Over 400 years later, Galileo’s observations of Jupiter and its moons are easy to repeat.<\/p>
And that\u2019s something you can easily achieve when Jupiter is at opposition<\/a> and well-placed in the evening sky.<\/p> For help with this, read our guide on how to observe Jupiter through a telescope<\/a>.<\/p> If you don\u2019t own a telescope, get in touch with your local amateur astronomy society<\/a> and see if they are hosting any observing events where you can join in.<\/p> Into DIY? Find out how to build your own Galileo telescope<\/a><\/em><\/strong><\/p> Galileo\u2019s observations of Jupiter led him to realise that the four points of light dancing around the distant world were in fact\u00a0 the planet\u2019s four largest moons, now called the Galilean moons<\/a>. <\/p> In this way, what Galileo observed at Jupiter marked a huge change in scientific thinking.<\/p> Before Galileo, humanity viewed the Universe according to a model put forward by a Roman astronomer and mathematician living in Egypt in the 2nd century AD.<\/p> Claudius Ptolemy\u2019s work the Almagest put Earth at the centre of the known Universe and the Sun, Moon and planets in orbit around it, while the stars were fixed points in space.<\/p> This Ptolemaic view of the Universe prevailed for hundreds of years, backed up by the Christian Church, since it supported religious views so conveniently.<\/p> Earth was the creation of God, so naturally He would place His great creation at the centre of the Universe to confirm humanity’s favoured place in the heavens.<\/p> Galileo was already certain that this view of the Universe was wrong: he had seen phases on Venus and the shadows of mountains on the Moon<\/p>Galileo, Jupiter’s moons and heliocentrism<\/strong><\/h2>
![\"Ptolemaic](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2023\/11\/GettyImages-92845823-1024x754.jpg?fit=800%2C589\")
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