>>Chapter 10: Sailing, Shakespeare and insurance>> <<Chapter 8: Where in the world is Dr. Ryan Stone?<<
School is just too hard
How are you today, my young alien friends? Still not great? Because you’re never going to understand physics, biology or the causes of the Second World War? But all we do together is talk about physics and biology, history and geography, and probably some chemistry, some maths, and a few other difficult subjects as well, and you don’t have trouble following me, do you?
How long does it take to understand stuff?
I must say, I really don’t understand how they present some topics in your school textbooks, as if it took five minutes to discover and understand things. For example, it took us at least 300 years to understand enough about electricity to use it (although we had been wondering about it for thousands of years), it took us at least 2,300 years for everyone to agree that it’s the earth that orbits around the sun and not the other way round, and it took us hundreds (if not thousands) of years, since people first started to ask themselves questions about the wind, to understand things like prevailing winds, and the relationship between wind and deserts. And yet your teachers expect you to understand and remember these things immediately.
“Who wants to know?” A useful question to start your research into something difficult
A question I sometimes ask myself when I’m trying to understand a difficult subject is, “Who wants to know?”
What I want to know is, who would benefit from knowing about the subject I’m trying to understand? Who cares how the wind works? Or why the winds blow in the directions they blow in?And why some winds always blow in the same place, in the same direction, at the same time of year?
One answer is sailors. There have always been boats, and people in boats have always been very interested in the weather. A bit of rain and wind which is no big deal on land can mean big waves and drowning if you’re on water. And while days with no wind aren’t a problem for us on land, it could mean your sailing boat being stuck in the middle of an ocean for days, and sometimes weeks, and dying of hunger and thirst.
When we started doing serious long-distance sailing: The Age of Sail
About 500 years ago, during The Age of Discovery, which was also known as The Age of Sail, because there would have been very little discovering without sailing, people figured out how to build ships that could travel across oceans to unknown continents, and back again.
Why hadn’t ocean-sailing ships been invented before then? That’s an excellent question. Maybe because sailing across oceans was so dangerous you had to be out of your mind to consider it. Or maybe because until about 500 years ago we still thought that the sun and all the planets moved around the earth. This meant that our maps of the stars were not very accurate.
When you’re at sea, how can you know where you are?
When you’re in the middle of an ocean, there are no mountains, road-signs or monuments, and the only things that can help you guess which direction you’re going in, and where you might be, are the sun, the moon, the planets and the stars. For, example, if you can see the North Star, you know wh you are in the northern hemisphere because you can’t see it from the southern hemisphere. Today every smartphone has GPS, which can tell you exactly where you are, wherever you are. But we’ve only had GPS for about 20 years, and before then, navigating – figuring out where you are – was done with the help of charts of the stars. We needed the telescope to be invented to understand why the stars move around the way they do, and to help us make useful maps of the stars, which made sailing around in our oceans possible.
Galileo Galilei: the first to show planets orbiting around the sun
Then, about 500 years ago, the Italian scientist Galileo Galilei came along. He wasn’t the first person to say that Earth orbits around the sun, but he was the first person to build a telescope powerful enough to look at how the planets move and start to show that the Earth moves around the sun.
With his powerful telescope Galileo could see four of the planet Jupiter’s moons. Moons orbit around planets, and with his telescope you could see that these moons weren’t orbiting around Earth, but around Jupiter. He could also see that the planet Venus was moving around the sun and not the earth. He could see for the first time that the way the planets moved around in the sky could only be explained by the earth moving around the sun, together with all the other planets.
Galileo vs. the Catholic Church
At that time, suggesting that the earth wasn’t at the centre of the universe would get you into big trouble with the Catholic church, and when Galileo announced what he had discovered he was arrested by the Spanish Inquisition, a kind of police force for the Catholic Church, and forced to tell everyone his ideas were wrong, and was imprisoned for the rest of his life.
They say that when Galileo tried to make the officers of the church look at the moons of Jupiter through his telescope, they refused, saying that the Devil (an evil being who, according to many religions, is responsible for everything bad) was capable of making anything appear in the telescope, so it was best not to look through it.
