http://m.youtube.com/#/watch?v=O9XtK6R1QAk&desktop_uri=%2Fwatch%3Fv%3DO9XtK6R1QAk

The cruelty of kicking a cat aside, why don’t the cats in the video quickly orientate their bodies to the surface they are approaching as rapidly in zero g as they do in one g?

Isn’t a falling cat in one g experiencing the same things as it does in zero g?

It’s more apparent in the video with the white cat than the ginger one.

The cruelty of kicking a cat aside

rtsp://v3.cache5.c.youtube.com/CjYLENy73wIaLQkJQHWkK-3VOxMYDSANFEIJbXYtZ29vZ2xlSARSBXdhdGNoYInf6uaB6e6FUAw=/0/0/0/video.3gp,

my browser doesn’t recognise this url.

Boris said:

rtsp://v3.cache5.c.youtube.com/CjYLENy73wIaLQkJQHWkK-3VOxMYDSANFEIJbXYtZ29vZ2xlSARSBXdhdGNoYInf6uaB6e6FUAw=/0/0/0/video.3gp,

my browser doesn’t recognise this url.

Try

http://www.youtube.com/watch?v=O9XtK6R1QAk

Spiny Norman said:

http://www.youtube.com/watch?v=O9XtK6R1QAk

That’s hilarious.

guessing here. the cat in freefall doesn’t experience the initial acceleration and so can’t work out which way is “down”. also looking at the vid the cats are trying to orientate themselves to the “ground” but the lack of gravity makes this hard as i’m sure you would notice if you dropped a cat from a great height. and didn’t have to contend with wind resistance etc.

> why don’t the cats in the video quickly orientate their bodies to the surface they are approaching as rapidly in zero g as they do in one g?

Perhaps it has something to do with cats disliking car travel. Car travel puts cuts under local accelerations other than one g. Perhaps they’re space sick, it doesn’t look like it but their semicircular canals wouldn’t be feeding them useful balance information.

If I was dropped in one g with enough space, I would use air resistance to help me orientate. In zero g, the air is going in all directions.

It’d be very interesting to try out intermediate g forces, 1/2 g, 1/4 g etc.

This cat in zero gravity has a lot of trouble but eventually does land on its (front) feet.

http://www.youtube.com/watch?v=JAWuMd6GOfs

The cat seems to have the right reflexes but has as much difficulty judging angular momentum as a person canoeing for the first time. You know what I mean? “If the canoe is going to the right of where you want to go then push on the right paddle” is a recipe for disaster. You need “if the canoe is swinging clockwise then push on the right paddle”. I figure that given enough practice a cat would get it right in zero g, just as a person in a canoe will sooner or later get it right.

Boris said:

rtsp://v3.cache5.c.youtube.com/CjYLENy73wIaLQkJQHWkK-3VOxMYDSANFEIJbXYtZ29vZ2xlSARSBXdhdGNoYInf6uaB6e6FUAw=/0/0/0/video.3gp,

my browser doesn’t recognise this url.

No idea where that URL came from, Boris. rtsp://… Is that even a thing?

Anyway, I assume its just another aspect of my iPad’s inability to copy and paste stuff in any useful or practical way.

AFAICT, the address Spiny Norman posted links to the video I was intending to share.

mollwollfumble said:

This cat in zero gravity has a lot of trouble but eventually does land on its (front) feet.

http://www.youtube.com/watch?v=JAWuMd6GOfs

The cat seems to have the right reflexes but has as much difficulty judging angular momentum as a person canoeing for the first time. You know what I mean? “If the canoe is going to the right of where you want to go then push on the right paddle” is a recipe for disaster. You need “if the canoe is swinging clockwise then push on the right paddle”. I figure that given enough practice a cat would get it right in zero g, just as a person in a canoe will sooner or later get it right.

cats don’t always get it right.
Wish it would happen more often.

esselte said:

Isn’t a falling cat in one g experiencing the same things as it does in zero g?

Air resistance is the only thing that distinguishes free-fall from zero-g. Strictly speaking, once an object reaches terminal velocity, it is no longer in free-fall as the upward force from the air is the same as the upward force the ground supplies when resting on the ground.

KJW said:

esselte said:

Isn’t a falling cat in one g experiencing the same things as it does in zero g?

Air resistance is the only thing that distinguishes free-fall from zero-g. Strictly speaking, once an object reaches terminal velocity, it is no longer in free-fall as the upward force from the air is the same as the upward force the ground supplies when resting on the ground.

