Tuesday, April 24, 2012

Dark Matter

Supposed distribution of dark matter in the galactic halo

Our series about ill-guided science would not be complete without discussing a very "dark" chapter of modern science - the topic of so called "Dark Matter".
After scientists found out that the measured density of matter in the universe could not explain its flatness and that there needed to be about ten times more matter than could actually be observed; that the observable matter could not explain intergalactic super-structures; and that galaxies rotated with such a high velocity that its matter would not be able to hold them together; it was obvious that there was something wrong with the existing models of the universe. But everybody had become so accustomed to the well-known models of gravity, the Big Bang and black holes, that nobody was willing to throw them over board so easily. Something needed to be done to save these beloved theories and reality could not be allowed to get into the way of such nice models.

So scientist introduced some mysterious variable into the equations. The "dark matter" was born. They could also have resorted to some supernatural power like a god who would keep things together and do what the missing matter in the universe was not able to do, but the term "dark matter" simply sounds more "scientific". People had already become used to things like "black holes", so "dark matter" fitted quite well into the faith of theoretical physics.
In fact "dark matter" has a lot of things in common with a god: First of all it is invisible. This is an important advantage, because it makes it difficult to disprove it. Second, since it is undetectable, you can give it any attribute you need to support your model of the world. So theoretical physicists were exactly able to calculate the amount of dark matter as 83% of the total matter in the universe, which was the amount they needed to save the existing models. Since there was no way to detect dark matter, there was also no need to measure this number, which is always quite convenient. Since nobody could see or understand this mysterious dark matter, the priesthood of theoretical physics had the sole authority to interpret and describe this esoteric substance.

Unfortunately some heretical astrophysicists have recently spoiled the fun for the theoretical physicists (http://arxiv.org/abs/1204.3924). They measured the dynamical surface mass density in the galactic neighborhood of the sun and found no indication for the presence of dark matter as common theories would suggest. This will probably not be the final death blow of "dark matter" and theoretical physicists will most likely come up with some adjustments to their theory, but it shows that a lot of those models of theoretical physics are just invented out of thin air and always circumvent any experimental proof.

If a measurement deviates a whole magnitude from the predictions of a theory, like the measured density of matter does, the normal reaction should be discarding the theory as useless. Why are theoretical physicists not reacting this way? If the observable matter in the universe is not able to explain the observable effect of gravity, then probably our theory of gravity is wrong. The scientifically correct attitude would have been to declare Newton's law of universal gravitation as wrong. 

F = G \frac{m_1 m_2}{r^2}\
Possibly wrong.
May be it is only an approximation for planetary distances but incorrect for interstellar or intergalactic scales.
We have no explanation for the surprising discovery that the universe expands at an accelerating rate, although gravity is supposed to slow it down. Perhaps gravity has a reversed effect over intergalactic distances. But this cannot explain, how galaxies are held together by such little matter. It seems that the effect of gravitation is higher than it actually should on a galactic scale. There are so many unanswered questions regarding gravity, that we should simply admit that we don't have a working model of gravity at the moment. 
Instead we invent theories of speculative objects like black holes and other singularities with arbitrarily extrapolated values of our flawed law of universal gravitation. May be there is an upper limit for the density of matter, perhaps in the magnitude of atomic nuclei, which is by coincidence also the density of a neutron star, an astronomic object that can actually be observed, different from black holes, which are just based on speculations. We even have theories about so called "Hawking radiation" that causes black holes to slowly evaporate and other descriptions of odd phenomena of singularities like wormholes, white holes etc. We have faster than light inflation of the universe in order to save the otherwise failed theory of a Big Bang, we have a string theory with up to 26 dimensions, of which only four are apparently observable.

When is it finally enough with such weird speculations? What does this have to do with science, which should primarily be occupied with explaining actual observations?
This has nothing to do with what science is supposed to be. This is at best some philosophical exercise. We need to bring back rationalism into scientific research. And we need to limit science to what we can actually observe. We should get our feet back on the ground, think about what we really know and only make research about subjects where we have an actual chance to find answers instead of inventing more or less unfalsifiable speculations.
Let's be honest. We have no idea how the laws of physics work outside our solar system. We have no idea about the origin or the future of the universe. We cannot jump to conclusions based on theories. We have to observe the world and then come up with possible models of our observations. As long as we haven't seen a black hole or some dark matter, we don't even need to ask a question about it.

Wednesday, April 18, 2012

Global Warming

The issue of global warming has passed from being a question of scientific interest to being a religious topic. It provokes strong emotions among believers and disbelievers and you better think twice before offending the religious feelings of one of the followers of this religion, since they can be very zealous defending their object of worship. The clerics of this new religion, the so called "climatologists" don't research to make new discoveries about this topic but to prove their opinion that they already had.
The opinion about Global Warming doesn't depend much on the information that people have acquired about it, but rather on their overall political stance. As a democrat they will most likely believe that it exists and is man-made, as a Republican they will probably reject one of these two claims.
The scientists that work on this topic are furthermore only interested in possible economic and political impacts of the phenomenon and not that much of its biological relevancy. Global Warming is depicted as a disaster scenario for the global ecosystem in order to exaggerate its importance. But nothing could be farther from the truth. Some basic facts of ecology are simply ignored. The question if Global Warming may be positive or negative for the ecosystem is not even asked. It is taken for given that it is something negative emphasizing the rather exotic examples of some individual arctic species or micro-ecosystems.

