Clas Blomberg - Physics of life-Elsevier Science (2007)

406 Part IX. Going further
of all matter into radiation, proposed, but not verified by some basic physics theories, or
there can be compressions into black holes which are suggested to represent high entropy.
There are several proposals of a universal heat death. There are also many ideas about how
future humans can develop various possibilities to survive at situations far in the future. These
have also considered situations of strong cooling, down towards the absolute zero during a
continued expansion period (Tipler, 2005).
Are we now satisfied with this scenario, with this description of the beginning of a thermodynamic
time and possibility of entropy increase? When we accept the natural laws as we
know them and the densities of energy and matter, this is an appropriate scenario that keeps
together and gives proper answers.
But physicists are eager to take further steps and ask further questions. What about the
natural laws and what about the densities? When we take such steps, there are new questions
and one gets to very bewildering questions that even if all that is far beyond a simple
physics of life, they put very intriguing aspects on one of our main questions: what are the
prerequisites of life? And then we get to the puzzling aspects of what is called “antropic
principle” of the next chapter.
§ 38 WE LIVE IN THE BEST OF WORLDS:THE ANTHROPIC PRINCIPLE
This has been claimed by many philosophers and may in the western tradition go back to
Plato who claimed that the creator, the demiurge, had made our world as good as possible.
Sometimes, when one sees the struggles amongst humans, one may doubt. But when one
looks at some detailed physics, the point is clearer. We live in the best of worlds. At least
for the development of life.
The earth is a perfect place for life—filled with water where life probably originated and
developed, a lot of minerals that are important for many chemical reactions, and also full
of easily accessible carbon compounds, oxygen and nitrogen, which are important for the
basic compounds of the living cells. When one looks at the abundance of elements in the
solar system, one finds that they vary naturally, the lightest one, hydrogen, is the most common.
More than 90% of common matter in the universe is hydrogen. Helium, the next
lightest element, is second in abundance, but that is not relevant for us as it does not form
chemical compounds and does not contribute to the processes of life. (As we shall see
shortly, it plays an important role of building up the relevant elements). Then, the next common
elements are in the order: oxygen, carbon and nitrogen, the most relevant elements for
forming the basic biochemical substances.
The most important elements for forming substances of biological relevance are the
commonest elements in the universe and in the solar system. The prerequisites for developing
life is the best possible. This also concerns the temperature on earth, allowing liquid
water but is also low enough that important chemical compounds can remain in the atmosphere
or solved in water, they do not in any large extent react spontaneously. On the other
hand, the temperature is large enough to allow fluctuations that can drive may processes
and which are crucial for the living processes.