That’s what I meant, so given the video it seems obvious that the instinctive ‘calculations’ a cat makes to land on its feet happens before it finds itself in free fall, whilst its still experiencing positive g. Once it’s in zero g, the cat doesn’t have a clue where is up and where is down, and can’t orientate its body based on the visual cues of a rapidly approaching surface with anything like the efficiency it can orientate based on a previous knowledge of which direction is down.

So, why are cats not able to orientate their bodies to an approaching surface efficiently?

esselte said:

That’s what I meant, so given the video it seems obvious that the instinctive ‘calculations’ a cat makes to land on its feet happens before it finds itself in free fall, whilst its still experiencing positive g. Once it’s in zero g, the cat doesn’t have a clue where is up and where is down, and can’t orientate its body based on the visual cues of a rapidly approaching surface with anything like the efficiency it can orientate based on a previous knowledge of which direction is down.

Immediately the cat starts to fall, it experiences an abrupt change in the acceleration it senses (from 9.8ms^–2 to zero), and it most likely uses the direction of this change to orient itself. When in zero-g itself, there is no abrupt change and there is no other sense of the vertical direction, so the cat can’t orient itself. It is unlikely to be the wind the cat senses, as the cat seems to orient itself before it even starts to move.

KJW said:

It is unlikely to be the wind the cat senses, as the cat seems to orient itself before it even starts to move.

I disagree. Cats continue to re-orientate themselves as they fall. It seems likely to me that it is a combination of the initial change of acceleration, removal of the force applied to their feet, and the wind as they fall.

The Rev Dodgson said:

KJW said:

It is unlikely to be the wind the cat senses, as the cat seems to orient itself before it even starts to move.

I disagree. Cats continue to re-orientate themselves as they fall. It seems likely to me that it is a combination of the initial change of acceleration, removal of the force applied to their feet, and the wind as they fall.

I would say that the sense of the wind is more about the cat adjusting its aerodynamic properties and making corrections to any aerodynamic alterations to its orientation as it falls, rather than being used to orient itself in the first place. By the time the cat is falling fast enough for the wind to be of any significance, the cat has already oriented itself correctly, and any adjustments the cat needs to make has been caused by the wind itself and the cat will correct itself on this basis. So, while I don’t deny that the cat senses the wind as it falls, the wind isn’t what the cat uses to orient itself as far as the conundrum put forward in the opening post is concerned.

The other conundrum concerning the cat righting reflex is with regards to the conservation of angular momentum. Wikipedia has an article that explains the cat righting reflex and includes the following animation which shows how the cat orients itself while maintaining zero angular momentum:

KJW said:

The Rev Dodgson said:

KJW said:

It is unlikely to be the wind the cat senses, as the cat seems to orient itself before it even starts to move.

I disagree. Cats continue to re-orientate themselves as they fall. It seems likely to me that it is a combination of the initial change of acceleration, removal of the force applied to their feet, and the wind as they fall.

I would say that the sense of the wind is more about the cat adjusting its aerodynamic properties and making corrections to any aerodynamic alterations to its orientation as it falls, rather than being used to orient itself in the first place. By the time the cat is falling fast enough for the wind to be of any significance, the cat has already oriented itself correctly, and any adjustments the cat needs to make has been caused by the wind itself and the cat will correct itself on this basis. So, while I don’t deny that the cat senses the wind as it falls, the wind isn’t what the cat uses to orient itself as far as the conundrum put forward in the opening post is concerned.

I’m no expert on this, but if I recall correctly, on a long fall cats do no just get themselves right way up near the top and fall feet down the rest of the way. They continue to “revolve” all the way down.

The Rev Dodgson said:

but if I recall correctly,

A quick search suggests that it is possible that I do not.

The Rev Dodgson said:

I’m no expert on this, but if I recall correctly, on a long fall cats do no just get themselves right way up near the top and fall feet down the rest of the way. They continue to “revolve” all the way down.

Hmmm. I don’t think any ethics committee would pass any experiments to test this. The “Vomit Comet” experiments would be closest one could come to test this, but the crucial wind component would be absent.

KJW said:

The Rev Dodgson said:

I’m no expert on this, but if I recall correctly, on a long fall cats do no just get themselves right way up near the top and fall feet down the rest of the way. They continue to “revolve” all the way down.

Hmmm. I don’t think any ethics committee would pass any experiments to test this. The “Vomit Comet” experiments would be closest one could come to test this, but the crucial wind component would be absent.

