| Vocademy |
Most introductory books on astronomy begin with explanations of why the Sun, Moon, planets, and stars move the way they do. They dive into the basics of orbital mechanics, gravity, and heliocentric theory, etc., assuming that the reader already has a clear sense of how these celestial bodies appear to move in the sky. However, in my experience, many people—especially those without a scientific background—don’t yet possess that intuitive understanding. For example, when I see a first-quarter Moon due south in the evening sky around sunset, I know that the full Moon is one week away and that it will be rising in the East shortly before or after Sunset. When I see a bright yellowish white star above the eastern horizon around 10:00 in the evening, where I’m not expecting to see a bright star, I know that Jupiter is making its westward journey from the morning sky into the evening sky. The average person doesn’t notice such things, much less make casual predictions based on them.
This book begins from a different place.
Rather than jumping straight to the explanations, I start by laying out the motions themselves: what an observer on Earth actually sees. The daily westward sweep of stars across the sky. The Sun’s slower march in the same direction. The Moon’s slower, shifting journey. The wandering of the planets, with their occasional puzzling loops and zig-zags. I guide the reader through these patterns as they appear to the naked eye, because that’s where the history of astronomy began—and where a true understanding still begins.
From there, we explore how early thinkers tried to make sense of these motions. We meet Aristarchus of Samos, who accurately worked out the essentials of the heliocentric model shortly after 300 BC, only to be later overshadowed by Ptolemy’s Earth-centered cosmos. We follow Eratosthenes as he utilizes simple observations and the wealth of knowledge from the Library of Alexandria to measure the Earth's circumference with remarkable accuracy.
As the book progresses, we explore more complex phenomena, like retrograde motion and the apparent changes in brightness and speed of the planets. Eventually, we meet Copernicus, Brahe, Kepler, and Newton, who brought us to the threshold of the scientific revolution, and then continue forward, chapter by chapter, through the unfolding story of modern astronomy.
My hope is that this book provides a grounded and accessible path into astronomy, especially for those who have looked up at the night sky and wondered—not just what they’re seeing, but how to even begin making sense of it all.
Let’s begin, as all astronomers once did, by simply watching the sky.
| Vocademy |