Eli5: How are flies so much faster than us?
Its relativity, the plane above seems to move very slowly from your perspective, however, its moving incredibly fast.
Consider this concept, where you are the plane and the fly is the observer, from a greater distance and different reference point,you appear to move alot slower than you actually are
Readers digest covered this. I only remember the part that said to clap 4 or so inches above it and you’ll get most of them. Told a paint crew about it and had the funniest day ever! But it does work.
Their eyes are much closer to their brain, and their brain has a lot less going on… Escape, Eat, mate… More or less in that order… Makes deciding and acting more efficient
Less distance for neural signals to travel. Less mass to get moving. Plus they have a really simple brain and what you are seeing is them reacting like a reflex rather than doing complex plotting like you may be doing.
Okay, so, what you are really asking is “Why can’t I swat one?”
To swat one you are trying to coordinate a body that is millions of times bigger. Your neurons have a lot farther to travel than a fly’s as you are sending singles from your brain to your arm and fingers as well as possibly your legs if you plan to walk closer. A fly? A fly has eyes that give it a wide field of view and little hairs on its body that react to changes in air pressure. The hairs feel the pressure change, like something coming in fast towards them, it triggers a fly away reflex. You’re trying to outrace a signal that is going millimeters with a much larger body where the signal has to travel much, much further. A neuron is a neuron and yours do not move faster than a fly’s.
A fly’s body is smaller so getting it up to full speed is a lot easier and requires less energy than yours does. A fly may not be able to outrun you, but it can definitely out accelerate you in the short term.
If you want to be faster than a fly (as in swat them), the best thing to do is not trigger their reflexes until it is too late. Approach slower and bring your swatting tool closer in slow movements that don’t trigger their flight reflex or appear as a threat to their eyes. Then, when you are too close for them to clear the edges of your tool, you pounce.
You are now faster than a fly for the exact same reason that if a building lifted up from the horizon and started moving in your direction in a straight line is much easier to avoid than one that appears six feet above your head before dropping.
If you’re referring to reaction time, fly eyes can see in 360 degrees, and receive light faster than humans (meaning they basically see in slow motion and thus have faster reaction times).