Blogging for Peace on Earth

Thursday, 16 April 2015

Our precious planet. Part 2: Built for Life

Photographs of the Earth from space are in themselves enough to make most people believe that our planet is unusual. But there is much more that science has revealed to show just how unusual it is, even leaving aside its placing in the galaxy and solar system (see Part 1).

So I’ve tried to list some ways in which the Earth, unlike any other planet known to date, is suitable for life.

Formation of the Earth-Moon system

While the Earth was still hot rock another planet is thought to have hit it and caused myriad fragments to fly off, eventually coalescing in orbit to form the Moon. To help in the evolution of life (see below) the Moon had to be just the right size, mass and distance, and this in turn depended on the colliding planet having the right size, mass, momentum and angle of collision.
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Temperature and Distance from Sun

The Earth’s size and mass permit it to orbit in the ‘Goldilocks zone’ where the temperature is OK for life and the tidal forces do not lock it so that one side is always dark and cold while the other bakes.

Circular orbit and tilt of axis

Unlike all the other planets in our solar system the Earth has a near circular orbit which means the temperature is stable apart from gradual seasonal variations due to the tilt of its axis.
The north-south axis, about which the Earth spins, is tilted at an angle that stops the winters getting too cold and the summers too hot. Again, this is unique to Earth. The moderate changes of spring, summer, autumn and winter in the northern and southern hemispheres are in fact conducive to the thriving of life. In fact the tilt of the axis appears to be optimal for this – not too great, not too small.

Rotational speed and stability

The laws of mechanics lead to the planet spinning on its axis once in 24 hours, a rate which keeps night and day at a fairly even temperature. (Mars has about the same length of day but its air is very thin and there is no liquid water, so that its temperature varies wildly between night and day.)

The Moon spin stabilizes the Earth’s rotation and stops the axis wobbling too much. Without this conditions would be too chaotic for life to evolve. Note that the Moon had to be the right size, mass and distance to perform this role. No other planet we know about has such a favourably placed satellite.

Tides

Tidal forces due to the Moon and Sun permit the sea to gather life-enriching minerals as it dissolves them from the land when the tide is in. Rivers also wash nutrients into the sea. The tides are likely to have played a role in the transition of life from sea to land. And certainly the lunar cycle both guides and influences many forms of life today.

Atmosphere and Ozone Layer

Today the air (nitrogen, oxygen, carbon dioxide and other gases) is right for the life of today. But when the early forms of life were evolving the composition was very different because life influences the atmosphere, adjusting its composition to suit itself. The atmosphere, in conjunction with plate tectonics, is also important in smoothing out temperature fluctuations and transporting clouds, viruses, bacteria, spores, insects, birds and dust around the globe.

There is a layer of ozone (a special form of oxygen which has 3 atoms per molecule instead of 2) which protects life from harmful ultraviolet radiation from the Sun. It was significantly damaged by CFC chemicals but is responding to restorative measures.

Water

Early forms of life are thought to have evolved and diversified in the oceans which cover three quarters of the Earth’s surface. Comets, made largely of ice, hitting the Earth in its early stages appear to be the most likely source. Alternatively the water could have come from the Earth’s interior or the cooling of the primordial atmosphere.

Minerals washed into the sea, especially salt, have maintained its salinity at an optimum level for life throughout geological time.

Water has the unique property of expanding when cooled down close to freezing point: were it not for this water would freeze from the bottom upwards and our oceans would be solid ice. we reside in the only known place in the universe where large expanses of liquid water have existed for billions of years. Finally, water is optically clearest at the same wavelength that the Sun radiates most light - had it not been then photosynthesis would have been much less pronounced and insufficient to permit anything like the varied and abundant life with which this planet is blessed.

See also The deep mystery of existence.6. Water, the elixir of life.

Asteroid bombardment

Periodic hits by large asteroids (lumps of rock up to several miles in diameter) have been at a frequency and severity small enough to allow evolution to win over mass extinctions but big enough to spur the evolutionary process. Jupiter, Saturn and other celestial objects seem to have gravitationally tuned the arrival of asteroids to match this condition. There appears to be a remarkable degree of orchestration of these events. One current theory being investigated is that dark matter on the edge of the Milky Way Galaxy played a role.

