Nebulosity

English: Cumulus cloud above Lechtaler Alps, A...
English: Cumulus cloud above Lechtaler Alps, Austria. Español: Nube cumulus sobre los Alpes austriacos. Deutsch: Cumuluswolke über Lechtaler Alpen, Österreich. (Photo credit: Wikipedia)

Clouds are collections of water droplets suspended in the air. A cloud is formed as the water vapour in the air condenses onto particles of dust or other water droplets. The water in a cloud weighs tonnes! It’s a good job that the droplets don’t have time to coalesce into great balls of water before they reach the ground, but I suppose that to insects a droplet is a huge ball of water, and able to cause havoc.

As anyone who has flown in an aircraft is likely to know, clouds are not well defined, and in fact they could be described as nebulous or hazy. From a mathematical point of view they are fractal and the fractal dimension (a measure of their fuzziness) varies depending on the cloud.

Fractal plant curve, made using an L-system
Fractal plant curve, made using an L-system (Photo credit: Wikipedia)

A common pastime on a summer’s day is to imagine shapes in the clouds. That one may look vaguely like a car, that one like a dog, and so on. But really, the only shape that clouds have is “cloud-like“.

There are many types of cloud shape, depending on the conditions and the altitude where the cloud is forming, but the usual depiction of a cloud generally looks like a cumulus type. This type forms the usual shape like piles of cotton wool in the sky, with mountain, canyons, and even castles.


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There is always water vapour in the air, even if it doesn’t form clouds, although we cannot see it. As I said above, clouds are formed when this water vapour condenses on small particles in the air (and other conditions are right). Sometimes there are attempts to make rain by “seeding” a cloud with small particles to increase the rate of condensation and thus increasing the size of the water droplets.

At a certain  size the droplets become to big to be buoyed up by the air and start to fall, picking up more moisture as they do. As I understand it, this cloud seeding process is limited in its success, but I may be wrong.

Cessna 210 (OE DSD), rebuilt for cloud seeding...
Cessna 210 (OE DSD), rebuilt for cloud seeding, with 2 silver iodide generators (Photo credit: Wikipedia)

Clouds sometimes form at ground level, if the conditions are right, and then we call them fogs or mists. This often happens when light rain is falling and there is a lot of moisture in the air, but it can happen simply because the conditions are right.

Living where I do, I occasionally have reason to visit the local airport in Wellington. The airport is situation on a section of land that was brought up by a an earthquake, so that it is on a narrow stretch of land between two sets of hills. Over the hills to the East of the airport is the entrance to the Wellington Harbour.

English: Aerial view of the Miramar Peninsula,...
English: Aerial view of the Miramar Peninsula, Wellington, New Zealand. Wellington International Airport is visible and the beach just above the left-hand end of the runway is Lyall Bay. Downtown Wellington city, the harbour and port can be seen in the distance. (Photo credit: Wikipedia)

On several occasions I have seen sea mist roll in from Cooks Strait to the South and extends tongues of thick mist over the airport and the Harbour entrance. This causes the airport to shut down until the conditions have cleared, spoiling the travel plans of hundreds of people.

Other clouds which are familiar to many are the stratus clouds. These clouds are layers which cover all or most of the sky under some conditions. They often presage rain or other forms of precipitation. Stratus clouds range from light to dark and in many cases might cause a drop in one’s spirits.

English: Stratus undulatus clouds. I took this...
English: Stratus undulatus clouds. I took this picture out the car window on the way to Vancouver. (Photo credit: Wikipedia)

Certainly the dark stratus has that effect on me, and there is little that is more spectacular than breaking through a layer of cloud in a plane. The tops of the clouds will be brightly lit by the sun, and sometimes whorls or rivers of cloud can be seen from above.

The tops of the clouds can be quite lumpy and cumulus-like, and descending into the clouds is like descending into mountains and canyons and the lumps and bumps of the cloud can whizz past like scenery on a train, until the plane finally breaks through the greyer, darker ceiling of the cloud layer.

