Thirty years of the Galileo spacecraft

Image by NASA – Public Domain.

Thirty years ago this week, the Galileo spacecraft arrived at Jupiter and became the first to orbit an outer planet. It deployed a probe which entered the Jovian atmosphere then orbited the planet 34 times, closely encountering a number of Jupiter’s moons. Its legacy led to a better understanding of this gas giant’s atmosphere, evidence that liquid oceans exist under the moon Europa’s icy surface, and spectacular observations of volcanic activity on another moon, Io.

The spacecraft was named after Galileo Galilei, who through his homemade telescope in January 1610 observed four moons orbiting Jupiter. He published this finding a couple of months later in his book The Starry Messenger. This was a significant moment in modern science. Together with other observations of the surface of the Moon and the phases of the planet Venus, it clashed with the dominant view of Aristotle of an Earth-centred universe. Rather, it supported the Copernican model that all planets, including Earth, were in orbit around the Sun.

In what became a long-running struggle between Galileo and his own Roman Catholic Church, resulting in his extended house arrest, a number of commentators claim that this marked the beginning of science freeing itself from the shackles of religion. Yet as many historians have pointed out, the history is far more subtle and interesting. Many leading Christian contemporaries such as the Puritan Bishop of Chester, John Wilkins, were strong advocates of the Copernican model.

The clash was not between the Bible and science, rather it was focused on authority and how you “did science”. The great theologian Thomas Aquinas had adopted Aristotelian philosophy as a way of articulating the Christian faith, and this brought with it not only an Earth-centred solar system but also an emphasis that human logic was supreme in working out the nature of the Universe. But fellow Christians such as Galileo saw science differently. Arguing that the God of the Bible was free to create however God wanted, not constrained by human logic, the most important part of science was therefore observation. So, in a sermon in 1614, Tommaso Caccini attacked Galileo with a clever wordplay on Acts 1:11 saying, “You man of Galilee, why stand gazing up into heaven?”. Yet for Galileo, God had given the gift of starry messengers by which we could understand the universe.

The Galileo spacecraft would travel 2.8 billion miles and cost $1.39billion in its journey to and around Jupiter. Some will question whether it was worth it. I always want to take seriously how funding for science has to be balanced with other priorities in the world, but there is something in human curiosity about the universe that Christians will want to affirm. And if Christmas spending is estimated to be around £42 billion in the UK alone, then perhaps a small part of human wealth could be spent on exploring the universe.