[HN Gopher] Cats in zero-g lose their auto-righting reflex (2011...
___________________________________________________________________
Cats in zero-g lose their auto-righting reflex (2011) [video]
Author : carabiner
Score : 131 points
Date : 2022-04-11 15:57 UTC (7 hours ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| Steltek wrote:
| I feel like there was an indirect experiment here: how quickly
| defenseless humans can be mauled by a struggling cat in an
| enclosed space.
| bagels wrote:
| Humans can reason about the physics, might have an advantage of
| efficient escape.
| balls187 wrote:
| Footage here: https://www.youtube.com/watch?v=okZW3_5Gr4s
| tyingq wrote:
| These parabolic flights give you ~25 seconds of a close to zero-g
| environment, but bookended by some pretty uncomfortable ~+-2g
| before and after periods. It would be interesting to see the cats
| in a more stable and extended zero-g environment to see how they
| adapt over time.
| pwdisswordfish9 wrote:
| A buttered piece of bread would be cheaper
| Simplicitas wrote:
| In a priori, isn't this kinda obvious ... LMAO
| xwdv wrote:
| I'm not sure what they expected? Which way is a cat supposed to
| auto-right to in a weightless environment?
| teraflop wrote:
| But a cat free-falling from a height is also weightless, and
| yet they manage to right themselves using perceptual cues. The
| point of the experiment is to see how the _behavior_ changes
| when the sensation of weightlessness is presented for an
| extended period of time, without the "falling" motion
| (relative to the perceived local environment) that normally
| accompanies it.
| ars wrote:
| This is what most of the people replying here are missing -
| all falls are "free fall" (zero g).
|
| Yes the cat manages, but not in this situation.
| NovemberWhiskey wrote:
| The cat's system has memory. The transition into free-fall
| from a state where it was previously experiencing ground
| reaction force provides a cue for the self-righting reflex
| on the direction of "up/down". Apparently even blind cats
| can self-right based on their vestibular system.
| moron4hire wrote:
| Any fall is a weightless environment, whether it's in a plane
| or off a building.
|
| But in a plane, you don't have the air rushing past your
| whiskers.
| jstanley wrote:
| The cat might use visual cues to right itself.
|
| It might have been interesting to re-run the test with a more
| obvious "horizon" and see if the cats react to that. Then if
| the cat still doesn't right itself, it seems like it is using
| acceleration rather than vision to determine which way is down.
| nealabq wrote:
| Do we know it's visual? If you drop a cat in darkness (onto a
| pillow of course), will it right itself? What if you put it
| in an elevator that accelerated downwards at 1G so the cat
| fell to the ceiling? How does it know which way is down? Is
| it the horizon, or the bright sky, or does the cat remember
| the scene before it was dropped? Or is it the air rushing by?
| cecilpl2 wrote:
| > Then if the cat still doesn't right itself, it seems like
| it is using acceleration rather than vision to determine
| which way is down.
|
| This is not possible because objects (including cats) in
| freefall do not experience the sensation of acceleration.
| smaudet wrote:
| true_religion wrote:
| Before a cat (or any object) experiences free fall, they
| experience acceleration so they know which way gravity is
| pulling them. Surely, a cat can remember what happened to
| it in the last few seconds and instinctually put its feet
| in that direction?
| throwawayben wrote:
| You don't feel any acceleration from gravity - it can
| only be determined from other senses like vision or the
| air flowing over your skin/fur
| haneul wrote:
| This is possible because in free fall on earth, there are
| directionality signals when blinded - for example, air
| resistance.
| ce4 wrote:
| Probably the same reason as discussed here recently: A naked
| skydive inspired a way to keep pilots oriented in flight
| (military.com) https://news.ycombinator.com/item?id=30959126
|
| Edit: Probably that submission led to this one.
| carabiner wrote:
| At the 28 sec mark, in the upper right one of the cats appears to
| be walking on the ceiling.