English: "The two main cloud types are St...
English: “The two main cloud types are Stratocumulus mixing with Cumulus in the foreground with Cumulus beyond” ~ Identified by http://www.cloudappreciationsociety.org/ (Photo credit: Wikipedia)

However, broken stratus clouds are the clouds which produce amazing sunsets as the sun drops through the layers and gaps in the clouds. Very often a beam of sun breaks through a stratus layer and lights up the water droplets or dust producing what looks like a column of light. These rays are known as crepuscular rays.

Add to that the amazing colours that result from the breakthrough sun beams and the dust and water droplets and sunsets can be very beautiful, even if the sun light is in fact refracting or reflecting from pollution in the air.

Crepuscular Rays and over
Crepuscular Rays and over (Photo credit: Wikipedia)

When the sun has gone below the horizon, it can still illuminate clouds above the horizon causing them to glow with an orange light, as the blue light is absorbed by the thick layer of atmosphere these rays which are almost tangential to the earth’s surface have to pass through.

Cumulus clouds are often sought out by glider pilots, since they are often formed by an up welling of air over a particularly warm piece of land. The up welling of air provides the glider pilot with extra lift, which allows them to travel vast distances, but a downside is that some clouds can be chaotic and turbulent. Birds will often guide a pilot to the up draughts there is no cloud.


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Another totally different sort of cloud has appeared over recent years, and that is the Internet cloud. The Internet cloud is also somewhat nebulous, and allows us to take a photograph on one device (computer phone or tablet) and view it almost immediately on another device.

The cloud (often the Cloud) also allows for automatic backups for devices – if your device implodes or is lost or stolen, your data is safe. Mostly. For if you sync (synchronise) your device with the Cloud, and then delete a photograph, it will shortly be removed from the Cloud and lost.


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To prevent data loss, you can backup to somewhere else on the cloud, so there are two (or more) cloud copies, or you can backup to a local computer or local storage, so that if you delete something by mistake you can always get it back. As anyone in the computer business will tell you, one backup is never enough!


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How do I get from A to B?

Ngaio Tree; Português: Mulateira. Portimão, Po...
Ngaio Tree; Português: Mulateira. Portimão, Portugal. (Photo credit: Wikipedia)

We had reason to visit another suburb today. It wasn’t until I was sitting waiting for some traffic lights to change that I thought about how I was navigating from home to destination.

We just got into the car and drove there. I didn’t consider the route in advance, and it seemed that I just pointed the car and we got there. Obviously I knew the way, as we had been there or through there a number of times in the past. But I didn’t have the destination in mind from start to finish, at least not consciously. I’m not sure that I had it in the forefront of my mind at all.

English: Driving Route 40 to El Chalten was pu...
English: Driving Route 40 to El Chalten was pure driving pleasure. (Photo credit: Wikipedia)

I knew that it was in that direction though, and that did not leave a lot of route options. I did have a general feeling that I should go south, in this instance and that really only leaves two options, the back road, or the motorway. The back road is a lot prettier!

I made the choice to take the back road but it was not, as I said, at the forefront of my mind, as I was doing other things at the time, like finding my keys, my phone, my wallet and these things occupied the forefront, while the decision about which route to take was more background.

English: Mind the dip Looking down the road is...
English: Mind the dip Looking down the road is a hidden dip. The farmers are busy with the harvest while the weather stays dry. (Photo credit: Wikipedia)

So the route was chosen more of less in the background, but not subconsciously. Much the same process happened on the way there, and at each junction or turning point, I didn’t have to consider at the front of my mind which direction I should drive. I just did it. Some part of my mind knew that to get to our destination I had to turn right, or go straight on or whatever.

This is good because the front of my mind was doing the driving, keeping the car on line, signalling, accelerating or braking, keeping us safe on the road. Except that it wasn’t right at the front mind, since I was also talking to my wife about various things. Christmas things from memory.

English: Two motorcycle trailing off the brake...
English: Two motorcycle trailing off the brakes through Tooele Turn at Miller Motorsports Park. Rider on the white bike is Warren Rose, Rider of the green bike is Dave Palazzolo (Photo credit: Wikipedia)

I’ve been driving for many years and I’m confident that if needed the driving part of my mind can instantly oust the things currently in my mind should the unexpected happen. Many year ago, when I used to smoke, I was driving with a friend and an emergency happened. When it was over I realised that I was no longer holding my cigarette. Meantime my friend was scrabbling between his legs where my cigarette had ended up when the driving part of my mind grabbed precedence and the cigarette holding part was temporarily ousted.

