(edit: blah, I think this whole post is way off, and my title might be inaccurate/too sensationalist, might need to define what’s an orbit, etc…let me know helpful comments)
The Easter Bunny
The Earth Orbits the Sun
All of these are made up.
Over Thanksgiving weekend, I wanted to research the “fundamentals” I learned as a kid. You know, things that are “absolutely true”: 1+1=2, gravity pulls things down, it hurts to skin my knee. I started with “The Earth Orbits the Sun”. Of COURSE that’s true, right?
I was surprised to learn “The Earth Orbits the Sun” is wrong. No joke, it’s a misleading representation of our solar system and how physics works.
Center of Gravity of the Solar System
The Earth doesn’t orbit the Sun.
The Earth orbits the center of gravity of the solar system.
The Sun orbits the center of gravity of the solar system, too.
The center of gravity of the solar system is not inside the Sun.
An animation of a planet and a sun orbiting around the center of this minimal system (NASA)
A Helpful Diagram
This is a diagram from Wikipedia showing the center of gravity of the solar system, starting from 1945 up to 1994. The light yellow is the sun, and the dark yellow is the nucleus of the sun. As you can see, the center of gravity of the solar system moves around a lot. It isn’t always inside the sun.
The chart only goes to 1994, so I’m not sure where the center of gravity of the solar system is today, but as of 1994 it was about 400,000 miles from the surface of the Sun.
Motion of the Solar System barycenter relative to the Sun (Wikipedia)
Anyway, it took about 20 minutes to research all of this. And I took something that I thought was a fact, and learned something better. Kind of a fun experience.
“OK, Tito” you say, “I get what you’re saying, it’s inaccurate. But it doesn’t really matter. It’s close enough to say that ‘the Earth orbits the Sun'”
You’re probably right. But here’s 2 thoughts I had on why this is more important than you might think.
1. On “Scientific Knowledge As Superiority”
(Or “Even NPR Has Ego”)
Now you see, this idea the Earth goes around the Sun is incorrect. Our solar system rotates around the center of gravity of the entire solar system. Yes, the Sun is the most massive object in our solar system. But that doesn’t mean it’s the center of gravity. If the Earth goes around the Sun, then by that same token, the Earth goes around Venus, and really, the Sun goes around the Earth too.
But here’s the problem. Often, we take the science we “know”, and we lord it over people that aren’t in the know. The National Science Foundation (NSF) surveyed Americans. One of their questions was:
Does the Earth go around the Sun, or does the Sun go around the Earth?
You know what my answer would be…”both”
The Results are in…NPR.com: 1 In 4 Americans Thinks The Sun Goes Around The Earth, Survey Says
1 in 4 Americans Thinks The Sun Goes Around The Earth – NPR
“haha” we’re supposed to say, “what idiots other people are!”
Or “Oh no, gosh America is going down the tubes”. “Stupid people shouldn’t be allowed to have babies”, reads the bumper sticker on your car.
Don’t get me wrong, I don’t think these survey results are positive, and better public education about science is a big opportunity. But I think NPR’s reaction points out a pressing cultural problem. Using scientific knowledge as a way to hold ourselves above others is a deep societal issue.
Especially when we clearly haven’t done the research ourselves.
Enough on that for now.
2. It’s a Western Way of Thinking
I want to point out that ideology is powerful. So here’s one last thought. I think the way we describe the relationship between the sun and the other planets says a lot about our culture. It seems to me that this model boils down to “The little planets follow the big sun around”. That sounds like the moral to a children’s book you would find in America. And in fact, it seems like a cornerstone of western society. Now instead think about this, “All the planets rotate around each other, even the massive sun is pulled by the smaller planets”. That sounds like something that would be written off as “hippy” or kind of “zen”.
I’d love to find out what metaphors and diagrams more Eastern cultures use to explain the physics of our solar system. How do they explain this in China or Japan?
References I Found Helpful
- ZidBits.com – The Earth Doesn’t Actually Orbit the Sun?
- Science Questions with Surprising Answers – Why did people believe the Earth is the center of the solar system when it’s obvious the sun is?
First sentence: “The sun is not the center of the solar system.”
- The scientific word for this “center of gravity” is the barycenter (Wikipedia) of the solar system, in case you like jargon. Barycenter – on Wikipedia *I never like when textbooks start out with jargon and acronyms before explaining anything. My motto — use long form 10 times and then introduce jargon. i.e. The first thing you need to know about DNA is that it encodes genetic instructions NOT that it stands for “deoxyribonucleic acid”, but most textbooks mess this up.
- Now, what about the Earth being flat? I checked that out, too. It looks spherical to me.
- Hmm, but what about atoms? Supposedly everything “orbits around the nucleus”. I wonder what the barycenter of an atom is.
- I hope my blog post doesn’t have that tone of “I know something, and you don’t, and you’re stupid”. But it easily could. I tried to make it as eye opening as possible without getting everyone defensive.