| technick wrote:
| Buttered Cat Paradox
|
| https://en.wikipedia.org/wiki/Buttered_cat_paradox
| digitalsanctum wrote:
| You had me at "cats in zero-g"
| xallarap wrote:
| gene-h wrote:
| the cat righting maneuver is a zero-angular momentum maneuver, so
| if the cat has a slight amount of spin, it is not possible for
| the cat to correct it. That may be what happens in the video
| eterevsky wrote:
| Can a cat barf from disorientation?
| progre wrote:
| Yes.
|
| Source: Have traveled with carsick cat.
| rossdavidh wrote:
| We know humans in zero-g often barf a lot, and cats often barf
| a lot, so it seems like cats in zero-g was a high-risk
| experiment.
| pdonis wrote:
| 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.
| lgessler wrote:
| That'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 wrote:
| _> 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.
| sophacles wrote:
| I'm pretty sure the enemy gate is down.
| throwawayben wrote:
| zero-g is the same as falling though, just with no apparent
| acceleration.
| nemothekid wrote:
| I'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 wrote:
| Is it? What about the resistance of air that was not going at
| your own speed?
| dfxm12 wrote:
| Acceleration 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 wrote:
| _> 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.
| Rygian wrote:
| If there's no rushing wind tingling your hairs, then it's not
| the same.
| sdeframond wrote:
| Next : dropping a cat in 0g _in a wind tunnel_
| mrexroad wrote:
| I 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 wrote:
| But 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_ wrote:
| I 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.
| pdonis wrote:
| In the sense that matters for this discussion, zero g _is_
| the same as falling--both are weightless conditions. So the
| GP is correct and my original comment was in error; "zero
| g" can't be what is making the difference.
| tomxor wrote:
| Pretty sure this was a low effort excuse to play with cats in
| zero-g... and who could refuse :D
| lisper wrote:
| The 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.
| MarkMarine wrote:
| The cat is being accelerated at 9.8m/s2 towards the earth
| while falling. What do you mean by this?
| MrPatan wrote:
| Isn't the cat also being accelerated at 9.8m/s2 towards the
| earth while in "zero g"?
| metrognome wrote:
| While falling, the cat is in an inertial reference frame,
| so it is not accelerating. The ground is actually
| accelerating upward at 9.8 m/s2, counteracting the flow
| of spacetime.
|
| This Veritasium video gives an intuitive explanation:
| https://youtu.be/XRr1kaXKBsU
| pdonis wrote:
| _> 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.
| btilly wrote:
| I'm sure that it keeps track of which direction is up with
| the same inner ear mechanism that we use for our balance.
| Given that it starts properly oriented thanks to gravity, and
| doesn't spend long falling, this gives it a good idea which
| direction is up when it lands.
|
| Spend long enough out of gravity, and it will get confused.
| As do we.
| JumpCrisscross wrote:
| Could also be the sensation of air rushing past [1].
| Curious to test the competing hypotheses--dead reckoning
| from initial alignment versus air movement--in a wind
| tunnel.
|
| [1] https://www.military.com/history/how-naked-skydive-
| inspired-...
| pdonis wrote:
| Yes, this makes sense.
| [deleted]
| sandworm101 wrote:
| Whiskers. Every cat is perfectly aware of the rapidly
| accelerating wind rushing past its head. Them they have ears
| to hear that wind. Lastly they have eyes and some experience
| with life on solid ground. They see it coming and understand
| what that means... Unlike sperm whales.
| screye wrote:
| That 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 wrote:
| That'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 wrote:
| Do they?
| tailspin2019 wrote:
| There's only one way to find out...
| throwanem wrote:
| I'll bring the cat if you'll bring the wind tunnel!
| mrtweetyhack wrote:
| JumpCrisscross wrote:
| SmarterEveryDay did a great video series exploring cats' self-
| righting mechanisms [1].
