Do any astronomers believe the Earth is flat?
In February 2018 I spent some time searching for professional or amateur astronomers who are flat-earthers. I didn't expect to find many but given the very large number of astronomers in the world, and knowing that some of them have very eccentric ideas indeed, I did hope to find at least a few examples worth looking into.
I found a few collections of articles and papers but nothing worth reporting. In short, I can't find any flat-earth astronomers. Even historically, every notable astronomer, going right back to Aristotle (384–322 BC), has worked with a globe-earth model.
Why isn't there a single astronomer who thinks the Earth is flat? Professional astronomers argue about lots of things and there are plenty who support "fringe" theories and alternative cosmologies. In amateur astronomy circles there are many disagreements over topics from the big bang to climate change to evolution. But for all the controversies and radical theories, the flat-earth theory is one idea that has never been embraced by either professional or amateur astronomers.
Flat-earthers offer two possible explanations for this: Either astronomers are part of the globe-earth conspiracy, or astronomers honestly believe in a globe-earth but they are mistaken.
The first argument will be dismissed by anyone who has dealt with the astronomical community. It isn't plausible for the world's astronomers to be colluding in such a fashion. If you're unconvinced, I encourage you to spend some time with astronomers at your local astronomical society. It shouldn't take long for you to realize that the conspiracy idea is unrealistic.
The second argument is the one most flat-earthers go with, i.e. astronomers are misinterpreting their data when they say the Earth is round. This argument is problematic when you consider its scale and the consensus that has survived thousands of years across cultures from all over the world. It's highly unlikely that every single astronomy professor in history is wrong, while a small group of people with no qualifications or practical experience is right1. It's more likely that the qualified people are right, especially when you consider the next point...
In my experience flat-earthers don't know much about astronomy. I've dealt with hundreds of them and so far I've never met one who really knows the positions and movements of celestial objects as seen from Earth. Sometimes they claim a rudimentary understanding, and there are plenty of YouTube videos in which flat-earthers talk about astronomy, but none of them demonstrate the kind of knowledge that you'd see at an amateur astronomy club.
This is an important point because the first requirement of any cosmological theory is this: Does it match what we see? If it doesn't, it fails. But if you don't even know what we see in the sky, how are you testing your theory?
The flat-earth theory does not match what we see in the sky. Astronomers know this.
Flat-earthers do have some generalized answers to explain what we see in the night sky. For example, flat-earthers explain the different positions of constellations as a result of changing perspective. However perspective means that an object appears to get larger as it approaches and smaller as it recedes. Constellations do not change size as they change position—they stay the exact same size, meaning they are not approaching or receding. Flat-earthers counter this with increasingly bizarre explanations ranging from atmospheric conditions to giant mirrors in the sky (seriously, I've seen that argument).
To an astronomer, the idea that the movement of constellations is caused by perspective is not something to take seriously because it is so completely different to what we observe.
It's worth noting that astronomy apps use software based on a globe-earth model. These apps show the positions of stars and planets from any point and time on Earth, and they work reliably. Conversely, no one has been able to create a simple flat-earth map of the sky, much less software based a flat-earth model.
Summary
The reason astronomers don't believe in a flat Earth is that once you know the positions and movements of celestial bodies, you realize that what you're seeing is incompatible with any flat Earth model. Flat-earthers don't know the night sky well enough to understand why no flat Earth model could ever match what we see.
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Author: Dave Owen
Footnotes
[1] You might be tempted to call this an "appeal to authority" logical fallacy but we're not relying on a small group of qualified authorities, we're relying on the collective findings of the entire scientific community.