Good stories vs. truer, but less exciting stories
At least, that’s one version of what happened. It’s a great story, but things probably didn’t happen that way. We love stories, especially ones where there are good guys and bad guys, in this case Galileo, the misunderstood genius, against the big, bad Catholic Church. About 70 years ago, a German writer called Bertolt Brecht took the story of Garibaldi, improved it by changing a few important details, and turned it into a dramatic play. And now, this story is what our teachers teach us about the history of Garibaldi’s discoveries in our schools.
A battle of ideas: Geocentrism – the sun goes around the earth, vs. Heliocentrism – the earth goes around the sun
So, this is what probably happened, and this is what often happens when you make a new scientific discovery, and why scientific progress has often been slow and hard. The first person in Europe who tried to say that the earth moves around the sun was Aristarchus, from Ancient Greece, and he said it about 2,400 years ago. However, Aristotle, the much more famous ancient Greek, had argued more convincingly, one hundred years before, that the earth is at the centre of the universe, and everything moves around it.
Aristotle: world champion of everything, especially arguing
Aristotle had a lot to say about a lot of different things, including physics, biology, psychology, philosophy, and politics. They say that no-one has ever known as much about so many different things as Aristotle. Aristotle was also an expert in rhetoric, which is the study of how to argue. Aristotle was very good at arguing. This is important, because if you are a scientist and you have an amazing new scientific idea, but you can’t convince people you’re right, then your idea won’t get very far.
The main problem with Aristarchus’ ideas was that they were based on the belief that everything was made of four elements: water, earth, wind and fire. Aristarchus believed fire was the most important of the four elements, and the centre was the best position be in, so the sun, being pure fire, had to be at the centre of the universe. Aristotle’s ideas were based on what he could see in the sky: the sun, moon and stars passing overhead as if they were stuck onto an invisible globe spinning around the earth. Aristotle’s ideas were more convincing and were believed for more than 2,000 years because they were based on the observation of things that everyone can see, and because, although they didn’t explain everything, they made sense. Whereas Aristarchus’s ideas sounded crazy.
Aristotle was wrong, but he was being scientific about it
Aristotle was using the beginnings of a scientific method, whereas Aristarchus was basing his ideas on beliefs. If you’re a scientist with an important idea or discovery, you need to do three things for your idea or discovery to be taken seriously.
- First of all, you need to show your idea is right, because it’s based on things you, and everybody else, can see and test.
- Secondly, your idea must be useful. It must give us more answers than previous ideas, to all our questions about the way things work.
- Thirdly, you need to convince all the other scientists around that your idea is best, which usually means convincing them that their ideas are wrong. That’s probably the hardest part.
Does your discovery help us answer questions? Or does it make you ask a whole lot of new, more difficult questions? Can you answer those more difficult questions?
Aristotle’s ideas made explaining day and night easy: the sun rises, moves across the sky and when it goes down on the other side, it’s dark. On the other hand, if the earth rotated around the sun, it would also have to be spinning on its axis to explain day and night, and you can see that we’re not all flying off into space, are we? If the earth were spinning on its axis, how do you explain why things fall straight down to the ground, but fire goes straight upward? If we’re spinning so fast, why isn’t there a strong wind all the time? Ridiculous!
Without a telescope to get a closer look at the planets and the stars it was difficult to start answering these questions. And even when Galileo came along with his telescope and got a closer look, he still couldn’t answer all these questions to the satisfaction of the scientific community. Galileo’s ideas didn’t satisfy either the church, which at the time was encouraging scientific discovery by building and running most of the schools and universities, or other scientists, because he couldn’t answer these and other questions, and so, couldn’t prove that the sun goes around the earth. He was probably put under house arrest because while he was arguing his ideas, the Pope, the leader of the Catholic Church, thought Galileo was making fun of him. It’s never a good idea to annoy powerful people.
Standing on the shoulders of giants …
On the bright side, Galileo made a lot of money from selling his telescopes to sailors and helped start the Age of Sail. And 80 years later when the English scientist Isaac Newton was presenting his work explaining gravity, which was immediately accepted, he said, “If I have seen further, it’s because I was standing on the shoulders of giants.” He was saying that his discoveries wouldn’t have been possible without the scientific thinking of people with gigantic brains like Galileo.
No I haven’t got around to telling you about the winds yet, have I? That’ll be for next time.