|
| [1] https://www.youtube.com/watch?v=RtWbpyjJqrU
| Melatonic wrote:
| We probably should keep cats out of space - can't have them
| spontaneously evolving into Kzinti or something :-D
| daneel_w wrote:
| Since the ability depends on motion sensing, is this really
| surprising to anyone? In other news, kettlebells lose their
| "heavy" in zero G.
| daveloyall wrote:
| Off topic: Kettlebells might lose their "heavy" in micro-
| gravity[1], but they don't lose their "massy". I first read the
| term "massy" in some sci-fi book, by Heinlein, I believe.
|
| It takes more effort to overcome the inertia of an object with
| a lot of mass than it does to overcome the inertia of an object
| with less mass. So, you can still use massy objects to work out
| in micro-gravity! Or so I've been led to believe by convincing
| fiction. :)
|
| 1: I've also been led to believe that micro-gravity is a better
| term than zero-g for the conditions experienced during free
| fall.
| unfocussed_mike wrote:
| Dear scientists, for the love of all that is good, don't repeat
| this test.
|
| Cats aren't ever going to forgive you for engineering a situation
| where they are seen to land in an ungraceful way, and there's a
| tiny chance that they will make us all pay when they evolve
| opposable thumbs.
| frederikvs wrote:
| Cats can't be bothered to evolve opposable thumbs. They have
| human staff to take care of anything that requires an opposable
| thumb, why would they bother doing it themselves?
| cpsns wrote:
| I have 3 cats with "thumbs". Believe me they're working on
| evolving them.
| tenebrisalietum wrote:
| Cats are crafty enough to both survive and plan for a post-
| human landscape, such as climate change, World War III, or
| supply chain issues driving up cat food prices.
| progre wrote:
| What? To me it looks like they _try_ to turn their bodies but in
| freefall they can 't make sense of where down is. No reflexes
| lost.
| ordu wrote:
| Yeah, those guys kept kicking or pushing cats preventing them
| to orient themselves. Cats were surprised by the lack of
| gravity, but they were not given a chance to adapt to new
| circumstances.
| itslennysfault wrote:
| I was thinking the same thing. They're still rotating the way
| they normally would. Toward the end of the video the orange cat
| floats "up" from the floor toward the ceiling and turns it self
| around to "land" on the ceiling feet first.
| hosh wrote:
| Poor cats. It looks like they are completely outside the
| parameters of their instinctual movements.
| arwhatever wrote:
| Am not surprised that zero G severely disorients them, already
| knowing how a much a simple piece of tape disorients them. :-)
|
| https://youtu.be/mdBegLNE6OU
| KarlKemp wrote:
| This is the sort of experiment the biologists I know come up with
| towards the end of a long night.
| engineer_22 wrote:
| ->Cats in zero-g lose their auto-righting reflex
|
| Same for humans.
| alex_young wrote:
| What was the zero-g cat dropkick at the end about? Seems pretty
| unethical. https://youtu.be/O9XtK6R1QAk?t=29
| syllospri wrote:
| That's not what a dropkick is. In a similar way to someone else
| pushed a cat, the man used his foot to move the cat away from
| the floor, but because of the zero-g, it caused the cat to move
| to the ceiling. Hardly unethical.
| kazinator wrote:
| When a cat is in free fall, that _is_ weightlessness. At least
| initially, until air resistance starts limiting the velocity.
|
| In zero-g, you do not directly sense in which way gravity is
| pointing.
|
| Probably, under the conventional free fall situation, the cat is
| relying on visual clues, and the sensation of air moving through
| its fur, to establish which way it is falling, as the basis for
| the righting reflex: which way to aim the paws. Those clues are
| absent in the simulated zero-g environment, which feels like free
| fall, but the cat doesn't see any relative movement to anything,
| or feel any air movement.
