Time and time again

English: Albert Einstein Français : Portrait d...
English: Albert Einstein Français : Portrait d’Albert Einstein (Photo credit: Wikipedia)

It is often said that Einstein considered time to be an illusion, and web sites which collect notable quotes often just claim that Einstein said “Time is an illusion“. This a classic case of taking a quote and posting it out of context. What Einstein actually said was more complex and more subtle.

He actually said:

The distinction between the past, present and future is only a stubbornly persistent illusion.

He did not claim that time is an illusion, but that the moment of “now” is an illusion. In fact his equations give time the same status as space. For instance, the square of the space time interval between two events is defined by combining the square of the space interval minus the square of the time interval interval. (Provided all values are expressed in the same units.)

Time dilation spacetime diagram06
Time dilation spacetime diagram06 (Photo credit: Wikipedia)

The details don’t matter too much here. The point is that time is treated equally with the space dimensions, and no one is claiming that Einstein was arguing that space does not exist. There are many references to be found on the Internet which explain Einstein’s ideas with variable clarity and accuracy.

I said above that Einstein argued that the instance of “now” is an illusion, but I was over simplifying. What I believe that he was saying was that while we experience a “now” now, we also experienced a “now” ten seconds ago, and one second ago, and one instant ago. There is nothing special about the “now” moment and all instants of time are “now” moments.

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This isn’t that surprising really. If you consider where you are at a particular place and at a particular time, not only is there a “now” moment, there is also a “here” place. When you move to another place, you have another “now” moment, and another “here” place. To experience an event you have to have both.

If we are taking a road trip we have no difficulty with the concept that the “here” place changes continually and that a place we have passed through was a “here” place when we passed through it, and that a place further on will later be a “here” place. Where ever we are we are “here”.


You might argue that time is fundamentally different from space, in that we can see what is in front of us in space but we can’t see what is in front of us in time. This is true, but maybe we just don’t have the physical equipment to do so. We can use sight to look around as see what is not “here”, to some extent, but we don’t have complete visibility to things around us.

If we did we would not bump into things and fall off of things as much as we do. We use sight to build a picture of things around us, but we don’t have physical access to those things until we move up to them.

Human hand icon
Human hand icon (Photo credit: Wikipedia)

Since we don’t have “time vision” we have use whatever abilities we can to work out what is in the future, such as reason and intuition, both of which have limited success. We do have some ability to fairly accurately guess the future, as evidenced by our abilities to catch a ball thrown to us. If you have ever watched a top table-tennis match, you will no doubt be amazed at how accurately we can so this, as the ball whizzes from end to end of the table.

Time is measured in seconds and space is measured in metres (or hours and yards or other equivalent units). This seems to be a difference between the space dimensions and the time dimension.

Time dilation spacetime diagram05
Time dilation spacetime diagram05 (Photo credit: Wikipedia)

However it is easy to show that there is little fundamental difference. Distances are often measured in terms of time – astronomers refer to a light year, which is the distance that light travels in one year. It is not often, however, that the opposite is true. Times could be measured in terms of light metres, or the time it takes light to move a given number of metres, but this is not usual, possibly because a light metre is such a very short period of time.

Interestingly some people claim to be able to “see” the future. They are claiming that they have a sense similar to vision which they use to determine what is going to happen in the future. While it is possibly conceivable to have such a sense, there appear to be no organs in the body which could be used to “view” the future.

Panoramic view of the future Phoenix-Lake from...
Panoramic view of the future Phoenix-Lake from the observation deck of the Phoenix-Lake Infopoint (Photo credit: Wikipedia)

Such organs would have to have receptors which would have to receive information about the future just as the eyes receive information about things that are relatively distant, and that information would have to travel in time from the future to reach the receptors in the present. This appears to be counter to all known physics. Possibly “unknown physics” would allow this, but I suspect not.

In any case the human body doesn’t appear to have any receptors which could possibly serve this purpose, and although not everything is known about the human body, such organs, if such existed and could be used by some people, would be probably be apparent.

English: "Sight" - First of a series...
English: “Sight” – First of a series of 5 engravings illustrating the five senses (Photo credit: Wikipedia)

What about the brain? Could the brain perhaps receive information about future events in some way? Well, the brain is an organ for processing information, not for receiving information from the future.  There is nothing like a receptor in the brain, though it is connected via nerves to receptors which terminate those nerves and when stimulated excite the nerves which then pass the stimulation to the brain.

In my opinion, which of course could be wrong, there is no way that information from the future could be detected by the human body, and in particular by the brain acting as a receptor. That does not mean that time is in any way different from space as a dimension. What it does mean is that we are able to perceive the dimensions of space differently from the dimension of time.

Diagram of human brain
Diagram of human brain (Photo credit: Wikipedia)

That doesn’t address the question as to why the space dimensions are accessible to vision and time is not. It only addresses the question of why we can “see” the space dimension, but cannot “see” the time dimension. Something links the space dimensions into one seeming whole, while the time dimension seem singularly different.

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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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