Tuesday, August 16, 2016
Introduction
Some questions that many of us have throughout our lives, from when were children to when
we will become very old:
1.) Where do we come from?
2.) What happened before humans came on the earth?
3.) Where do stars come from?
4.) Are there others like us out there?
Tuesday, August 16, 2016
Answers to these questions found in:
1.) Myths
2.) Creation stories
3.) Philosophy
4.) Religions
This course: Look at the present-day story of creation thought to exist by many scientists.
Progression goes through
1.) Big Bang
2.) Formation of elements in stars
3.) Formation of Solar system
4.) Evolution of a part of the solar system, the Earth, whose conditions allow the
formation of life and how this life can affect the world.
Preliminaries before starting:
1.) Order of magnitude
a.) Relating to distances
b.) Relating to time
c.) Things that look similar can have many orders of magnitude difference.
(Langmuir, Charles H. and Wally Broecker. How to Build a Habitable
Planet. Princeton University Press. 2012.)
Tuesday, August 16, 2016
2.) Scientific ways of approaching things.
a.) Reductionism
Laws that account for and explain many different things.
Once laws are understood, everything can be described and predicted
through calculation.
Understanding complex things comes from breaking them down to their
simplest parts
Approaching natural systems often reductionism does not apply. Things that
often are observed in natural systems:
(1.) Chaos (butterfly effect)
Small changes can make predictions difficult.
Common in systems that have feedback
To the extent that natural systems are chaotic, their behavior cannot
be calculated precisely, even if governing equations are known
precisely.
(2.) Self-similarity (fractal) behavior
This type of drainage pattern, called dendritic, occurs over many scales. It is possible that
the left image is a satellite photo over a large region, and the left image is a photo covering
less than 1 square meter. (photo http://www.solarviews.com/huge/earth/yemen.jpg)
b.) Systems Thinking
 Reductionism assumes that the whole can be reduced to the sum of the
parts.
 Systems thinking asserts that the whole is greater than the sum of the
parts, and that there are “emergent properties” that arise from the
whole that could never be understood or predicted from a reductionist
approach.
Tuesday, August 16, 2016
 An animal cannot be fully understood from isolated
understandings of individual cells.
 An ecosystem cannot be fully understood from an individual
plant or animal it contains.
 The solar system cannot be fully understood from
understanding just one planet.
 The universe cannot be fully understood from understanding
just one galaxy.
 Second important feature of a system is that it is in constant
movement. One observation in a moment of time cannot fully
portray what is going on. (Movement of matter and energy is
always going on).
 Basic principles of systems:
 Full significance of a system cannot be predicted from a
description or understanding of only one of its parts.
 Understanding the relationships among the parts creates an
entirely different thing than the parts themselves.
 A full understanding of a system is not possible without
watching its motion.
 The function of the system is still not evident until it is
understood in its relationship to an even larger system.
Summary: With systems, looking from the largest scale down
can show how the smallest scales relate to the
largest. However, from the smallest scale, vision
upward is very limited. This is opposite to the
thought of reductionism.