10:00 am

Yesterday I read chapter 3 & 4 of "The Canon". This book is growing on me. Now for a few notes.

Chapter 3 Calibration

• "Throughout our history, people have wildly misjudged distances, proportions, comparisons ..." [p. 72]
  
  
• "By all appearances, we have evolved to view life on a human scale, to concern ourselves almost exclusively with the rhythms of hours, days, seasons, years, and with objects that we can readily see, touch, and count on, because those are what we have to work with, those are the ambient utensils with which we must build our lives." [p. 72]
  
  
• Factoid: "The earth's dancing has been gradually slowing down, largely as a result of the tidal tugging of our tagalong moon. Early on, the earth completed a twirl in only ten hours, and even as recently as 620 million years ago a day was done in 21.9 hours." [p. 73]
  
  
• "What little visceral sense we have of history tends to be based on the average human life span ... Any interval greater than a century in either direction blurs our mental calendar ..." [p. 74]
  
  
• "The scientists I interviewed were unanimous in their conviction that people would benefit enormously from a better grasp of nature's true dimensions: the length and breadth and tenure of the visible universe, the timeline of life on earth, the sublime spaciousness that persists even down to the imperceptible atom." [p. 75]
  
  
• "Our perception of time is very unusual and hard to find in other systems of physics. It's easy to find extremely short time scales, like those that apply to many subatomic particles, and it's easy to find extremely long time scales, like those that pertain to the universe and to very stable particles, but it's very unusual to find scales like hours, days and years." [p. 76]
  
  
• One approach is to rescale a metric into one that is more familiar. Imagine the earth as a human being with a seventy-five year life span. When one does this one finds out that homo sapiens arrived only during the last day! [p. 80]
  
  
• The same idea can be used with distances. Imagine the sun as the size of an orange, then the earth would be a grain of sand about 20 feet away, and Jupiter would be a pebble about 84 feet away. ... Our galaxy would be about 24 million miles across. [p. 81]
  
  
• "Just as ... the interior of an atom is composed almost entirely of empty space, so, too, is the kingdom of the heavens. Nature, it seems, adores a vacuum." [p. 82]

• Consider small distances such as the size of an atom. If the nucleus of an atom was the size of a basketball at the center of the earth, then the electrons would be found at the outer layer of the earth's atmosphere. [p. 86]

Chapter 4 Physics

• "... many scientists have been campaigning for a flip in the educational sequence, teaching physics first, the life sciences last. ... argue that physics is the foundation on which chemistry and biology are built." [p. 88]
• "Everything, every single thing deserving of the designation 'thing', is made of atoms." [p. 89]
• "If we could blow up an atom to something the size of a paperweight, 'what would we see'? ... It depends on your definition of see. ... When we talk about seeing things in the everyday world, we're talking about ... photons of light. ... But when you get down to the scale of the atom, those photons change the nature of the thing you are seeing. ... We can't literally see down there." [p. 90]
• "The atoms remain discrete entities, distinct particles composed of protons and neutrons in the nucleus, a huge amount of hollow space, and a cloud cover of electrons located far, far away from the nucleus." [p. 91]

This latter description of the atom, with a huge amount of empty space between the nucleus and the electrons, is new to me!