7 ms·
In zero-g there is no such thing as "landing on your feet" because there is no such thing as "landing". There is no "down" direction so of course cats can't det
by pdonis 5y ago
In zero-g there is no such thing as "landing on your feet" because there is no such thing as "landing". There is no "down" direction so of course cats can't detect something that doesn't exist.
- miked85 5y agoNever underestimate cats.
- lgessler 5y agoThat's certainly the intuition most people would have about this, but it's still interesting to see it borne out when in principle there could have been other, surprising signals that cats respond to in order to right themselves.
- pdonis 5y ago> That's certainly the intuition most people would have about this Actually, though, it's wrong. See my responses to others elsewhere in this thread.
- throwawayben 5y agozero-g is the same as falling though, just with no apparent acceleration.
- nemothekid 5y agoI've never thought critically about this - but in free-fall on earth, you are falling through the air which could be used to measure the direction of the fall.
- ndr 5y agoIs it? What about the resistance of air that was not going at your own speed?
- dfxm12 5y agoAcceleration is a vector. A vector is magnitude and direction. "Down" is a direction. If there's no acceleration, there's no "down". That there is no acceleration in "zero g" is a critical difference between "falling" and "zero g" in this context. Therefore, they aren't the same.
- pdonis 5y ago> Acceleration is a vector. True, but which kind of acceleration are we talking about? A cat in the "zero g" in the experiment described in the video has no coordinate acceleration relative to the Earth. Whereas a cat falling off a ledge to the floor does have coordinate acceleration relative to the Earth. But both cats have zero proper acceleration--they are both weightless. (Air resistance will become significant at some point during a fall from a height to the floor, but cats are heavy enough that I don't think that would be significant in most falls where cats are observed to land on their feet.) And "zero g" means zero proper acceleration, not zero coordinate acceleration. So the GP is correct and my original comment was in error: cats in both situations are in "zero g" so that can't be what is causing the different behavior in the two situations.
- mrexroad 5y agoI think most people would consider “falling” to be going “down” a gravity well. Stable orbits around a gravity well, or at sufficient distance to not be influenced by it, are not what most would consider to be “falling.”
- jameshart 5y agoBut that’s a misunderstanding. Stable orbits are free fall. There is no such thing as a stable orbit “at sufficient distance to not be influenced by” gravity. There’s no such thing as a sufficient distance.
- e_y_ 5y agoI think more precisely, the traditional definition of an orbit (stable or not) is that it's influenced by gravity. You could be in a situation where the influence of gravity was negligible (say, far beyond any galaxy) but it wouldn't be considered an orbit at that point. I guess certain multi-body situations like Lagrange points might make it debatable about which "direction" you're falling though.
- sacrosancty 5y agoI agree with mrexroad. Falling implies downward velocity. Free-fall is a different term that implies downward acceleration. For example, a ballistic projectile fired up that then falls back down first climbs, then falls, but it is in free-fall the whole time.
- pdonis 5y ago> Falling implies downward velocity. Free-fall is a different term that implies downward acceleration. The GGP didn't say zero-g "is" falling. They said it's "the same as" falling. Which, for purposes of this discussion, it is, for the reason I gave--the key common property is being weightless, i.e., free falling. Note, btw, that "free-fall" does not necessarily imply "downward acceleration". It just means "weightless". You could be weightless, in free fall, far out in deep space well away from all gravitating bodies, so that there is no well-defined notion of "downward acceleration" in your vicinity.
- Rygian 5y agoIf there's no rushing wind tingling your hairs, then it's not the same.
- sdeframond 5y agoNext : dropping a cat in 0g in a wind tunnel
- tomxor 5y agoPretty sure this was a low effort excuse to play with cats in zero-g... and who could refuse :D
- kadoban 5y ago> who could refuse Anyone who has "played" with cats in unfamiliar circumstances, like a bathtub. I hope they wore their chainmail.
- tomxor 5y agoGood point, although as long as they are not in contact with any surfaces it seems pretty safe... Until they figure out how to propel themselves, which would be gross.
- lisper 5y agoThe problem with that theory is that while a cat is falling it is in zero G. It actually makes an interesting puzzle to figure out what a cat is actually responding to when it lands on its feet after a fall.
- screye 5y agoThat is only true in a vacuum though. The cat is feeling the air resistance locally on the parts that face forward while G is applied uniformly.
- lisper 5y agoThat's one possibility but I'm pretty sure that's not it. If it were, then if you dropped a cat in a stiff breeze it would land sideways.
- bhedgeoser 5y agoDo they?
- tailspin2019 5y agoThere's only one way to find out...
- throwanem 5y agoI'll bring the cat if you'll bring the wind tunnel!
- pdonis 5y ago> The problem with that theory is that while a cat is falling it is in zero G. Ah, yes, I see your point. Air resistance would eventually kick in and provide positive G, but not in a short enough fall. And cats are heavy enough that "a short enough fall" probably includes most falls in which they are observed to land on their feet.
- sophacles 5y agoI'm pretty sure the enemy gate is down.
- Urgo 5y agoYes, this!
- mrtweetyhack 5y ago
- fullstop 5y agoIn The Expanse books they made a point of showing that the inners (earth / mars) had difficulty with zero-g combat because they would try to lean back into corners and inadvertently push themselves out into the open.