| floxy wrote:
| >the cat is relying on visual clues
|
| That should be pretty easy to test. Anyone know if blind cats
| land on their feet? If blind cats are in general too geriatric
| to test on, what about a blind fold, and dropping your cat
| upside-down on a bed?
| aidenn0 wrote:
| So maybe repeat the experiment, but with a giant fan?
| geenew wrote:
| Could you accomplish the same thing in a ground based lab
| with a fan blowing air up at ~80 degrees? If airflow is used
| for orientation, then the test subject should orient to be
| parallel to the direction of airflow as it is falling.
|
| All for Science, of course.
|
| (The 80 degrees thing is there so they don't hurt themselves
| when they reach the ground - hopefully being only 10 degrees
| off vertical will be recoverable).
| someweirdperson wrote:
| Don't forget to shave the cats before conducting the
| experiment.
| kazinator wrote:
| Then, separately, experiment with LCD or projector screens
| simulating motion, and then the two in combination.
|
| (Remembering to reset the cats to initial values of the
| feline parameters before each attempt, or else using freshly
| allocated cats.)
| PaulHoule wrote:
| I'd like to take a cat to a space station like they did in some
| Heinlein books.
|
| One would think they'd learn to deal with weightlessness better
| if they had a few weeks to get used to it rather than a few
| minutes on a plane.
|
| Don't know what you'd do for the litter box though.
| MisterTea wrote:
| > Don't know what you'd do for the litter box though.
|
| dear god... the image of a regular litter box in zero G made me
| wince. I had a cat years ago who was an excavator and make a
| big mess whenever she went on archeological digs.
|
| Another thought, cats typically bolt from the litter box after
| pooping (one guy I have does an amazing 90 degree wall kick-
| walk ninja move to run downstairs.) Not happening in 0G :-)
| pkdpic wrote:
| > Don't know what you'd do for the litter box though.
|
| pray
| PaulHoule wrote:
| I thought about picking up the turds with gloves, wondered
| what I'd do about the urine, or what I'd do if the stools
| were loose and then I thought "are cat diapers a thing?" and
| it is available COTS
|
| https://barkertime.com/designer-cat-diapers/
| Buttons840 wrote:
| Has an animal without "grabbing appendages" ever been in space?
| What did it do?
| Symmetry wrote:
| Tadpoles have been:
|
| https://www.newscientist.com/article/mg14519690-700-space-
| fr...
| leshow wrote:
| Yep, from fruit flies, dogs, mice to fish:
| https://en.wikipedia.org/wiki/Animals_in_space
| jxy wrote:
| You can probably put a few mice in a centrifuge of 1 meter and
| they would be happy. Make the centrifuge 10 times larger, we
| can fit a litter box.
| gnu8 wrote:
| This sounds like a worthy experiment. Why don't we already
| have a mouse artificial gravity habitat on the ISS?
| cecilpl2 wrote:
| > Don't know what you'd do for the litter box though.
|
| Cat diaper?
| Jaruzel wrote:
| However, Heinlein cats also walk through walls - not good when
| space is on the other side.
| qbasic_forever wrote:
| Judging by how my cat can disappear and reappear at will all
| around my place... I wonder if household cats already have
| that ability.
| jimmygrapes wrote:
| Pixel walks through walls because nobody explained that it
| can't be done, so I imagine the same would apply for
| breathing in and staying pressurized in a vacuum
| rdl wrote:
| My plan is to go to Mars with the first domestic pet cat; it
| implies a level of civilization/comfort/safety (to be able to
| have pets) which is consistent with what I'd want myself. Maybe
| 10k people? 50k? Hopefully I live that long.
| roywiggins wrote:
| Shackleton's ill-fated antarctic expedition had a cat, so
| maybe not as much of a guarantee as you'd think...
|
| https://en.wikipedia.org/wiki/Mrs_Chippy?wprov=sfla1
| PaulHoule wrote:
| Ocean ships have rats so they would tend to have cats even
| if people didn't encourage them.
