What are the wonders in the sky that we see at night? Humans have been pondering this question since before recorded history, often giving supernatural powers to the stars and planets. Prehistoric farmers used the movement of constellations to know when to plant and harvest their crops. Early Chinese astronomers charted the paths of comets, while the heelstone at Stonehenge in England was constructed in alignment with the Summer Solstice.

The ancient Greeks first developed theories about the nature of the movement of stars and planets. Although heliocentric theories (where the Earth revolves around the Sun) had first been advanced by Aristarchus in the 3rd century B.C.E., Aristotle’s 4th century B.C.E. hypothesis that the Sun and the other stars and planets revolved around the Earth (geocentrism), later codified by Greek mathematician and astronomer Ptolemy in the 2nd Century C.E., became the foundation of the Catholic Church’s(and the West’s) belief placing the earth at the center of the universe.

Not until 1543 did the Polish mathematician and astronomer Copernicus challenge geocentrism. The Church declared heliocentrism to be heretical in 1616, setting the stage for a confrontation with the Italian astronomer Galileo Galilei, whose astronomical observations proved Copernicus correct. Galileo’s pioneering use of the telescope helped him to discover sunspots, the phases of Venus, the four moons orbiting Jupiter and the mountains on the Moon. His findings fundamentally weakened the Ptolemaic theory and theological ideas placing humans at the center of the universe. In 1633, the Church’s Holy Inquisition judged Galileo “vehemently suspect of heresy,” and forced him to recant his views and spend the remainder of his life under house arrest.

Although persecuted in his own time, Galileo’s ideas later became the basis for modern astronomy, the scientific seed that ultimately led, centuries later, to the Apollo missions to the moon. Perhaps most importantly, the Inquisition’s judgment against Galileo is a lesson that scientific inquiry should not be restricted by any kind of influence from church, state or private donor, but must be based on free evidence. While the work of scientists and scholars will always reflect the larger society in which they live, that society should not place barriers in the way of knowledge.


Science & U!: Science, Technology and Outer Space

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  1. Established in 1959, the NASA History Program was created to document the history of the National Aeronautics and Space Administration.  The division's website contains a wealth of information, including images, oral history transcripts, and other primary resource materials, along with official histories.
  2. The Smithsonian's National Air and Space Museum's "50 years of Space Flight" online exhibit, provides a brief overview of the U.S. and Soviet Space Programs.
  3. In building support for the space program, President John F. Kennedy declared in 1962:  "We choose to go to the Moon in this decade and do other things, not because they are easy, but because they are hard."  The speech, delivered on September 12, 1962 at Rice University, is available in its entirety at the John F. Kennedy Presidential Library.