Case studies such as:

http://sciencebasedlife.wordpress.com/2012/04/13/how-do-cats-survive-falls-from-great-heights/

Not the best evidence, but evidence nonetheless (if was revolving all the way down, surely mortality would be the same from greater heights?)

poikilotherm said:

Case studies such as:

http://sciencebasedlife.wordpress.com/2012/04/13/how-do-cats-survive-falls-from-great-heights/

Not the best evidence, but evidence nonetheless (if was revolving all the way down, surely mortality would be the same from greater heights?)

ThIs Wikipedia article suggests that studies such as the one above probably suffers from selection bias.

poikilotherm said:

KJW said:

The Rev Dodgson said:

I’m no expert on this, but if I recall correctly, on a long fall cats do no just get themselves right way up near the top and fall feet down the rest of the way. They continue to “revolve” all the way down.

Hmmm. I don’t think any ethics committee would pass any experiments to test this. The “Vomit Comet” experiments would be closest one could come to test this, but the crucial wind component would be absent.

Case studies such as:

http://sciencebasedlife.wordpress.com/2012/04/13/how-do-cats-survive-falls-from-great-heights/

Not the best evidence, but evidence nonetheless (if was revolving all the way down, surely mortality would be the same from greater heights?)

After some more thought:

If a cat is dropped with little or no angular momentum then it can right itself and then stay in that position.

On the other hand if it falls with a significant angular momentum (as, I guess, would normally be the case) then it will continue to rotate after reaching feet downwards position, so the best it can do is to maximise feet down time, and minimise feet up time.

On a long fall on the other hand it is possible that it can use air resistance to lose angular momentum, so may be able to get into a feet down position without rotation before it hits the ground.

Just my guesswork.

There is also the buttered cat paradox :-)

KJW said:

poikilotherm said:

Case studies such as:

http://sciencebasedlife.wordpress.com/2012/04/13/how-do-cats-survive-falls-from-great-heights/

Not the best evidence, but evidence nonetheless (if was revolving all the way down, surely mortality would be the same from greater heights?)

ThIs Wikipedia article suggests that studies such as the one above probably suffers from selection bias.

Of course, it’s a case study!

poikilotherm said:

KJW said:

poikilotherm said:

Case studies such as:

http://sciencebasedlife.wordpress.com/2012/04/13/how-do-cats-survive-falls-from-great-heights/

Not the best evidence, but evidence nonetheless (if was revolving all the way down, surely mortality would be the same from greater heights?)

ThIs Wikipedia article suggests that studies such as the one above probably suffers from selection bias.

Of course, it’s a case study!

series…

The Rev Dodgson said:

On the other hand if it falls with a significant angular momentum (as, I guess, would normally be the case) then it will continue to rotate after reaching feet downwards position, so the best it can do is to maximise feet down time, and minimise feet up time.

The ability to rotate with zero angular momentum implies the ability to maintain orientation with non-zero angular momentum. I guess the only requirement would be for the cat to correctly determine the initial conditions.

A long time ago, there was a discussion about how one could get from one topic to a totally different topic by following the links of Wikipedia articles. With this in mind, it is interesting to note that the last two paragraphs of the falling cat problem has language that is usually associated with the gauge theory of general relativity and particle physics, including the mention of Wilczek (Frank Anthony Wilczek), who (along with Professor David Gross and H. David Politzer) was awarded the Nobel Prize in Physics in 2004 for his role in the discovery of asymptotic freedom in the theory of the strong interaction. Who would thought that one could get from cats to quarks so quickly?!

KJW said:

A long time ago, there was a discussion about how one could get from one topic to a totally different topic by following the links of Wikipedia articles. With this in mind, it is interesting to note that the last two paragraphs of the falling cat problem has language that is usually associated with the gauge theory of general relativity and particle physics, including the mention of Wilczek (Frank Anthony Wilczek), who (along with Professor David Gross and H. David Politzer) was awarded the Nobel Prize in Physics in 2004 for his role in the discovery of asymptotic freedom in the theory of the strong interaction. Who would thought that one could get from cats to quarks so quickly?!

Well cats fit better than dogs:

“ Three quarks for Muster Mark! Sure he hasn’t got much of a bark “

KJW said:

A long time ago, there was a discussion about how one could get from one topic to a totally different topic by following the links of Wikipedia articles. With this in mind, it is interesting to note that the last two paragraphs of the falling cat problem has language that is usually associated with the gauge theory of general relativity and particle physics, including the mention of Wilczek (Frank Anthony Wilczek), who (along with Professor David Gross and H. David Politzer) was awarded the Nobel Prize in Physics in 2004 for his role in the discovery of asymptotic freedom in the theory of the strong interaction. Who would thought that one could get from cats to quarks so quickly?!

Schrodinger?

esselte said:

Schrodinger?

Good one! :-)