Pebbles and People

The work of a curious fellow

This web page is on a topic that I have wondered about. I would appreciate any feedback that you might be able to provide. Especially errors in concept or calculation. Please send an email to if you would care to comment.

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The same yet somehow different...

One of my correspondents, on discovering the periodic table of elements, asked if it were true that everything on Earth was made from these elements. It does seem amazing that all objects on Earth from pebbles to people are assembled from at most, and usually much less than, 92 pieces - the number of naturally occurring elements. In fact the situation is more amazing than that.

pebbles persons

It turns out that each of the 92 naturally occurring elements are made from only three objects, protons, neutrons and electrons. As far as is known the total number of protons, neutrons and electrons has not changed significantly since they were created in the first second or so after the Big Bang. There are about 7 protons for every neutron and 1 electron for every proton. The total number of protons, neutrons and electrons in the universe is 1080 give or take a power of ten. From the existing protons, neutrons and electrons, must be made all ordinary matter contained in the universe, where ordinary means the matter we would recognize as the stuff the world is made of.

The first ordinary matter to appear after the Big Bang was hydrogen, but pebbles and people are made from many elements in addition to hydrogen. Key ingredients include carbon, calcium, oxygen, nitrogen and traces of heavier elements. These elements are only produced from the fundamental particles in the nuclear furnace at the interior of stars. Even at that it is only through the luckiest of chances that these elements are created. If not for a remarkable coincidence in the energy required to create stable carbon and the energy available in the interior of stars, nothing heavier than the element beryllium would ever have been created in significant quantities.

In spite of the heavy odds against it, we ended up, here on Earth, with the 92 elements from which everything is made. Of course pebbles and people are only temporary arrangements among these elements. The passage of a few centuries will certainly reduce a person to dust, and a few millennia will do the same for a pebble. Eventually some cosmic cataclysm might blast all this dust into deep space where gravity will go about its job of tidying up the universe and use the dust to make a new star perhaps with an Earth-like planet orbiting it. Objects come and go but the raw material from which they are made is in fact immortal.

Speaking of pebbles and people, there is clearly a profound difference between a pebble and a person, even though they are made from the same raw material. I know that a person can appreciate a pebble, its smoothness, pleasing colors and so on. As far as I know it is not possible for a pebble to appreciate a person, her beauty, her cheery personality and the like. Exactly what accounts for this difference is a question that has not been satisfactorily answered by scientific investigation yet.

The distinction might be expressed as the difference between a passive and active participant in history. The pebble is limited to following Newton's laws, only changing its velocity when pushed by some external force. The healthy person can make a decision to move and carry it out, without benefit of external actors. Furthermore the person can select among a huge number of possible movements, the one most likely to alter the future state of the universe to one the person thinks is desirable - possibly picking up a pebble to admire it more closely.

Human beings, of all Nature's animals, seem to have an extraordinary ability to predict and to some degree control the future states of the universe... well most human beings that is. I have known four-year-olds with an amazing degree of that skill, and forty-year-olds with a seriously diminished capacity to either predict or control the future. Sadly many of the latter end up in the custody of the criminal justice system, possibly because of nothing but a failure of imagination.

In the following pages I will try to provide some of the thinking behind my assertions about the differences between people and pebbles, beginning with some thoughts on the behavior of pebbles, then moving on to the more complicated issue of the behavior of people including how they alter the future of the universe.

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