Plate tectonics

Unlike any other planet we know of the Earth’s crust comprises large plates floating on a subterranean ocean of molten rock. The heat needed for this comes from the decay of radioactive elements made in supernovas (U-235, U-236 and Th-232) billions of years ago. When the plates collide they cause earthquakes and volcanoes as well as force up parts of the crust to form land from which tides and rivers transfer life-giving nutrients to the sea. Crustal movements also bring up carbon dioxide into the atmosphere, essential for life, and, by a finely regulated process, bring ores to the surface layers where they can be mined.

Magnetic field

Because of the molten iron circulating inside the Earth we have a magnetic field protecting us from lethal solar and cosmic radiation (the Van Allen Belts). Life today could not exist without it and no other planet we know of has anything like it, as far as we can tell.

I suspect there are hidden factors which make this an even more unlikely abode for carbon-based life. Carbon is necessary for any kind of life we can conceive of because C atoms are uniquely versatile in their capacity to combine with each other and with other atoms (valency) to form the structures and systems of the living world.

Reservoir of viruses and bacteria

Right from the earliest geological epochs, i.e. over billions of years, it appears that viral and bacterial life were present. Where and how these extremely complex and sophisticated organisms originated remains a mystery. The numbers are staggering. Placed end to end they would stretch millions of light years into space and they exist at least miles down into the Earth's crust. There is a strong symbiosis between them and the rest of life. A human being has ten times as many bacteriums resident in his body as there are body cells (100 trillion vs 10 trillion, although the bacteriums are smaller). The evolution through geological time of the biosphere as a whole could well have been governed by or through them.

In Part 3 we see how the Earth is uniquely fitted to allow a high tech civilization to evolve.

Our Precious Planet. Part 1: A unique place in the cosmos

Links to all 4 parts of Our Precious Planet and related links can be found here.

John Sears

Author 2077:Knights of Peace

2077 novel: buy & preview options + reviews

AUTHOR'S FACEBOOK PAGE

cosmik.jo@gmail.com

Friday, 27 February 2015

Are some scientists from the planet Vulcan? (In honour of Leonard Nimoy)

I first published this post in 2011 but am republishing it now in honour of the passing of Leonard Nimoy who played Mr Spock in the original Star Trek series. As a keen viewer since the 1980s I have come to feel like an old friend of the missionaries on the Enterprise as they spread western ideals of love, foregiveness, justice and respect throughout the Galaxy - though never daring to mention the ultimate source of these.

Mr Spock was often teased or rebuked by his crewmates for not understanding aspects of reality that could not be deduced or induced by logic. Love and affection, for instance, are not logical and therefore should not be acted upon. Presumably, being from the planet Vulcan, Mr Spock was not familiar with Goedel’s Incompleteness Theorem, published on Earth in 1931 under the rubric Formally Undecidable Propositions of Principia Mathematica and Related Systems I.

According to the Oxford English Dictionary Goedel’s Incompleteness Theorem states that ‘in any sufficiently powerful, logically consistent formulation of logic or mathematics there must be true formulas which are neither provable or disprovable’.

Separately, the Oxford Dictionary of Philosophy entry on this theorem states the following: ‘The implied moral is that truth in some way outruns provability, at least when that is considered formally.’

This theorem is a landmark in philosophical and mathematical logic. It proves that a scientific theory of everything is inherently impossible and, by implication, we have to go to something transcendental to connect with a greater truth than that reachable by logic alone (important though logic is). What is staggering is that some cosmologists and theoretical physicists of high intelligence persist in ignoring this theorem, often, it seems in a fruitless attempt to pretend there is no creative agency behind the universe. Are they aware of the theorem or is it they don’t understand it or is it just that they don’t want to know?

Unlike scientists, mathematicians on the frontiers of computer technology are forced to adhere to it because it is a powerful tool in gauging the computability of certain mathematical functions.

For an excellent and clear account of Goedel’s world shattering theorem and its implications click here.

Finally, a disclaimer – I am not a mathematical logician or professional philosopher. I am not even intelligent by any conventional measure. However, I am interested in a lot of things and persistent and as one who believes in God I am committed to truth.

Doctrine of chance

What is truth?

Distorting reality

Doctrine of chance

Is there meaning behind random events?