The route planning part of my mind would not suddenly get control like that, fortunately. That would be highly dangerous. I could if I had wanted have brought the route planning part of my mind to the front, but it wouldn’t say much except “turn left at the next junction”.

Turn Left, Turn Right
Turn Left, Turn Right (Photo credit: Wikipedia)

I have on occasion made a navigating mistake. I’m going to A and the route to B is the same in part. Suddenly I realise that I have missed a junction and will have to backtrack. It seems that the route finding part of my mind spends much of the time dozing and checks in only infrequently, sometimes missing the turning point or ritually following a more usual route.

It also seems that the information it keeps is like an instruction to take an action at each decision point rather than the whole route from home to destination as well as a general direction, less well specified. GPS guidance systems seem to work this way too in that they instruct you to take an action at each junction without setting out the whole route each time.


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The model of the mind that I’ve used above, of various parts of the mind at various levels of “forefrontness” or consciousness is nothing new. The need to make a part of the mind the one at the top of the conscious levels, suddenly as a result of a danger, or selectively by choice, as in route following reminds me of the way that computer programs

Computers have several methods for navigating through programs and reacting to things that happen when they are running. One big part is called “handling errors”. Dividing by zero is an error and if the computer reaches a point where it has to divide by zero something needs to be done. The program can report the error and gracefully stop, or it can take some action to fix the error and then carry on.

English: A Texas Instruments TI-86 graphing ca...
English: A Texas Instruments TI-86 graphing calculator displaying an error message, indicating that the user or a running program has attempted to divide by zero. (Photo credit: Wikipedia)

Computers handle error by means of “interrupts”. Whether the errors is software (eg divide by zero) or caused by hardware connected to it (eg input/output errors) the computer stops what it is doing and runs a bit of program that handle the errors by sending a message or fixing things up. The bits of program that were running are suspended and after the error is handled the bits that were running may be given back control.

The mind seems to work in a similar way. When an emergency arises the current part of the mind that is at the forefront gets suspended and the emergency is handled by another part of the mind. A pedestrian steps into the road and you react by standing on the brakes “before you know it” as the saying goes. As soon as the emergency is over, the conscious mind takes over again.

a short .gif of the Taiwanese animated pedestr...
a short .gif of the Taiwanese animated pedestrian road crossing sign (Photo credit: Wikipedia)

You do indeed react “before you know it”, one might say instinctively. But humans have not been driving cars for much more than one hundred years, so it appears that the reaction is not instinctive in itself, but is an instinctive reaction to a danger that has been learned. We seem to have this fast reaction to events which is instinctively based but can be applied to learned situations, which is much more flexible than hard-wired instincts would be.

So, pondering on how I get from A to B has led me to conjecture that there are parts of the mind which are forefront in our minds and other parts which are not directly in the forefront but which can be brought to the forefront in an instant, when an event happens. It is evident that these parts are only partially backgrounded as the mind as a whole has some aware of the location at the time, but they do act semi-autonomously, that is until the pedestrian steps out onto the roadway.


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Evidently there are parts of the mind that are less foregrounded and more backgrounded. When the part of the mind that is concerned with driving wants to signal or change gear, another part of the mind which controls the arms and legs wakes up and make the limbs move as needed.

I’ve spoken above as if all these different levels are discrete states, but I think it more likely that is a continuum from the foreground of the mind to the background or a least the series of levels of consciousness are close enough togerther to appear so.  The mind is a complex and wonderful thing.


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[Comment: After finishing this post I went looking for other discussions of the same topic. I first found this Wikipedia article which has the issues mentioned in the article’s header. Interestingly the implication in the article is that there is a single level of consciousness at any one time. This I do not agree with. Another article I found was a little better, I feel, but only because it acknowledges that several levels may be active at the same time, but divides them into three levels with well defined scopes. I feel that it is a lot more complex than that, with all sorts of sections of the mind at all sorts of levels being active at the same time. Neither article deals with the issue of one section of the mind apparently seizing the highest level when an external event triggers it.]