|
| With the COTS technology of cat diapers I think they could
| have a pet cat on the ISS but they don't want the risk that
| it goes wrong and they'd have to put it down.
| rtkwe wrote:
| There's also the smell, by all accounts the ISS already
| smells a little bad from decades of BO and grime, I would
| not want to add the smell of cat shit to that.
| jarofgreen wrote:
| And loving pet owners will want to note it did not end well
| for the cat
| qbasic_forever wrote:
| Every major sea voyage of the past had a cat or two, they
| were necessary to keep rats from eating all the food
| supplies.
|
| Apparently the cat on board the expedition that discovered
| New Zealand immediately upon reaching land jumped out and
| grabbed a small flightless bird (then a brand new species
| discovery) and dragged it on board to eat.
| aspenmayer wrote:
| Cats have been a menace to the native kiwi birds ever
| since.
| qbasic_forever wrote:
| Cats can be trained to sit on and use a human toilet seat. A
| space toilet with a vacuum would be more challenging but I bet
| a dedicated animal behaviorist with enough time and training
| could get a cat used to using a space toilet.
| nicwolff wrote:
| Not if it sounds anything like a terrestrial vacuum cleaner -
| cats do _not_ get used to those.
| FlyMoreRockets wrote:
| It may just be easier to design a zero G litter box. A screen
| bottom with a coarse granular material and sufficient airflow
| through the bed could work. No idea how a cat would dig in
| zero G though.
| throwanem wrote:
| Sturdy screening to give claws a grip would probably serve
| as the equivalent of human handholds just generally. I
| don't know how comfortable or feasible walking on it would
| be, but I bet a cat could learn pretty quick to catch on to
| it and then push off along a desired vector, and they're
| already better at gyroscopic pointing than we are.
| robbedpeter wrote:
| Diapers, maybe, or the litter / pan would have to be under a
| constant slight suction? A big enough hamster wheel to give the
| cat gravity?
|
| Someone's gonna have to answer this question in the next decade
| when rich space tourists want to bring their pets.
|
| Heck, a space cat live stream could probably fund a significant
| part of a new station.
| emerged wrote:
| It wouldn't be a super ethical test.. but I wonder if a cat would
| adapt and start doing some really crazy ninja moves all over the
| place, if you left him in zero-g for a few years.
| Epiphany21 wrote:
| Unethical? Have you seen the inside of the ISS? It's cat heaven
| with all the cables and stuff hanging around, and nothing is
| too high to jump on when you're almost weightless :)
| secondaryacct wrote:
| You misunderstand cat adaptation !!! These little bastards
| would learn to swim lazily before spending any effort on ninja
| moves :D Have you seen a well-fed pampered cat, the thing will
| meow for his food before even turning his head towards its
| human slave.
|
| Those auto righting reflexes are just there to ensure their
| eternal survival when presented to (rarer and rarer) danger.
|
| They're Gods making us do their bidding while they pretend
| we're the masters :D
| hjek wrote:
| This is animal abuse!
| madacol wrote:
| http://paulgraham.com/heresy.html
| c22 wrote:
| Do cats in zero-g fall?
| glouwbug wrote:
| Considering cats fall feet first and buttered toast butter side
| down you can power your spaceship by taping buttered toast to
| your cat's back and attaching the cat toast contraption to the
| rotor of a generator
| FabHK wrote:
| That experiment has been performed and indeed produces
| surplus energy, according to reliable sources :-)
|
| https://www.youtube.com/watch?v=Z8yW5cyXXRc
| Rebelgecko wrote:
| I think this post is using a technically-wrong-but-still-more-
| or-less-gets-the-point-across definition of "zero-g"
| yupper32 wrote:
| It's relative.
| ISL wrote:
| To a reasonable approximation, cats only fall in zero-g.
| draw_down wrote:
___________________________________________________________________
(page generated 2022-04-11 23:00 UTC)