Introduction to Astronomy: Exploring Time and Space

Our Solar System

“Science starts with evidence”

How does science work?

  • The scientific method
  • Difference between Astronomy and other sciences


Astronomy is perhaps the most dynamic science with new discoveries every week, but it’s also the oldest science. Astronomy starts with observations of the night sky, millennia before the telescope was invented. Humans were looking at the motions of the stars, the planets, the Sun, and the Moon, and trying to understand what was going on. Where were these objects? What were they made up of?

Astronomy is not like most sciences because the evidence we have is often remote! However, various cultures around the world were observing the same phenomena, and trying to make sense of them without telescopes and really without any mathematical underpinnings, but just looking at the regularity of the patterns in the sky.

That innovation came from the ancient Greeks about 2500 years ago. With Pythagoras, and the ideas of mathematics, and with Aristotle, and the ideas of logic, we have the basic toolkit for doing science. Science still depends on that same basic toolkit.


One of the most exciting things about science is discovery. The fact that many important things about astronomy were never predicted by a theory or anticipated by astronomers before they made the observations, we never predicted the existence of dark energy or dark matter, or black holes. But we’ve observed these things, and we’ve observed extraordinary things in the universe that were based on surprises to people looking at the world in new ways.

The periodic table is an excellent example of patterns in nature and how science works. The first notion of a periodic table came from the Greek philosopher, Empedocles, almost 250 years ago. Empedocles came up with the idea that everything in nature, all the material substances of the earth and the atmosphere and even if human beings, were made of four essential elements; earth, air, fire, and water. The combinations of those four fundamental elements produced the diversity of the material world, that’s an extraordinary idea but it’s the basis of modern chemistry. Flash forward almost 2,000 years, and we have made a lab, doing simple experiments and drawing the skeleton of the modern periodic table. Where the associations and the properties of similar elements eventually give us the idea that those elements have physical underpinnings.

As an example from the artistic side, consider Michelangelo, who wrote poetry and sonnets and we know as a scientist and an engineer. We might imagine that an artist is imposing their will on a canvas or a lump of marble or clay, imposing a vision of what they might imagine that to be and creating it from scratch. But that’s not how Michelangelo saw it. He talked about roaming around the northern Italian towns where the marble was quarried, Carrara, and he would scramble over the hillside looking for a piece on the hillside where he saw something hidden in the rock that he could liberate through his talent. That’s an unusual view of art, that there’s something in nature in the lump of marble that he is liberating or seeing for the first time. It’s more of a scientific idea. I think a true and nuanced view of both science and art, shows that the truth is more complicated, that there is synthesis and analysis and dissection and recompiling into a hole that occurs in both fields of human endeavor.

Discovery is an important and exciting part of science. Many of the things we understand about the universe, were not predicted by any theory. There were completely unanticipated. So scientists must always be alert to patterns in nature, to something new and surprising that might lead them to a deeper understanding of the universe. This is true in art as in science. The whole idea of whether things are discovered or invented and are products of the human mind is an interesting philosophical debate that’s never been resolved.