Eli5: Why do wheels look like they’re spinning the wrong way when going fast?
In: Physics
You can think of like this:
Every morning your neighbor walks their dog. You can see them from the window. They take exactly 10 minutes to walk path visible from your window, from appearing from one side to disappearing on other side.
Imagine that every morning you glance out of the window for a second and take a photo of them.
First morning you caught neighbor late, when they had almost passed your window. Let’s say, on 9th minute of their walk. You wanted to see them again, so next morning, you woke up a minute earlier and photographed them when they were about 80% done with the path behind your window.
Next morning, you glance out of the window another minute earlier, and even earlier next day, and so on.
Now you’re looking through the photos in order of taking them. What do you see on photos? Your neighbor and their dog going backwards.
Brain does same thing if the speed of moving thing is just about right. It’s “taking photos” in a way that motion appears backwards, even though it’s not. Because just like your camera or phone, it’s realizing moments of something’s position, like snapshots. Then tries to put them together. And your brain is just being logical – it was there and now it’s there, probably moved backwards. Same as with the photo example.
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