The Search for the Fundamental

Motion of gas molecules Español: Animación mos...
Motion of gas molecules Español: Animación mostrando la agitación térmica de un gas. Cinco partículas han sido coloreadas de rojo para facilitar el seguimiento de sus movimientos. Русский: Хаотическое тепловое движение на плоскости частиц газа таких как атомы и молекулы (Photo credit: Wikipedia)

When does it stop? This screen that I am looking at, the keyboard that I am typing on, the invisible air between my eyes and the screen, even my body, all are composed of atoms, I told and believe. Apart from atoms, all there is is radiation, of various sorts.

The ancient Greek philosophers didn’t know about atoms so proposed various theories, which today seem quaint, but eventually they came around to atomism, and abandoned the other theories. In particular the theory of the four classical elements, earth, fire, water and air was dropped.

The four classical elements, after Aristotle. ...
The four classical elements, after Aristotle. Чотири стихії (за Арістотелем) (Photo credit: Wikipedia)

As I said, the theory now sounds quaint, but, given that the ancient Greek philosophers were not of an experimental frame of mind, the four classical elements could explain much of what could be observed. Everything could have been a mixture of these elements in various proportions.

After all, it appeared to work for colours – all colours that can be displayed on a computer screen can be specified in terms of the amount of the three primary colours of red, green and blue that a single pixel or dot on the screen emits. Why shouldn’t this scheme work for other things than light?

Barycentric RGB
Barycentric RGB (Photo credit: Wikipedia)

However Greek philosophers (and of course, philosophers in other cultures) noticed that, while some things could be broken down into component parts – sugar could be melted and burned, water could be driven off to leave the salts behind, and more importantly alcohol could be evaporated off and collected to make spirits, some things could not be broken down.

Gold, sulphur and phosphorus stubbornly refused to separate into earth, air, water or fire. Of course such stubbornness could be explained by the classical element theory – after all some things are easier to break down than others, but the Greeks eventually dropped the theory in favour of atomism. (This and what follows is highly simplified and condensed).

(Click here for rotating model)
(Click here for rotating model) (Photo credit: Wikipedia)

This is the belief that everything is made up of small indivisible particles which differ from element to element. The lump of gold contains billions of gold atoms, while the sulphur block contains sulphur atoms.

From about the start of the scientific revolution, people started to work out the rules of chemistry, and the ‘why’ of chemical reactions. Why did carbon in coal burn away and leave an ash? We know that the carbon in the coal burns using the oxygen in the air and creates oxides of carbon which are gasses and not easily detectable, but the experiments which led to this knowledge were preformed in the era of the scientific revolution.

So, matter is composed of atoms. That seemed to be the end of the story, as the vast majority of chemical experiments could be explained in terms of atoms, but exactly why atom A reacts in fixed proportions with atom B, but won’t have a bar of atom C. These relationships were noted but not really explained.

By the middle of the 19th century scientists began to detect problems with the “atoms as billiard balls” model. Electrons were discovered and soon related to chemistry, answering the above question. The new model, “atoms as small planetary-like systems”, had a small positively charged, and solid nucleus surrounded by a swarm of negatively charged electrons, with the electrons taking a major role in determining the chemistry of the atom.

It was discovered that many elements behaved as if each atoms of the element weighed the same, but some elements broke this rule. The gas Chlorine for example has an atomic weight of 35.45. In other words each atom weighed about 35 and half times as much as a Hydrogen atom.

It was eventually discovered that not all Chlorine atoms weighed the same. Most had an atomic weight of 35 but some (about half) had a weight of 36. To cut a long story short it was discovered that the supposedly solid nucleus was composed of a collection of other particles called protons and neutrons.

English: Liquid Chlorine in flask for analysis.
English: Liquid Chlorine in flask for analysis. (Photo credit: Wikipedia)

While the number of protons and electrons determine the chemistry of an atom almost completely, the number of neutrons contribute mass to the atom and barely affect the chemistry.

