Prologue

"There is talk of a new astrologer who wants to prove that the earth moves and goes around instead of the sky, the sun, the moon, just as if somebody were moving in a carriage or ship might hold that he was sitting still and at rest while the earth and the trees walked and moved. But that is how things are nowadays: when a man wishes to be clever he must . . . invent something special, and the way he does it must needs be the best! The fool wants to turn the whole art of astronomy upside-down. However, as Holy Scripture tells us, so did Joshua bid the sun to stand still and not the earth." 

 - Martin Luther, 1539  

Heliocentrism - like many of the ideas behind human progress - was opposed by religious fundamentalists of the time. But despite Luther's concern in 1539, Aristarchus of Samos (310 - 230 BCE) had first proposed a heliocentric model and suspected stars were other suns and very far away. He also appears to have recognized that this fact would explain why there was no observable stellar parallax (before the invention of the telescope). Pliny the Elder and Seneca also referred to retrograde motion of the planets as an apparent (and not real) phenomenon, but better theories and evidence for this speculative, revolutionary, and counterintuitive idea would have to wait for Galileo and the invention of the telescope and Luther's "new astrologer" - as well as Brahe, Newton, Kepler, and others.

There are many reasons why our society is so anti-science today and why some claim that we are living in an "Age of Magic," but religious fundamentalism continues to be a factor in debates about evolution, climate change, women's health care, and many other issue of public interest.  Chris Mooney, reporting on a paper published in the journal Social Forces in 2015 by sociologist Gordon Gauchat of the University of Wisconsin-Milwaukee, notes that "being a biblical literalist — endorsing the statement, 'The Bible is the actual word of God and is to be taken literally, word for word' — was a much bigger factor than liberalism or conservatism in explaining why some people disagreed with the use of science in 'concrete government policy decisions,' and also why they were against federal science funding."

When science is discounted based on ideology, we all lose. But when science is accepted based on authority or tradition, instead of critical thinking and evidence, we also lose. We must be both skeptical and open to new ideas and experiences to make progress. And as Richard Feynman said, "The first principle is that you must not fool yourself – and you are the easiest person to fool."

So...with that said, how would you prove heliocentrism to a skeptic?

And no, this is not an open (or memorized) book test...

Luther Bible, 1534 by Torsten Schleese, Public Domain.