Saturday, April 23, 2016


Galileo's Dialogue Concerning the Two Chief World Systems, published in 1632, compared the staunchly held Ptolemaic system with worldview changing Copernican theory.

Ptolemaic systemThe Universe orbits the Earth
Copernican systemThe Earth orbits the Sun

By 1633 Galileo's Dialogue Concerning the Two Chief World Systems had been put on the Index of Forbidden Books. Commissioned by Ferdinando II de' Medici, Galileo's book was banned because it was "vehemently suspect of heresy".

From the 21st century, this 17th century heresy is a mere historical footnote. Acceptance of the Copernican system marks a plot point in an evolving narrative forming a fundamental human-centric existential construct.
If you could see the earth illuminated when you were in a place as dark as night, it would look to you more splendid than the moon.
— Galileo Galilei

Earth viewed spacecraft circling the moon
source: NASA Lunar Reconnaissance Orbiter

Human space travel has caused new figurative and literal perspectives of Earth.
It's tiny out there… it's inconsequential. It's ironic that we had come to study the Moon and it was really discovering the Earth.
William Anders, Apollo 8, When We Left Earth: The NASA Missions
One's worldview, the prevailing human-centric existential construct, is updated in fits and starts as we reconcile new information.