Tuesday 31 May 2011

When is proof not proof?

This is a story (with a moral) about an HQ type office, of a large corporation, in a big city. 

It had been noticed, by the staff, that one of the middle-aged male executives and a younger female supervisor, both sparkle in each other’s presence, although no obvious social contact takes place between them. 

A rumour starts.

She lives to the east and he to the west.  Sure enough, on Friday evenings, he has been seen to head east, after work. The rumour escalates. 

One of the young guns decides to follow him.  About 5 miles out of town, the exec stops to buy flowers.  The youngster drives past and ceases to follow, suspicions strengthened.  Next working day he reports back, and the rumour strengthens again. 

But no smoking gun yet.  So next Friday, the exec is followed again.  This time, the pursuit continues until, a few miles later, the exec turns into a care home car park, parks, and takes the flowers inside.  After an hour he has not emerged, so the sleuth goes home, concluding they have all been barking up the wrong tree.  And so, on Monday, he duly reports back and the rumour dies.

Meanwhile, though, after his care home visit, to his grandmother, the exec had headed off to have dinner and “afters” with the young lady supervisor.  Story to wife: “I’ll visit grandma, and, as it’ll be late, I’ll stay overnight in a hotel.”

The moral of that story is not to jump to conclusions till you have all the data. This was a favourite ruse of Agatha Christie, of course (which is why I like watching Poirot on tv).

Now try to think of as many theories, or predictions, as you can, that have been “proved correct” on the basis of a limited amount of evidence...........

Friday 13 May 2011

When is a Wave not a Particle?

I consider myself to be an open-minded sceptic, where science is concerned, as you might have gathered from my previous blog.

In physics you have to be very careful that you understand what you are working with.  Appearances can be deceptive: most people would be shocked to discover that, actually, there is no such thing as white light!  Our brains react to the different wavelengths of electromagnetic radiation (if that’s what it is!.....) by creating different colour images in our minds.  In other words, colour is a figment of our imagination!  White is what you get when the brain can’t unscramble a complex combination of wavelengths and amplitudes, and is similar in nature to discords in music/sound.  I have often wondered whether the colour images in our minds actually correspond: my green might look like your red.  We both look at something blue and agree it is blue, but our in-mind image might be different.  Deep one, that!  Perhaps, one day, when tv monitors can be wired up to show what’s in our minds, we’ll find out: one way or another.

One sometimes feels that, in physics, the left hand knows not what the right hand doeth.  Much of astronomical measurement depends on the fact that light travels in straight lines.  Telescope lenses certainly depend on it.  So, why are some people hell-bent (sorry!) on saying that light is carried by particles?  I can’t see any way that a particulate medium can carry a ray of light faultlessly in a straight line over many miles, let alone billions of miles.  Hmmm.  The debate rages on?

Look at what happens to sound.

Our auditory perception is much more detailed than our vision.  Our eardrums are sensitive to the slightest changes in waveform, so that the musically trained ear can not only tell which instrument played a particular note, but can identify the individual instruments playing in unison in an orchestral movement. 

Still, this can only happen if the musical waveforms are faithfully transmitted, from the instrument to the ear. 

Studying, on an oscillator, the intricate waveforms of a full orchestra, reveals just how complex these waveforms are, and, therefore, the exacting part that the air must play, in transmitting them.  I find it impossible to reconcile this situation with the notion that gas molecules are in a state of random excited motion.  This is sometimes explained on the basis that sound is carried by changes in pressure, so that what matters is the pressure in the intervening air.  But it seems unlikely to me that such intricate pressure variations can be faithfully transmitted, as they are, across the full length and breadth of a large auditorium, while the individual molecules are supposedly in such haphazard motion.  There ought to be significant pressure variations throughout the airspace due to this molecular agitation, which would therefore, surely, interfere with the transmission of sound.

By contrast, if you listen to music in the open air, it is subject to pronounced fade effects, depending on wind speed and direction, and convection currents.

Conclusion: something else must be maintaining the separation between molecules in a gas:  dark energy?
You read it here first!

Tuesday 10 May 2011

How Principled is Physics?

I believe that some of the established physical laws, that are normally regarded as being cast in stone, need to be subject to critical review. Exploring the farthest reaches of the universe (inwards and outwards!) is exciting, but just how much can we rely on any conclusions we make?

While early scientists, such as Boyle and Newton, were undoubtedly brilliant, and also meticulous in their work, the fact is, that they actually knew very little, compared with current knowledge.

In Boyle’s and Newton’s time, the seventeenth century, they still believed that everything was made from earth, fire, air and water.  The point being, that their imaginations, and therefore their ability to interpret scientific observations, were limited, by their relative lack of knowledge.  True, their deductions have apparently stood the test of time, but has anybody really asked the questions?

Newton’s laws of motion and gravity are regularly reaffirmed by their use in space missions, apparently, but I wonder whether the gravitation law is in fact a summary of the situation: why, for instance, do the dimensions of the force of gravity not correspond with those of the factors within the mass/distance function? (It is surely not valid to ascribe physical dimensions to a constant without identifying the underlying basis).  The gravity equation was derived from orbital data supplied by Kepler et al, not by empirical calculation from fundamental entities, and we can’t just go up to a planet and weigh it!

The laws of thermodynamics lean heavily on the original work of Boyle, Charles, Kelvin, et al.  The idea that the presence of heat excites molecules in varying degrees, to represent solid, liquid and gaseous states, was the best idea they could achieve in those times of relative ignorance, before the subatomic particles and their binding fields and forces were known.  Again, these ideas seem supported by modern practice, but are they really?  And what is the underlying basis for entropy?

Surely, the advent of particle physics and quantum theory beg the question as to whether these long-held “beliefs” are still valid.

To further underline the point: around 1850, the world’s scientists believed they knew how everything in the universe worked.  Then some silly chap called Rutherford had to spoil everything by splitting the atom, and opening up a whole new can of worms!

While the above-mentioned theories have been subject to peer review, in the past, the peers were in the same knowledge state as the theorists.

Equally importantly, how much are we still in the dark? And what future revelations might completely overturn current theories?

Will we ever be able to say, truly, that we know how everything in the universe works?

It seems to me that we need to establish a programme to routinely audit the longer-established physical laws; to make sure they are still in keeping with the latest theories.