The Fly, Eye and Tax

I started today with flies on the brain.

I’ll start you with a whimsy to get you in the mood. That old saw, time flies like an arrow, fruit flies like a banana.

Seismographs

‘My idea is simply this. Let’s try to invent a seismograph using a vacuum tube to detect the earth vibrations so that it will be sensitive enough to register the vibrations made by simply dropping a heavy chunk of lead on the ground.’

‘To give you an idea how sensitive they are, imagine a bar of steel one-half inch in diameter and a foot long clamped in a vice. Imagine a fly lighting on the end of it. Vacuum tubes are sensitive enough to measure the deflection of the bar of steel due to the weight of the fly!’

So wrote Scott Petty to his brother Dabney on April Fools Day, 1925. What they wondered was whether the portable seismograph invented by the Dr Mintropp in WW1 could be improved. German physicist Mintropp had started out started by trying to detect and triangulate enemy guns from their vibrations. His refraction techniques created a new tool that created a global business in the search for energy resources below ground. Dabney wanted his brother Scott to engineer their way into a share of the ‘landslide business’ the German company Seismos was doing. Seismos was being particularly successful in the US hunting for shallow salt domes that trapped vast reserves of hydrocarbons.

Some fifty years later, my first job as a geophysicist was with the Petty Company. By then they had become Petty-Ray and then Geosource and later HGS, a typical series of consolidations that happen in evolving technology businesses. The Petty brother’s prototype reflection amplifier was stolen in 1927 but their second version was vastly improved and formed the foundation of the Petty Company business. A key to their success would be well understood by today’s computer engineers. Scott Petty shortened all of the wires in the core oscilloscope to eliminate vibration noise created by wind. I came to know how this equipment worked and looked because I used to show the 1920’s technology to visiting clients in the 1980’s. This was easily done because the Petty Museum surrounded the reception area of the global HQ located in Sharpstown in SW Houston.

Eyes

You may not agree that Drosophila, the common fruit fly, has beautiful, compound eyes. One day, about a decade ago, some scientists were looking deep into those eyes and observed something quite unexpected. Cambridge neuroscience researchers Franze and Hardie found that fruit flies have mechanical eyes. Their sensory perception isn’t purely biochemical. Their rods contract when photons hit them. This is oversimplified yet you might wonder if their other senses also have a mechanical element to them. I don’t know much about proteins called transient receptor potential (TRP) ion but we humans have 28 different types of TRP involved in to taste, pain, and blood pressure regulation, for example. And in fruit flies, it’s their TRP that activates the contraction of the rods in the their eyes.

The housefly also has compound eyes, like visors studded with many hundreds of small lenses. The lenses create many hundreds of images. Fly vision is not high resolution but the resolving power is sufficient to enable the determination of scale, vectors and velocity of movements by basic trigonometry. You probably realise from futile attempts at fly swatting that the biological machine that is the fly operates at ten times the speed of us humans.

What you may not have thought about is how you couldn’t see the flicker in the old fluorescent light bulbs. In these parts, the 220 volt electric current is delivered at 50 hertz. You will recall how this electric energy drove the fluorescent tubes that were once so common, powering 50 cycles of illumination every second, effectively continuous for us humans since we can’t detect anything faster than 20 cycles per second. You’d know this limit if you think about the frame rate as the old celluloid strips passed across the projecting light to create the illusion of the movie. But for the fly, in the fluorescent light of an office or its movie-going mate, both metabolising at ten times our speed, there’s a lot of dark and boredom between the flickers and the frames.

Time

As a photographer, speed matters to me. I regularly open the shutter for four milliseconds to gather enough light to render an image worth sharing. And now that my cameras have ‘electronic’ shutters, the light gathering can be reduced to mere fractions of milliseconds.

Two milliseconds was the most common time sampling period when I was a geophysicist. Listening for energy reflected back to the surface might last as little as two or as much as ten seconds before we realised we could listen 24/7. But the digitisation of the energy was typically done every two milliseconds. From these time samples, detailed pictures of the subsurface could be imaged and interpreted in the hunt for occluded hydrocarbon reservoirs. This is analogous to your CT or MRI scans used for medical investigations but far more complicated and challenging. Sometimes the velocity of sound in rock is such that four milliseconds is too long to resolve the layer that might hold hydrocarbons.

As a lapsed geologist, I’m comfortable thinking about tens of millions of years as being short periods of time. As a geophysicist and a photographer, I often think that two milliseconds is a long time. The earth itself, some four billion years of age is young relative to the origin of this fourteen billion year old universe.

Numbers

Since I’ve digressed to numbers, 100 billion is a large number. That’s how many messages are sent on WhatsApp every day. If I was an alien who had designs on inhabiting our planet after removing us, I wonder what I’d do to incapacitate the humans? Viruses are much in the news at the moment. Water is vital to all life. Electricity is vital to everything. Can you imagine how much electricity it takes to send a WhatsApp message. Of course that calculation has been done many times already. Tim Berners-Lee, the guy credited as the internet inventor, had a go in his 2010 book How Bad Are Bananas? He calculated 4 g of CO₂ are needed for an email. Since this is about emissions, he estimated that a text message emits 0.014 g. Hard to know how to portion out a WhatsApp message but make it the same as a text message, definitely less than an email, and you’d be emitting about 1400 metric tonnes of CO₂ every day that you publish 100 billion items.

Do you know much about carbon taxes paid by the search and social media companies?

References:
Seismic Reflections, O Scott Petty (1976)
How Bad Are Bananas?, Tim Berners-Lee (2010)