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[-] Makeitstop@lemmy.world 21 points 6 months ago

My aunt once mentioned that if the earth wasn't rotating that we'd all be crushed by gravity, and it's only the spinning cancelling out that force. I responded by pointing out that gravity is also present at the poles, where you can casually walk faster than the rotation of the earth, and yet no one has been crushed to death there. She responded that it must be something to do with the magnetic fields, and wouldn't listen to anything I said when I tried to explain the basic concept of angular velocity.

[-] sp3tr4l@lemmy.zip 4 points 6 months ago* (last edited 6 months ago)

By this logic uh, you'd be crushed to death on Mercury or the Moon as they are both basically tidally locked, and also apparently helicopters don't need blades, fence posts or pool noodles would negate gravity, because they spin really fast.

Perhaps she saw that one weird Russian experiment from the 80s that concluded that if you spin something really fast it gets lighter, and thus gravity has something to do with spinning? I have seen a whole lot of spin related anti gravity nonsense on the internet.

Many of the 'electric universe' people seem to think electromagnetism somehow plays a more important role in... what we typically think gravity does... than gravity.

Ask her if she thinks things get crushed on the North or South poles of Mars. Semi-comparable amount of mass, nearly identical rotation period, but basically no electromagnetics to speak of.

[-] Makeitstop@lemmy.world 3 points 6 months ago

Honestly, she wasn't putting that much thought into it. She was just parroting a myth that's been around for a long time, and then trying to defend it when challenged by something that didn't make sense to her by bringing up something else she doesn't understand just kind of assuming the answer is in there.

If I was actually going back and redoing the conversation, I would have asked her how many revolutions per minute it takes to keep an object in the air when tied to the tip of a rope (demonstrating if necessary) and then follow up by asking how many revolutions per minute the earth has. The myth she's spouting is enabled by people not understanding that all that speed they are citing at the equator is only part of the equation, and that they have to divide that number by the size of the earth. Reframing the question in terms of revolutions per minute makes it a lot more intuitive, since a single rpm is obviously very, very slow if you want to keep something aloft, and anyone who knows how clocks work can instantly figure out just how much slower the earth's spin is.

this post was submitted on 11 May 2024
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