A simpler answer is that even if energy differentials are diminishing over
the entire Universe, they may increase locally. For example, gravity packs
energy and matter into smaller spaces, thereby creating the local differentials
in density and temperature from which stars are built. In turn, the heat
generated in stars creates new energy À ows within their hinterlands. This
is why planets are good places for complex beings such as us. (Inside stars,
however, the energy À ows may be too intense for the building of new forms
of complexity.)
Eric Chaisson has suggested a third possible source of free energy (or
“negentropy”). The expansion of the Universe itself may constantly create
new energy imbalances, ensuring that work can always be done somewhere
in the Universe! These conclusions do not contradict the second law of
thermodynamics because in the long run local energy À ows diminish energy
differentials in the Universe as a whole.
Wherever there are local energy gradients allowing energy to À ow, it is
possible, in principle, for complex entities to appear. The rest of this course
will trace the astonishing creative process of increasing complexity, a process
eventually leading to modern human societies, one of the most complex
entities we know of. In the next lecture we ask: How do we know these
things? Why should we trust the claims made by modern scienti¿ c accounts
of the past? Ŷ
Chaisson, Cosmic Evolution, Prologue and Introduction.
Christian, Maps of Time, app. 2.
Christian, “World History in Context.”
Spier, The Structure of Big History.
Essential ReadingSupplementary Reading