the ultimate physicists?

Well, they don't defy physics so much as they teach us about it.

Picture this.

Its the 1960s.

Bell bottoms, peace signs and a nasty cold war between the U.S.

and the Soviet Union.

Suddenly, the president of the United States goes rogue and announces we are going to the moon!

“What the Physics?

The Moon?

!” Says NASA.

“We have some questions about that.” See, NASA had already learned from early space flight that moving around when youre weightless isnt easy.

They wanted to know the best way to get from point A to point B without the help of gravity.

So they did what anyone in their position would do.

They turned to cats.

More precisely, they turned to Stanford University engineer Thomas Kane.

And he turned to cats.

Because as everyone knows cats are special.

They do all kinds of matrix-level stuff like seeming to defy the laws of physics Before I go any further I have to ask that you please dont test any of this out on Mr.

Whiskers.

Okay, the basic idea is that if you drop a cat belly up, it will reorient itself in midair without pushing off anything for leverage and land on its feet.

And according to the laws of motion, it doesnt seem like that should be able to happen.

We even have a name for why.

Its called the law of conservation of angular momentum.

Or as I like to call it: spinniness.

It just means that something thats spinning will keep spinning until its stopped.

It also means and this is the spooky cat part nothing thats not already spinning can just spontaneously start spinning.

Its easy to see that in action with something thats not a cat, like a spinny office chair.

You can sit down on a spinny chair, but it wont start spinning unless someone gives it a push.

Orits haunted.

And once its spinning it will keep spinning unless something interferes with it, like resistance from the air or friction.

So, you need another force to change an objects angular momentum.

Otherwise, it stays the same.

But a falling cat seemingly changes its angular momentum without any outside force.

And its taken a bunch of different scientists a lot of time and research to figure out how they do it.

For a while, the theory was that our feline friends must be doing some work.

Like maybe they push off from a surface at the last second, to give themselves initial rotation as they begin to fall.

But in 1894, a physiologist named Marey took a series of high-resolution photographs of a cat falling.

Actually, that poor cat got dropped.

Again, please dont try this.

Heres what the photos show: First: The cat started out fully upside down.

Second: It didnt push off from anything.

And finally: The cat still turned in mid air and landed on its feet!

Like I said matrix-level!

What scientists at the time werent thinking about is that cats are a lot more flexible than, say, a spinny chair.

And they have better instincts well, usually.

So when scientists finally considered that cats can move all on their own, they came up with all kinds of ideas about how cats twist and contort their bodies to turn in midair.

Marey concluded that the cat in the photos used a “tuck and turn” method.

First, it tucked in its front legs and stretched out its back legs while turning the front of its body.

Then it tucked its back legs and stretched out its front legs to turn the back.

This method would be kind of like moving your arms while spinning on that office chair.

Pull your arms in, and youll spin faster.

Stretch them out, and youll slow back down.

That works because when you move your arms, youre changing your moment of inertia, so your velocity changes to maintain angular momentum.

In cat terms, the idea was that a cat tucked its front legs, making the front half of its body spin faster than the back.

Then it tucked its back legs to allow the rest of its body to catch up.

But a few decades later, two Dutch physiologists studied the problem again.

And they argued for a different method, which is now known as the “bend and twist” model.

Not to be confused with the bend and snap...very different outcome.

[Elle Woods] So you bend and snap.

[Athena Brensberger] They suggested that the halves of a cats body are like two cylinders that can twist in opposite directions.

Each half puts an equal and opposite force on the other.

That allows them to rotate and cancels out their angular momenta.

Then, when the cat straightens out, its flipped over.

In the 1960s, Kane, the Stanford engineer who attracted NASAs attention, built on both of those models.

He also came up with equations and computer models to simulate a cats movement in the air.

And Kane determined that cats super flexible spines are moving around a lot when they fall.

But theyre mostly bending, not twisting.

Or snapping.

As it falls, the cat bends forward, to the side, back, to the other side, and forward again.

And when the front part of the cat moves around, the rest of its body rotates in the opposite direction.

That allows the cat to flip and land on its feet.

In reality, cats are probably using a combination of movements to eventually land upright.

But what theyre not doing is defying the laws of physics.

And weve been able to take that information and apply it to all sorts of things.

Like Kanes research did help NASA.

He determined that any object could rotate without an outside force.

To demonstrate the method to astronauts, he took pictures of a trampoline athlete who wore a spacesuit while performing cat-like twists.

To this day, astronauts are trained to mimic cats when they turn around in space.

Similar ideas informed the Hubble Space telescope, which relies on spinning wheels called gyroscopes to generate angular momentum.

And in robotics, cats are inspiring new designs to help robots fall and land without breaking.

So cats are the ultimate physicists.

They dont defy physics so much as they teach us about it.

And the more we learn from cats, preferably without dropping any more of them, the more mind- (and body-) bending stuff we can do, both here on Earth and way out in space.