But when judging the impact of Global Warming on the sustainability of life on earth, we have to look at the big picture and recall some basic principles of biology that are actually well-known but totally overlooked.

The Temperature Problem

The temperature range in which organic life can exist on a planet is basically defined by the temperature in which water can exist in a liquid state. Under the pressure of earth's sea level the lower limit is 0° C and the upper limit is 100° C.
This can vary insignificantly depending on solvents in the water (Salt water freezes at lower temperatures.) but not by a large margin.
It was formerly thought that the upper limit was determined by the temperature above which proteins would be unable to maintain their folding structure, which was assumed to be around 60° C, but this was disproved by the discovery of thermophilic bacteria that can survive over 100° C. So the theoretical limits for the sustainability of life seem to be determined only by the freezing and boiling point of water.
Now earth"s average surface temperature is estimated to be about 15° C, which is apparently much closer to the lower limit than to the uper one. There is no place on earth were the upper temperature limit is reached, but the polar regions are far below the lower limit and can't sustain organic life. There are still some carnivores living in those regions but their food source is produced in warmer climates. Plants cannot maintain a higher body temperature than their environment and they are at the base of the food chain.
This means the temparature of earth is not optimal for organic life. Earth is on the lower limit with large areas being below it. Further cooling would be a serious threat for life on earth, warming can only improve the situation, because it would make new areas habitable, which currently aren't. But there is no place on earth where a temperature increase of 20° or even 30° would bring it over the upper limit for sustainability of life, not even on the equator.
If polar and sub-polar regions become warmer, life forms from moderate regions would simply migrate there. The vegetation zones of earth would shift, but life forms adapted to colder environment would not just die off and leave a deserted wasteland. The opposite is true. The bio-mass of earth would actually increase.
So there is no temperature problem.

The CO2 Problem

Rising CO2 concentrations are described as a problem. However for many plants on earth CO2 is actually the limiting factor of growth. For this reasons many greenhouses artificially supply CO2 to increase the growth of their plants. While the normal CO2 concentration in the environment is 392 ppm, increasing the CO2 concentration up to 1,000 ppm results in photosynthesis rates, which are 50% higher. This is a well-known practice in commercial greenhouses to increase the production of crops. 
The CO2 concentration also was far higher in earth's geological past than today. During the Jurassic period  the CO2 concentration was about 2,000 ppm, 5 times higher than today. During the Cambrian period it even reached 7,000 ppm (almost 20 times higher than today) Whatever fossil fuel we might burn today, it once was already in the atmosphere, because this is how coal, oil and natural gas formed in the first place. They are fossilized bio-mass made from carbon in earth's atmosphere. Man has no means to produce carbon artifically and introduce it into the natural cycle of the ecosphere. Man can only use carbon that has already been either in the atmosphere or in the oceans at some time in the past. A man-made catastrophic accummulation of CO2 in earth's atmosphere is therefore technically impossible. We can only restore the COconcentration to a level that it once was. And an increase of CO2 would even be beneficial for earth's vegetation, since all carbon that is currently stored in fossil fuels had been taken out of earth's carbon cycle. By burning fossil fuels we only put the carbon back where it belongs.
The other question is to which extent COis the cause or the effect of Global Warming. We know that most of earth's COis in the ocean and that any warming causes water to release some of the COit contains. You can see it by comparing the CO2 released by a warm and by a cold bottle of Coca Cola. So the question is, whether an incrase of COin the atmosphere is the result of industrial emissions or the result of the warming of the oceans rather than its cause. 
Either way COis no problem to worry about.

Rising Sea Levels

Global Warming will indeed cause sea levels to rise, which is particular problematic because of the population density along the coast lines. But there is a simple solution to it, which is migrating further inland into less densly populated areas. It will of course reduce the available land surface of earth and aggravate the problem of overpopulation, but the problem of overpopulation is first of all due to high birth rates and a low mortality. So a loss of land surface would only contribute insignificantly to this problem. If we seriously want to deal with the problem of overpopulation, we would have a far stronger effect decreasing the natality and increasing the mortality than preventing an insignificant loss of learth's and surface. 
There are however economic and political difficulties involved, since several countries are at risk of disappearing completely like the Fiji islands or Bangladesh. But this is not a scientific issues. Nevertheless it is one of the reasons why politics and money get ivolved in the issue of Global Warming. It would require a new distribution of available land resources among the existing nations. And another reason is that COemissions are closely related to the issue of energy resources. This makes it highly relevant for politics and economy.
For the global ecosystem itself it is irrelevant, if the ratio between water and land surface shifts a few percent, especially when at the same time vast land surfaces in formerly too cold latitudes get suddenly inhabitable.
For the global ecosystem rising sea levels are therefore no problem, but for the human economy and political entities they are.

As we can see, Global Warming is not so much a biological problem but a political and economic one. And these are the factors that provide the funding of scientific research. And at the same time these same powers have a vital interest in a particular result of this research. So every scientist working in this area will always be biased depending on those who sponsor his work.
It is also closely related to the general political stance of these sponsors as well as the scientists. Global Warming has become part of one's ideology. As such it must not be questioned and defended against all critics and doubts. The question of Global Warming is no scientific question anymore, it touches all you believe in. It is a question of faith.

Therefore we don't need to expect any useful data about this topic to be published. Just as religious writings don't contribute anything useful to questions about the nature and origin of the world, papers about Global Warming won't contribute anything useful to the question how the global climate will develop in the future.
But it is comforting to know that this question is no threat to the ecosystem anyway. It can only be beneficial.