While electrons appear to be truly fundamental particles and cannot be broken down further, the protons and neutrons are composed of particles called quarks. For reasons mentioned in the Wikipedia article quarks cannot be found in isolation, but are only found in other particles.

English: The quark structure of the proton. Th...
English: The quark structure of the proton. There are two up quarks in it and one down quark. The strong force is mediated by gluons (wavey). The strong force has three types of charges, the so-called red, green and the blue. Note that the choice of green for the down quark is arbitrary; the “color charge” is thought of as circulating among the three quarks. (Photo credit: Wikipedia)

In addition to protons and neutrons, quarks make up other sub-atomic particles such as mesons. Scientists have discovered or postulated bosons which are particles that bind quarks and other fundamental particles together. From then on, things get complicated!

I haven’t mentioned the photon, which is bosonic, or the neutrino which is a fermion. All fundamental particles fit into one of these two families, and all sub-atomic interactions are the result of the rather incestuous exchange of these particles in their various groups and a strict set of rules. So far so good.

English: Enrico Fermi
English: Enrico Fermi (Photo credit: Wikipedia)

However, there are still questions to be answered. Are these particles truly fundamental or do they have components, which may or may not be particles in the classical sense? What are the sizes of these particles, if such a concept is appropriate at this level? Have we found them all? What about dark matter?

Scientists have abandoned the first question. They don’t generally refer to particles as fundamental. They have seen a long list of fundamental particles turn out to be not so fundamental after all.

Sizes of the particles may not make sense at the particle level, but the various theories may indicate sizes for some of them. There are difficulties over the size of the electron for instance. If it were a point object rather than having something that equates to size, then that causes difficulties with some theories.

As for the third and fourth questions, it appears that scientists may have found all the particles that explain ordinary matter, but naturally cautious, they don’t rule out other forms of matter such as the so called “dark matter” and “dark energy“. Dark matter and dark energy apparently interact with gravity and (from the Wikipedia article) and the Weak Nuclear Interaction.

pie chart of dark matter and normal energy rat...
pie chart of dark matter and normal energy ratio taken from en.wikipedia (Photo credit: Wikipedia)

My original question was “When does it stop?” By this I meant, which particles are truly fundamental and which have components that determine their properties? This question remains open, but if you have followed through my exposition, you will probably see that this is a question without an easy answer.

 

40 Years

Plymouth Valiant 100 of some 40 years ago seen...
Plymouth Valiant 100 of some 40 years ago seen on street in New Orleans (Photo credit: Wikipedia)

Forty years, around 14,600 days, 350,400 hours, 21,024,000 minutes, or 1,261,440,000 seconds. In other words around 1.3 gigaseconds. That’s the amount of time that I have been married to my wife, Elizabeth, known to everyone as Matty. I don’t mean to imply that it seems a long time – it doesn’t! Far from it. But it has been a long time, and I am amazed. Firstly because it has been a long time and secondly because we have stuck together for that long.

In that time the earth has travelled 37,600 million kilometres, light from earth or the sun has travelled 40 light years, or 3.8 x 10^14 kilometres. There are around 2,000 known stars within 50 light years of earth, with 133 falling among the brightest 10%, and according to my calculations around half of them are less than 40 light years away. That means that there is little chance that any LGMs will have been blinded by the flash of the photographer’s camera.

Alien2
Alien2 (Photo credit: Wikipedia)

In that time a lot has happened. We have had three children and shortly after that, moved half way around the world. The kids have grown up and we now have three grandchildren, who are also growing up fast. The youngest has been at school for a year now, and it seem only recently that her mother was just starting school herself. Thankfully the kids have not dispersed too widely and they and the grandkids will be lunching with us tomorrow to celebrate.


Embed from Getty Images

I’ve been looking at the things that have happened and changed in that 40 years. Strangely I had thought that the moon landings had not finished when we got married, but in fact there was no overlap. The last moon landing (Apollo 17) happened in 1972, before we were married. (The first landing was in 1969). Weird!

