three postings about our local Bighorn Sheep. It is merely a group of portraits to set the stage for subsequent postings.

The first distinction to be made among Bighorn Sheep is between rams (males) and ewes (females). The ram with large curled horns is on the left and the ewe with shorter horns is on the right.

A profile of rams shows a horn curving strongly around the face.

While a profile of ewes shows a much shorter horn.

A group of rams holds court.

And one stares into the camera.

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Observational physics


I do little to promote my blog or website as each was created primarily for my own satisfaction. Occasionally, I mention an avian posting to a birding group, but that is about it. That others look at my material is of interest, but it is not paramount.

In the last four years, I have made 777 postings and most now receive anywhere from 50 to 150 viewings; viral is not a term that can be applied to anything I do (nor would I want it to be). So, I was curious to discover that a posting made four years ago had an ongoing and considerable viewership. What poignant combination of images and words could possibly have resulted in such continuing interest? As most of my postings are about the local natural world, might it be about a rare bird or possibly a cute bear? No. Such things pass out of viewer consciousness shortly after being posted.

Yet, the perpetually popular posting is about the natural world. Before revealing the identity of this oddity, I have to acknowledge that the ongoing favourite has not had the substantial viewer numbers as have my three hits: the desecration of a pictograph (2,920 viewings), a train wreck (2,831), and the sighting of an ogopogo (1,600). Three things characterize these postings: They are not as much about the natural world as they are about human foibles; Interest in them dies to virtually nothing within a week or so; Viewers are predominately local (western Canada).

By way of contrast, the ongoing favourite, with nearly a thousand viewings so far, has different characteristics: It is about the natural world, rather than about people; Interest has percolated along at quite a few viewers per month since the beginning; Viewers come from forty different countries and every populated continent. Links to this posting come from Wikipedia in three different languages, discussion groups, question-and-answer sites, and from searches seeking an explanation for precisely the question I attempted to address. 

It is a posting that uses physics in an attempt to explain lake-surface patterns seen during rain

Go figure.

The posting attempted to explain patterns such as seen in this picture.

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There was a lunar eclipse in the early hours of today.

When the Moon is in the Earth’s umbra (totally in shadow), sunlight cannot reach it directly. Yet it glows with two different colours: red and blue. Both are the result of light that was bent as it passed through the Earth’s atmosphere.

The red, familiar to all, is the light that passed right through the atmosphere after much of the blue had been scattered in other directions to give the blue of the daytime skies. Seen from the Moon, the Sun is blocked and the Earth’s atmosphere appears as a ring of the reddish light of many sunsets.

The blue is more subtle and, to see it, timing is important. For a short time just after entering or before leaving the Earth’s umbra, the Moon’s rim is illuminated by light that passed through the Earth’s ozone layer. Ozone absorbs reddish light but allows bluish light to pass through to give the otherwise reddish moon a soft bluish edge. 

The Moon has just entered the Earth’s umbra and appears reddish with a soft bluish edge in the northeast.

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