The five-fold threat to science

Are some scientists from the planet vulcan?

Chimpanzees and a free lunch

John

Author,

2077 novel: buy & preview options + reviews

AUTHOR'S FACEBOOK PAGE

cosmik.jo@gmail.com

Friday, 20 February 2015

Microbiology: our changing perception of nature

Recent developments in the field of microbiology (see below), together with advances in epigenetics, horizontal gene transfer by viruses, fungal networks and quantum biology, contribute towards a perception of the biological world very different from that of a selfish-gene-driven machine. Increasingly it is seen to be an intricately interconnected ecosystem with purposeful evolution of immense complexity. The protein coding gene is only 1% of the human genome: the rest is an unfolding mystery. There is miraculous engineering, organisation, data transfer and decision taking from the macroscopic to the microscopic. Whether it is a tropical rain forest or biochemical pathways within a cell, the characteristic that stands out is one of systems cooperating to produce new systems of larger functionality.

Results of the Human Microbiome Project

A 5 year study involving 80 research institutions and funded mainly by the US government has sequenced the genes present in the bacteria, fungi and viruses, collectively known as microbes, present in and on the human body. Here are the main results as reported in Focus, August 2012, p.12 and The Economist, August 18, p.62-4.

The human digestive system alone has 100 trillion bacterial cells, which is 10x the number of body cells and weighing a total of about 1 kilogramme. NB: bacterial cells are typically only about 1/50^th the volume of a human cell, which normally has a diameter in the range 5-40 microns. In all the human microbiome contains 3 million genes compared to the 23,000 of the human genome.

There are 10,000 different species of bacteria, viruses and fungi which reside on the skin, on the palms, in the nose, intestines, throat, hair and vagina, behind the ears and in other places.

The colony present in a person is unique to that person and the variation between people is very large. Despite this variation there are a core set of functions common to all.

Disease lies dormant in almost everyone. Pathogens are present all the time and do no harm until for no apparent reason they go on the attack. E.g.: heart disease, diabetes (both 1 and 2), multiple sclerosis, eczema and asthma. Conversely, they can also protect the body from infection, as with clostridium difficile (severe diarrhoea etc.). This arises when antibiotics kill off the beneficial bacteria.

The bacteria in the gut breaks down food that cannot be broken down by the digestive enzymes produced by the body, turning it into vitamins. Surprisingly, the gut bacteria varies substantially from person to person yet the function is the same.

Expanding on this last point, complex carbohydrates are turned into formic, acetic and butyric acid. These are then passed through the walls of the gut into the bloodstream where a miraculous biochemical pathway converts them into energy or layers of fat. 10-15% of the energy used by an adult is provided in this way.

See also more recently a post dated 17 February 2015 from the Scientific American
'Microbes in our gut are essential to our well being.'

The March 2015 issue of Focus has as its cover story ‘How Bacteria change your mood.’

Antibiotic resistance

The prevailing dogma has been that bacteria mutate in response to modern antibiotics, until they become resistant. No doubt there is some truth in this, although my understanding is that the actual mutations are far from random. But a much wider picture is emerging. It now appears that bacteria present in the biosphere some 4 million years before modern antibiotics were invented were already resistant to them. In other words when ever a new antibiotic is launched on the market the chances are that somewhere on Earth there is a bacteria which can beat it. This will have big implications for drug research and evolutionary theory.

The evidence for this came to light in the discovery of bacteria present in the Lechuguilla caves in New Mexico. These had been isolated from human influences for 4-7 million years. Of those that could be grown in petri dishes over 70% were found to be resistant to antibiotics.

See

http://news.nationalgeographic.com/news/2012/04/120411-drug-resistance-bacteria-caves-diseases-human-health-science/

It may be that antibiotic resistance to any conceivable antibiotic is present in bacteria somewhere in the biosphere and it is only a matter of time before it finds its way to a patient under treatment. If so, the effort should be focused on more robust ways of treating infections.

Possibly complementing this finding there is recent evidence that resistance to penicillin, sulfonamide and tetracycline is present in soil bacteria. See

http://www.sciencedaily.com/releases/2012/08/120830141343.htm

I am sure there is much more going on in biology than I can possibly keep track of or comprehend but I hope this gives you a taste of just how much our understanding of the biosphere is evolving.