While men have not been to the moon in the last 40 years, many man-made devices have been sent to other planets and even to comets, The Hubble space telescope has sent back amazing photographs of the depths of space and other such telescopes have followed suit.

Eta Carinae captured by the Hubble Space Teles...
Eta Carinae captured by the Hubble Space Telescope. (Photo credit: Wikipedia)

One of the biggest successes in exploration of the solar system has been the Mars Rover Opportunity which has operated on the surface of Mars since 2004. It’s original planned activity period was scheduled to be 90 sols or Martian days (slightly longer than an Earth day). However Opportunity is still functioning and sending back amazing photographs much more than 10 years since it landed.

Many of Opportunity’s photographs and panoramas can be found on the NASA web site, which also contains stunning photographs, both modern and historical, of rocket and shuttle launches. It also includes astronomical photographs taken by many different telescopes and photographs taken on the moon and from orbit. I highly recommend it.

The NASA/ESA Hubble Space Telescope in space.
The NASA/ESA Hubble Space Telescope in space. (Photo credit: Wikipedia)

Of course many important happenings occurred in the last 40 years. One of the biggest was the rise of the Internet. The birth of the networks that formed the Internet happened in the 1970s, and the term “Internet” was used in a technical document in December 1974, four months before we got married!


Embed from Getty Images

Most people spend a lot of time on the Internet using a browser and viewing sites and that aspect of the Internet, originally called “the World Wide Web”, originated in CERN in the late 1980s. At some time a lot later than that I downloaded a copy of the NCSA web server and create a “Hello World” web page. I then pointed a browser at it (probably an early version of Internet Explorer) and up popped my “Hello World” page! At the time I was thrilled and delighted!

Of course not all things that have happened in the last 40 years are so great. According to the WWF the Earth has lost half its wildlife. 40 years ago global warming had not become a topic of concern, although it was first mentioned by Svante Arrhenius in 1896.

Arrhenius
Arrhenius (Photo credit: Wikipedia)

Another notable event around 1975 was the first commercial flight of Concorde in 1976. It went out of service in 2003 having failed to become a commercial success. I worked for British Aerospace at one time, though not directly on anything to do with Concorde. I also worked for British Aerospace who made the Olympus engines for the Concordes.

In 1977 the Queen celebrated her celebrated her silver jubilee, and she is still going 40 years later! I don’t remember much of the celebrations but I do remember that it was a big thing at the time!


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While searching around for links for this post I came across this useful link from the Sunday Telegraph which lists events from the last 50 years. It’s amazing how many seem to be fairly recent and at the same time a long time ago. The first case of AIDS was diagnosed in 1980, for example. The Vietnam war ended in 1975. The first test tube baby was born in 1978. Her son was conceived naturally and was born in 2006.

So much that we take for granted today was not around when we got married. No Internet as above. No cell phones. According to the Sunday Times list above, the first British mobile phone call was made by the comedian Ernie Wise to Vodafone. The first mobile phones were small bricks and had battery lives which were very short. They were also rare and expensive. Facebook, Twitter and all the other “Social Media” sites were well in the future and the multifunction devices that mobile phones have become were almost unimaginable.


Embed from Getty Images

So many things have changed that it is a wonder that anything has lasted. Our marriage has lasted, even though the concept of marriage itself has changed to include same-sex marriage, over the four decades. It seems that even same-sex marriage is becoming less popular, with couples often having children first and getting married later. That still seems odd to me, but it seems to work for many people.

We’ve made it through 40 years while all things have changed around us. I’m proud of that fact and hope that we can continue for many more. But we have a long way to go to beat my parents – they just recently celebrated 70 years of marriage.

Great Observatories' Unique Views of the Milky Way
Great Observatories’ Unique Views of the Milky Way (Photo credit: Wikipedia)